BPAP

(R)-(-)-1-(benzofuran-2-yl)-2-propylaminopentane; (-)-BPAP; benzofuranylpropylaminopentane; Knoll's catecholaminergic/serotonergic activity enhancer (CAE/SAE); probably the compound coded FPFS-1169 by Fujimoto. The successor to selegiline and (-)-PPAP in the enhancer series — NOT an MAO inhibitor

BPAP ((R)-(-)-1-(benzofuran-2-yl)-2-propylaminopentane; (-)-BPAP; benzofuranylpropylaminopentane; Knoll's catecholaminergic/serotonergic activity enhancer (CAE/SAE); probably the compound coded FPFS-1169 by Fujimoto. The successor to selegiline and (-)-PPAP in the enhancer series — NOT an MAO inhibitor) is a cognitive & mood research compound. A catecholaminergic/serotonergic activity enhancer (CAE/SAE): it increases the amount of transmitter released per nerve impulse rather than causing release itself. That distinction is the whole class. Amphetamine reverses the transporter and dumps non-vesicular transmitter; BPAP amplifies the vesicular, action-potential-coupled release that is already happening, and does not trigger release on its own. In rat striatal slices the enhancement is mediated by trace amine-associated receptor 1 (TAAR1) — a Gs-coupled, intracellularly located receptor — via increased PKC-mediated phosphorylation, alongside increased VMAT2 loading of vesicles; the effect is reversed by the TAAR1 antagonist EPPTB. The enhancer effect is NOT MAO inhibition and not uptake inhibition: neither clorgyline (MAO-A) nor lazabemide (MAO-B) reproduced it in the same preparation. Separately, and at concentrations six orders of magnitude higher, BPAP is a potent dopamine and norepinephrine reuptake inhibitor (IC50 42 and 52 nM) and a weak serotonin one (640 nM), without amphetamine-like releasing action.

How BPAP works

A catecholaminergic/serotonergic activity enhancer (CAE/SAE): it increases the amount of transmitter released per nerve impulse rather than causing release itself. That distinction is the whole class. Amphetamine reverses the transporter and dumps non-vesicular transmitter; BPAP amplifies the vesicular, action-potential-coupled release that is already happening, and does not trigger release on its own. In rat striatal slices the enhancement is mediated by trace amine-associated receptor 1 (TAAR1) — a Gs-coupled, intracellularly located receptor — via increased PKC-mediated phosphorylation, alongside increased VMAT2 loading of vesicles; the effect is reversed by the TAAR1 antagonist EPPTB. The enhancer effect is NOT MAO inhibition and not uptake inhibition: neither clorgyline (MAO-A) nor lazabemide (MAO-B) reproduced it in the same preparation. Separately, and at concentrations six orders of magnitude higher, BPAP is a potent dopamine and norepinephrine reuptake inhibitor (IC50 42 and 52 nM) and a weak serotonin one (640 nM), without amphetamine-like releasing action.

Proposed benefits

Researched as a catecholaminergic and serotonergic activity enhancer for age-related cognitive decline, learning, dopaminergic function and rodent lifespan.

Where to get BPAP

The evidence for BPAP

Graded by what exists behind each claim.

✅ Clinically validated

• No human being has been given BPAP in any published study. There is no clinical trial, no human pharmacokinetic study, no human safety report and no case series. This is not a compound whose trials failed or whose development stalled after human testing — human testing has not been published at all.
• There is a database trace of a clinical program that never produced a publication. AdisInsight carries a drug profile for FPFS 1169, originator Fujimoto Pharmaceutical, recording a highest development status of phase II for Parkinson's disease with the status line 'no development reported', last updated 23 July 2014. FPFS-1169 appears in the peer-reviewed literature as one of the R-enantiomer compounds in this exact benzofuranylpropylamine series (Maruyama 2004), which is why the identification is probable rather than certain. A registry entry is not a result: no trial, dose, outcome or safety data from that program has been published, and the AdisInsight record itself sits behind a subscription so only the summary lines could be read.
• The parent compound's human record does not transfer. Selegiline is a licensed drug with decades of human data, and BPAP is separated from it by design rather than by accident: the whole point of the series was to keep the enhancer effect and discard the MAO-B inhibition (Knoll 1992; Knoll 1999). Whatever is known about selegiline in people is known about a drug whose primary mechanism this one deliberately lacks.

📊 Correlative data

• There is no human association data either, and that is worth saying plainly rather than padding this section. No cohort, no observational series, no biomarker correlation in humans exists for this molecule, because it has no documented human exposure to correlate with anything.
• The nearest human-adjacent evidence belongs to the enhancer CONCEPT, not to this compound. The concept's human anchor is selegiline, where a dopaminergic enhancer effect has been demonstrated in rat tissue and attributed to TAAR1 agonism, and distinguished from rasagiline — an equally selective MAO-B inhibitor which did not show the enhancer effect and may act as a TAAR1 antagonist (Harsing 2023). That is a genuinely interesting dissociation, and it is a rat-slice result about a human drug, not human data about BPAP.
• One correlative observation about the literature itself, which a reader deserves. The enhancer concept, the shuttle-box learning results, the lifespan results, the tumor result and the TAAR1 mechanism come substantially from one research school — Knoll, Miklya, Harsing and colleagues in Budapest, with the Japanese chemistry group around Yoneda and Shimazu. Independent work exists and is mostly the transporter and neuroprotection pharmacology (Shimazu 2003; Maruyama 2004; Hamabe 2000). The one fully independent attempt at the aging claim found the opposite (Ernyey 2023). This is the same structural caution the Vault applies to the Khavinson bioregulators: a real, testable hypothesis, largely unreplicated outside the group that proposed it.

🧪 Theoretical / extrapolated

• The enhancer mechanism, stated as what it actually claims. BPAP increases the transmitter released per nerve impulse — impulse-propagation-mediated, exocytotic release — without causing release itself. In the isolated rat brainstem it enhanced [3H]-noradrenaline and [3H]-dopamine release at 0.18 micromol/L and [3H]-serotonin at 36 nmol/L, and in discrete brain regions at 10^-12 to 10^-14 M; in vivo it enhanced catecholaminergic and serotonergic activity 30 min after 0.1 microgram/kg subcutaneously, and in the shuttle box it was about 130 times more potent than selegiline at antagonizing tetrabenazine-induced inhibition of performance (Knoll 1999).
• The cleanest experiment in the file proves the mechanism is not MAO inhibition and not reuptake inhibition. In the same preparation, 50 ng/mL was the most effective concentration for enhancing stimulation-induced noradrenaline and dopamine release and 10 ng/mL for serotonin, while neither clorgyline (MAO-A) nor lazabemide (MAO-B) at 250 ng/mL could significantly increase stimulation-induced release. The authors' conclusion is that enhancement is *'clearly different from influencing uptake or MAO'* (Miklya 2003). That is a control experiment doing real work, and it is the reason this compound is not just another MAO-B inhibitor.
• TAAR1: what is shown versus what is proposed. Shown, in rat striatal slices: BPAP potentiated vesicular [3H]dopamine release via TAAR1 mediation, did not induce non-vesicular release (which is what methamphetamine did in the same experiment), had its effect potentiated by N-ethylmaleimide, acted through increased PKC-mediated phosphorylation, and increased VMAT2 operation so that vesicles loaded and released more (Harsing 2022). Also shown: the effect is reversed by the TAAR1 antagonist EPPTB, and it is concentration-limited — across 10^-13 to 10^-11 mol/L the curves for both dopamine and GABA release were bell-shaped (Harsing 2025). Proposed, and labeled as such by the authors themselves: that TAAR1 carries two distinct binding sites, one for releasers and one for enhancers, driving different PKC phosphorylation (Harsing 2022); and that the descending limb of the bell curve reflects TAAR1-D2 heterodimerization switching TAAR1 signaling off and D2 signaling on (Harsing 2025). The word the papers use is 'hypothesized' and 'speculated', and this page uses it too.
• The evidence that 'enhancer' is not one mechanism. 3-F-BPAP, a trifluoropropyl analog, antagonized the enhancer effect of BPAP in the shuttle box while leaving the effects of selegiline and (-)-PPAP unchanged (Knoll 2002). Two enhancer effects that can be pharmacologically separated — a tryptamine-derived one and a phenylethylamine-derived one — which is a much stronger claim than 'these drugs are all enhancers' and is the kind of result that makes a hypothesis testable.
• THE FACT THAT REFRAMES THE WHOLE PRODUCT: at attainable concentrations this is a reuptake inhibitor, not an enhancer. In HEK-293 cells expressing the human transporters, BPAP inhibited uptake with IC50 values of 42 +/- 9 nM (dopamine), 52 +/- 19 nM (norepinephrine) and 640 +/- 120 nM (serotonin), and displaced [125I]RTI-55 binding at 16 +/- 2, 211 +/- 61 and 638 +/- 63 nM. Tyramine, but not BPAP, potentiated norepinephrine release — and BPAP inhibited tyramine-induced release, which the authors note *'may block tyramine-induced adverse effects such as hypertensive crisis'* (Shimazu 2003). Set that against the enhancer concentrations above: 10^-8 M versus 10^-14 M is six orders of magnitude. Whatever a person swallowing a measured volume of a 100mcg/mL solution is doing, the concentrations are far closer to the reuptake-inhibition range than to the range where the enhancer effect was described.
• The rodent lifespan and learning result, with its numbers and its limits. Male Wistar rats, N = 40 per group, treated subcutaneously three times weekly from their 10th week until death with saline, selegiline (0.001 or 0.1 mg/kg) or BPAP (0.0001 or 0.05 mg/kg): rats on either BPAP dose lived significantly longer than saline controls (P < 0.02), BPAP was more potent than selegiline, and 18-month-old rats on 0.0001 mg/kg BPAP learned as well as 3-month-old saline controls in the shuttle box. The authors' conclusion is that the enhancer effect is what extends life (Knoll 2016). In the same cohort, fibromyxosarcoma appeared in 20/40 saline rats versus 8/40 on 0.0001 mg/kg BPAP (P < 0.001) and 7/40 on 0.05 mg/kg (P < 0.01) — and BPAP had no direct cytotoxic effect on medulloblastoma cells and did not alter the cytotoxicity of temozolomide, cisplatin, etoposide or vincristine, so the proposed route is a brain regulation rather than an anti-tumor action (Knoll 2017).
• THE RESULT THAT CUTS AGAINST THE PRODUCT, and it is the only independent test of the aging claim. A separate group ran aged Long-Evans male rats, starting at 27 months, through pot-jumping (motor skill learning), the five-choice serial reaction time task (attention), the Morris water maze (spatial learning) and a cooperation task (social cognition). Average lifespan of the population was 36 months. BPAP could not improve cognitive performance; neither could it prolong lifespan. The authors' own candidate explanation is a ceiling effect — dietary restriction and lifelong cognitive engagement had already benefited these animals (Ernyey 2023). It is one study, in a different strain, starting in old age rather than young adulthood, so it is not a clean refutation of (Knoll 2016) — but it is the only attempt from outside the originating school, and it came back negative.
• Neuroprotection, in cells, by two different proposed routes. BPAP protected cultured cortical neurons under serum-free conditions, an effect blocked by the sigma receptor antagonist BD1063, implicating sigma receptors (Hamabe 2000); and it protected human dopaminergic SH-SY5Y cells from apoptosis induced by the endogenous neurotoxin N-methyl(R)salsolinol through stabilization of mitochondrial membrane potential and induction of anti-apoptotic Bcl-2, with potency depending on absolute stereochemistry (Maruyama 2004). BPAP also protected hippocampal neurons from beta-amyloid at 10^-14 M (Knoll 1999). All cell culture, and three different proposed mechanisms of protection, which is a reason to hold each of them loosely.
• Behavioral pharmacology in rodent mood models, with a dissociation worth noting. Acute but not chronic administration reduced immobility in the forced swimming test, while chronic but not acute administration improved impaired social interaction after stress, with the effect attributed to dopaminergic activation; the olfactory-bulbectomized rat model was also used (Tsunekawa 2008). Acute and chronic dosing producing effects in different tests is exactly what the bell-shaped, adaptive picture would predict, and exactly what makes a human dose hard to guess.
• Higher doses do something different and it is visible behaviorally. BPAP potentiated locomotor activity dose-dependently at 0.3-10 mg/kg in rats, with dopamine release implicated and a D1 antagonist (SCH 23390) used to probe it (Shimazu 2001). Those doses are 3,000 to 100,000 times the enhancer dose used in the lifespan study. Two dose ranges, two pharmacologies, one molecule — and the product on sale gives no guidance about which one a measured volume lands in.

How to read these tiers: they say how much human evidence exists, not how well something works — and ✗ flags harm, never a disappointing trial. How the evidence tiers work →

What BPAP actually does

The claim that makes this molecule interesting is not that it releases transmitter — it is that it does not. Amphetamine and its relatives reverse the monoamine transporter and push transmitter out of the terminal whether or not a nerve impulse arrived. Knoll's “enhancer” class does something else: it increases the amount of transmitter released per impulse — impulse-propagation-mediated, vesicular, exocytotic release — and produces nothing on its own when the neuron is silent. Knoll 1992 established the template with (−)-PPAP, a deprenyl-derived compound reported as “devoid of MAO inhibitory potency” and “devoid of catecholamine-releasing property”. That is two things subtracted at once, and what is left is the enhancer effect in isolation.

BPAP is what you get when you change the ring and keep the effect. Knoll 1999 reports the lineage explicitly: by changing the aromatic ring in PPAP they built compounds “structurally unrelated to the amphetamines”, and out of 65 newly synthesized compounds a tryptamine-derived structure was selected as the potential successor to selegiline. Its numbers: enhanced [³H]-noradrenaline and [³H]-dopamine release from isolated rat brainstem at 0.18 µmol/L and [³H]-serotonin at 36 nmol/L; enhancement in discrete regions at 10⁻¹²–10⁻¹⁴ M; protection of hippocampal neurons from beta-amyloid at 10⁻¹⁴ M; and roughly 130 times the potency of selegiline in the shuttle box against tetrabenazine. Shimazu 2004 calls it “the best experimental tool to study the enhancer regulation” — a tool, which is the honest description of what it has been for 25 years.

The MAO question, answered by a control experiment rather than by assertion. Selegiline's famous property is irreversible MAO-B inhibition, so the obvious suspicion about any descendant is that the “enhancer effect” is just monoamine oxidase inhibition under a new name. Miklya 2003 tested exactly that: in the same preparation, 50 ng/mL BPAP was the most effective concentration for noradrenaline and dopamine and 10 ng/mL for serotonin, while clorgyline (selective MAO-A) and lazabemide (selective MAO-B) at 250 ng/mL could not significantly increase stimulation-induced release. The authors' conclusion is that enhancement is “clearly different from influencing uptake or MAO”. That is the single most load-bearing experiment on this page, and it is the reason the compound is not simply a selegiline analog.

And the dissociation runs both ways, which is what makes the concept testable. Harsing 2023 compared selegiline and rasagiline, two selective MAO-B inhibitors used for the same disease: selegiline stimulated electrically induced [³H]dopamine release without affecting resting release, an enhancer effect related to TAAR1 agonism, while rasagiline showed none and may act as a TAAR1 antagonist. MAO-B inhibition and the enhancer effect are separable in either direction.

TAAR1: what has been shown, and what its own authors call a hypothesis. Shown Harsing 2022: in rat striatal slices BPAP potentiated vesicular [³H]dopamine release with TAAR1 mediation, did not induce non-vesicular release (methamphetamine, run alongside, did), was potentiated by N-ethylmaleimide, acted via increased PKC-mediated phosphorylation, and increased VMAT2 operation so vesicles loaded and released more. Also shown Harsing 2025: the effect is reversed by the TAAR1 antagonist EPPTB, and across 10⁻¹³–10⁻¹¹ mol/L the curves for both dopamine and GABA release are bell-shaped. Proposed, in the authors' own words: that TAAR1 carries two binding sites, one for releasers and one for enhancers — “we have hypothesized”; and that the falling limb of the bell curve is TAAR1–D₂ heterodimerization switching TAAR1 signaling off — “we speculated”. Both are good hypotheses. Neither is a result.

The other proof that “enhancer” is not one thing. Knoll 2002 built 3-F-BPAP, a trifluoropropyl analog, and found it antagonized BPAP's enhancer effect in the shuttle box while leaving selegiline's and PPAP's unchanged. A tryptamine-derived enhancer mechanism and a phenylethylamine-derived one, pharmacologically separable with a tool compound. That is a real, falsifiable structure for a concept that is often described far more loosely than its own literature describes it.

Finally, the fact that reframes the product: at any concentration you could measure out of a dropper, this is a reuptake inhibitor. Shimazu 2003 put BPAP through HEK-293 cells expressing the human transporters and got IC₅₀ values for uptake inhibition of 42 ± 9 nM (dopamine), 52 ± 19 nM (norepinephrine), 640 ± 120 nM (serotonin), with [¹²⁵I]RTI-55 binding displaced at 16 ± 2, 211 ± 61 and 638 ± 63 nM. It confirmed the non-releaser claim in the same paper — tyramine potentiated norepinephrine release and BPAP did not, and BPAP inhibited tyramine-induced release. Compare the two ranges: the enhancer effect is described at 10⁻¹⁴ M and the transporter block sits at 10⁻⁸ M. Six orders of magnitude. Two pharmacologies, one molecule, and nothing on the label to say which one a given volume produces.

Cell, rodent, human — and where it stops

The chain here is cell → rodent → stop, and the interesting part is that the rodent end is unusually rich while the human end is completely empty.

Cells, three times, with three different proposed mechanisms of protection. Hamabe 2000 found BPAP kept cultured cortical neurons alive under serum-free conditions, and the rescue was blocked by the sigma receptor antagonist BD1063 — implicating sigma receptors, with (+)-pentazocine behaving similarly. Maruyama 2004 protected human dopaminergic SH-SY5Y cells from apoptosis induced by the endogenous neurotoxin N-methyl(R)salsolinol, attributing it to “direct stabilization of mitochondrial membrane potential and the induction of anti-apoptotic Bcl-2”, and found potency depended on absolute stereochemistry. Knoll 1999 protected hippocampal neurons from beta-amyloid at 10⁻¹⁴ M. Three papers, three routes — sigma receptors, mitochondrial/Bcl-2, and whatever mediates a femtomolar effect. When one compound is credited with three unrelated protective mechanisms in three preparations, each of them should be held loosely.

Rodent, the headline result, with its actual design. Knoll 2016: male Wistar rats, N = 40 per group, dosed subcutaneously three times weekly from their 10th week of life until death with saline (0.5 mL/kg), selegiline (0.001 or 0.1 mg/kg) or BPAP (0.0001 or 0.05 mg/kg). Rats on either BPAP dose lived significantly longer than saline controls (P < 0.02); BPAP was more potent than selegiline at extending life; and in the shuttle box 18-month-old rats on 0.0001 mg/kg learned as well as 3-month-old saline controls. The stated conclusion is that “the enhancer effect is responsible for life extension”. Knoll 2017 then reported the tumor data from that cohort: fibromyxosarcoma in 20/40 saline rats, 8/40 on 0.0001 mg/kg BPAP (P < 0.001) and 7/40 on 0.05 mg/kg (P < 0.01), with selegiline intermediate. Importantly, they showed BPAP was devoid of direct cytotoxic effect on medulloblastoma cells and did not change the cytotoxicity of temozolomide, cisplatin, etoposide or vincristine — so the proposed mechanism is a brain regulation, not an anti-tumor drug action, and they name interaction with distinct sites on VMAT2 as the main mechanism of the enhancer substances.

Rodent, the behavioral pharmacology, and a dissociation that complicates any dose. Tsunekawa 2008 ran mice and rats through the forced swimming test, social interaction after stress, and the olfactory-bulbectomized model: acute but not chronic administration reduced immobility, while chronic but not acute administration improved impaired social interaction, with the effect attributed to dopaminergic activation. Shimazu 2001 showed the high-dose personality: locomotor potentiation dose-dependently at 0.3–10 mg/kg, in normal, reserpine-treated and 6-hydroxydopamine-lesioned rats, with dopamine release implicated and the D₁ antagonist SCH 23390 used to probe it. Those doses are 3,000 to 100,000 times the lifespan dose.

THE SPECIFIC OBSTACLE TO TRANSFER, and it is not the usual one. Normally the obstacle is that nobody ran the human study. Here there is a second, harder problem: the dose cannot be carried across even in principle, because the dose-response is not monotonic. Two rodent doses five hundred-fold apart produced the same lifespan outcome Knoll 2016, and the striatal concentration-effect curves are bell-shaped Harsing 2025. Body-surface-area scaling — the method this Vault uses everywhere else — assumes a single ascending limb. On a bell curve, a scaled number has no defined relationship to the peak, and you cannot tell from the result whether you are below it, on it, or past it. That is why this page carries no extrapolated dose: not squeamishness, but because the arithmetic's own precondition fails.

Human: nothing. No trial, no pharmacokinetics, no case series, no safety report. The only trace of a human program is a database entry — AdisInsight's profile for FPFS 1169, originator Fujimoto Pharmaceutical, highest status phase II for Parkinson's disease and the line 'no development reported', last updated 23 July 2014. FPFS-1169 appears in the peer-reviewed record as one of the R-enantiomer compounds of this series Maruyama 2004, so the identification is probable rather than certain, and no dose, outcome or adverse event from that program has ever been published. An inventor's proposal exists — Knoll 2001 suggested 0.1 mg/day for human study, one-tenth of the 1 mg/day he proposed for selegiline — and a proposal in a review is not a trial.

And the one independent attempt at the central claim came back negative. Ernyey 2023 took aged Long-Evans males from 27 months through pot jumping (motor skill learning), the five-choice serial reaction time task (attention), the Morris water maze (spatial learning) and a cooperation task (social cognition), in a population whose average lifespan was 36 months. BPAP could not improve cognitive performance; neither could it prolong lifespan. The authors offer a ceiling effect as the explanation — these rats already had dietary restriction and lifelong cognitive engagement working in their favor. Different strain, different starting age, different tests, so not a clean refutation of Knoll 2016. But it is the only test of the claim from outside the school that made it, and the result is the opposite one.

BPAP pharmacokinetics — how much of it actually gets in

Unusually for this catalog the half-life is not a blank — it is a rat number, and the rat study is thorough. Magyar 2002 gave rats ¹⁴C-labeled (−)-BPAP and followed the radioactivity. It was well absorbed after intraperitoneal, subcutaneous AND oral administration — oral absorption was measured, not assumed — with C_max at 30–60 minutes, a similar distribution profile in brain regions with a brain peak at 30 minutes, and a second plasma peak at 4 hours indicating enterohepatic circulation. Elimination was preferentially urinary with stool secondary, and more than 90% was recovered in the excreta within 72 hours. The terminal half-life, t_1/2β, was 5.5–5.8 hours.

What that half-life does and does not license, because no human has ever been measured. There is no human pharmacokinetic study of BPAP in any indication. The reasoning that bounds a human estimate, labeled as reasoning: this is a small, lipophilic secondary amine around 245 Da with hepatic metabolism and renal excretion — the physicochemical profile that crosses the gut wall and the blood-brain barrier passively, which the brain peak at 30 minutes in the rat confirms. Clearance normalized to body mass generally falls from rat to human, so the direction of the error is that a human terminal half-life would be the rat's 5.5–5.8 hours or longer, not shorter. That direction is reliable; the magnitude is not, because interspecies half-life scaling fails routinely for individual compounds whenever a specific enzyme dominates clearance, and nobody has published which enzyme clears this one.

The enterohepatic finding is the part that should not be waved past. A second plasma peak at 4 hours means the compound is excreted into bile and reabsorbed from the gut. Practically, that flattens and lengthens the exposure curve beyond what a single terminal half-life suggests, and it makes exposure sensitive to things nobody has studied here — gut transit, bile flow, anything binding in the lumen. For a compound whose active window may be bell-shaped Harsing 2025, a recirculating exposure profile is not a minor detail: it means the concentration wanders across the curve for hours after a dose rather than rising and falling once.

The bioavailability question, stated honestly. Secondary sources describe BPAP as having substantial oral bioavailability, citing Magyar 2002. What that paper's abstract actually supports is that radioactivity was well absorbed by the oral route in rats. Absorbed radiolabel is not the same measurement as an oral bioavailability fraction for intact parent drug, and no F value for BPAP in any species was located. This distinction matters because the vendor sells a liquid, and how much of a swallowed dose arrives intact is exactly the number that would let anyone reason about a volume.

The arithmetic that matters most here is not a half-life, it is the gap between two concentration ranges. The enhancer effects were described at 10⁻¹²–10⁻¹⁴ M in tissue Knoll 1999 and at 10⁻¹³–10⁻¹¹ mol/L in striatal slices Harsing 2025; transporter inhibition begins around 10⁻⁸ M Shimazu 2003. The in vivo rodent doses split the same way — 0.0001–0.05 mg/kg s.c. for the lifespan and learning work Knoll 2016 against 0.3–10 mg/kg for locomotor activation and dopamine release Shimazu 2001. Without a human PK study there is no way to know which of those two worlds a measured volume of a 100 mcg/mL solution lands in, and the two worlds are different drugs. That is the honest substitute for the human number nobody has measured.

What would have to be true, and how you would know it was not

Four predictions. The first two are the ones that decide whether this product is doing anything at all, the third names the lab result most likely to alarm somebody for the wrong reason, and the fourth cuts against the compound.

1. If a measurable volume is doing anything, it is reuptake inhibition — and reuptake inhibition has vital signs. The enhancer effect was described at 10⁻¹⁴ M; transporter block starts around 42–52 nM Shimazu 2003. A norepinephrine reuptake inhibitor at circulating concentrations produces a predictable, measurable signature: resting heart rate up, systolic and diastolic blood pressure up, sleep-onset latency up. The instrument is a blood pressure cuff and a wrist tracker, the direction is up, and the window is days rather than weeks. If a volume that supposedly delivers a femtomolar enhancer effect measurably raises resting heart rate and blood pressure, then the pharmacology in play is the transporter block, not the enhancer effect — and everything on this page about lifespan and learning, which was generated at doses five orders of magnitude lower, stops applying. This is the single cheapest experiment anyone could run on this compound and nobody has published it in any species at human-relevant exposure.

2. The falsification test for a bell-shaped dose-response, which almost nobody runs correctly. If the curve really is bell-shaped Harsing 2025, then the standard approach — take some, take more if nothing happens — is exactly backwards, and it produces a specific, checkable pattern: a smaller dose outperforming a larger one. The measurement has to be a validated instrument rather than a feeling, because the expected effects are subtle: a psychomotor vigilance task (reaction time and lapses) or a digit-span test, done at the same time of day, for a week per dose level, with the order randomized and at least a week between levels given the enterohepatic recirculation Magyar 2002. If bigger is reliably better, the bell-shaped claim is wrong for this compound in humans, which would be an interesting finding in its own right and would make ordinary dose-scaling legitimate again.

3. The lab result that will be misread, with a direction and a reason. Norepinephrine transporter inhibition raises measured catecholamines and metanephrines without any tumor present. So plasma free metanephrines, plasma catecholamines, and 24-hour urinary catecholamines and metanephrines should read HIGH on this compound Shimazu 2003, and anyone who has those drawn during an unrelated workup for palpitations or high blood pressure risks a false positive for pheochromocytoma — which leads to imaging, not reassurance. Retest window: draw them after a washout of at least 5 half-lives, which the rat data puts at roughly 30 hours Magyar 2002 with the honest caveat that human clearance is unmeasured and enterohepatic recirculation argues for longer. A second, quieter prediction from the same mechanism: prolactin down, because raising synaptic dopamine at the pituitary suppresses it.

4. THE PREDICTION THAT CUTS AGAINST THE COMPOUND, and it comes from the aging literature rather than from doubt. Ernyey 2023 found no cognitive benefit and no lifespan extension in aged rats, and proposed a ceiling effect — the animals were already dietarily restricted and cognitively engaged. If that explanation is right, it generates an uncomfortable prediction about people: the benefit should be smallest in exactly the population most likely to buy this, i.e. those already exercising, eating carefully and working cognitively demanding jobs, and largest in the sedentary and unstimulated. That is testable and nobody has stratified anything this way. The falsifiable version for one person: the honest prior for a healthy, active adult on any validated cognitive instrument is no change, and a well-run n-of-1 should expect to measure nothing.

What nobody has tested yet

Five experiments nobody has run. The first is the one that would make everything else on this page relevant or irrelevant, and it costs almost nothing.

1. Give it to a person and measure the blood. There is no human pharmacokinetic study of BPAP, which means nobody knows what plasma concentration a swallowed volume produces — and because this compound's two pharmacologies sit six orders of magnitude apart Knoll 1999 Shimazu 2003, the concentration is the mechanism. One single-dose time course with LC-MS/MS would settle whether a dropper delivers an enhancer dose or a reuptake-inhibitor dose. Every other question here is downstream of that one, and it has been available to answer since 1999.

2. Does the enhancer effect exist outside the school that named it? The founding pharmacology, the shuttle-box results, the lifespan result, the tumor result and the TAAR1 mechanism come substantially from Knoll, Miklya, Harsing and colleagues Knoll 1999 Knoll 2016 Knoll 2017 Harsing 2022 Harsing 2025. Independent groups have replicated the transporter pharmacology Shimazu 2003 and the neuroprotection Maruyama 2004 Hamabe 2000 — the conventional parts. No independent laboratory has published the femtomolar enhancer effect itself. The experiment is a rat brainstem preparation and a scintillation counter, and the reason it matters is that an effect at 10⁻¹⁴ M is a hard measurement, which is precisely the kind that needs outside confirmation.

3. The lifespan study, repeated on the original protocol. Ernyey 2023 is the only independent aging test and it differed from Knoll 2016 in three ways at once: strain (Long-Evans vs Wistar), starting age (27 months vs the 10th week of life), and endpoints (a four-test cognitive battery vs shuttle box). So it is not the same experiment with a different answer — it is a different experiment. Nobody has run the Knoll protocol independently: young-adult start, subcutaneous, three times weekly, 0.0001 mg/kg, to death. Until someone does, the strongest claim attached to this molecule rests on one laboratory's cohort.

4. Whether the bell curve is real in a whole animal. The bell-shaped concentration-effect relationship is the compound's most consequential property and it has been demonstrated in striatal slices Harsing 2025. Nobody has shown a bell-shaped behavioral dose-response in a live animal across the full range — which would mean dosing a single behavioral endpoint at eight or ten levels from 0.00001 to 1 mg/kg and showing performance rise and then fall. It is one experiment, it would establish the shape everyone is already reasoning from, and its absence is why the dose section of this page refuses to extrapolate.

5. The tumor finding, followed up at all. Knoll 2017 reported fibromyxosarcoma in 7–8 of 40 BPAP-treated rats against 20 of 40 controls and concluded “it seems reasonable to test in humans low dose DEP or BPAP treatment against the spreading of a malignant tumor”. That was 2017. No follow-up of any kind has been published — not a replication in another rodent cohort, not a different tumor model, not a human study. A single unreplicated tumor-incidence result from a longevity cohort is a hypothesis, and the striking thing is that a claim this large has sat untouched for nearly a decade. Nothing on this page should be read as a claim that this compound treats, prevents or affects cancer in a person.

BPAP — its own safety story, not its class's

The first safety fact is the plainest one available: nobody knows, because no human has been given this in a published study. There is no adverse-event table, no NOAEL for humans, no interaction list, no contraindication, no overdose description and no report of what happens if you stop. This is a different situation from a compound whose trials found problems, and it is also different from one whose trials found nothing — there are no trials. Every risk below is predicted from the mechanism and labeled as such.

The dominant predicted risk is sympathomimetic, and it comes from the pharmacology that is actually attainable. At 42–52 nM this compound blocks dopamine and norepinephrine reuptake Shimazu 2003. That predicts what every NET inhibitor predicts: raised resting heart rate and blood pressure, delayed sleep onset, reduced appetite, and jitteriness — and it predicts them for anyone whose dose reaches those concentrations, which is the likely case for any measurable volume. The mitigation follows from the same mechanism and is not a supplement: a blood pressure cuff and a resting heart rate from any wrist tracker, at baseline and across the first two weeks. Those two numbers are the on-mechanism readout, they cost nothing, and they are the only early warning available for a compound with no safety literature.

One classic risk that this compound's own data argues AGAINST, which is worth stating because it will otherwise be assumed. BPAP descends from selegiline, and selegiline at MAO-inhibiting doses carries the tyramine interaction — the aged-cheese hypertensive crisis. Two published findings say that concern does not transfer. First, the enhancer effect is not MAO inhibition: clorgyline and lazabemide could not reproduce it Miklya 2003, and the whole design lineage was built to drop MAO inhibition Knoll 1992. Second and more directly, BPAP inhibited tyramine-induced norepinephrine release, and the authors state it “may block tyramine-induced adverse effects such as hypertensive crisis” Shimazu 2003. So the predicted direction here is protective rather than dangerous — from a cell and synaptosome study, in the absence of any human data, which is how firmly it should be held.

The interaction risk that IS mechanistically real, and nobody has studied it. A dopamine and norepinephrine reuptake inhibitor sitting on top of another agent that raises synaptic monoamines — an SSRI or SNRI, bupropion, a stimulant, an MAO inhibitor, or selegiline itself — is additive at the transporter by arithmetic, not by speculation. The most serious specific version is combination with an MAO inhibitor, where blocking reuptake while breakdown is also blocked is the configuration behind the worst monoamine reactions in clinical pharmacology. No interaction study of BPAP with anything has ever been published, in any species. Anyone already on a monoamine-active prescription is combining two drugs where one of them has no human data at all.

The risk that is unique to this compound rather than to its class: you may be aiming at a target you cannot see. If the concentration-effect curve is bell-shaped Harsing 2025, then dose-escalation — the normal response to feeling nothing — can carry someone off the top of the useful range and into the reuptake-inhibitor range, which is where the cardiovascular liability lives. The failure mode is not an overdose in the ordinary sense; it is silently switching drugs while thinking you increased one. The mitigation is the one thing the vendor's format does not support: precise, reproducible, small measurement, from a solution with no published human concentration-response to calibrate against.

What the animal record does and does not reassure about. On the positive side, rats dosed three times weekly from the 10th week of life until death at 0.0001 and 0.05 mg/kg lived longer than controls and had less tumor manifestation, not more Knoll 2016 Knoll 2017 — a chronic-exposure safety signal pointing the right way, which is genuinely uncommon. Against it: those doses are five to six orders of magnitude below the vendor's unit and were given subcutaneously, so they are reassurance about a different exposure than the one being sold. And there is no repeat-dose toxicology, no genotoxicity panel and no reproductive study for this compound in any species that I could locate.

Finally, you cannot verify what is in the bottle. The product page prints a concentration, a volume and a total content, and no CAS number, molecular formula, molecular weight or purity figure. It also prints no route of administration and explicitly disclaims “liquid oral use, injection use, self-administration use”. Stereochemistry is not a detail for this molecule: Maruyama 2004 found protective potency depended on absolute stereochemical structure, with dextrorotatory and levorotatory compounds behaving differently, and all of the enhancer pharmacology is for the (R)-(−) enantiomer. A label reading “BPAP” with no optical rotation, no chiral purity and no certificate distinguishes nothing — and a racemate would be half a different compound.

Sources read for this page

• Knoll J, Yoneda F, Knoll B, Ohde H, Miklya I. (-)1-(Benzofuran-2-yl)-2-propylaminopentane, [(-)BPAP], a selective enhancer of the impulse propagation mediated release of catecholamines and serotonin in the brain. British Journal of Pharmacology 1999;128(8):1723-32 · PMID 10588928
• Yoneda F, Moto T, Sakae M, Ohde H, Knoll B, Miklya I, Knoll J. Structure-activity studies leading to (-)1-(benzofuran-2-yl)-2-propylaminopentane, ((-)BPAP), a highly potent, selective enhancer of the impulse propagation mediated release of catecholamines and serotonin in the brain. Bioorganic & Medicinal Chemistry 2001;9(5):1197-212 · PMID 11377178
• Knoll J, Knoll B, Torok Z, Timar J, Yasar S. The pharmacology of 1-phenyl-2-propylamino-pentane (PPAP), a deprenyl-derived new spectrum psychostimulant. Archives Internationales de Pharmacodynamie et de Therapie 1992;316:5-29 · PMID 1356324
• Knoll J, Miklya I, Knoll B, Yasusa T, Shimazu S, Yoneda F. 1-(Benzofuran-2-yl)-2-(3,3,3-trifluoropropyl)aminopentane HCl, 3-F-BPAP, antagonizes the enhancer effect of (-)-BPAP in the shuttle box and leaves the effect of (-)-deprenyl unchanged. Life Sciences 2002;71(17):1975-84 · PMID 12175892
• Magyar K, Lengyel J, Bolehovszky A, Knoll B, Miklya I, Knoll J. The fate of (-)1-(benzofuran-2-yl)-2-propylaminopentane . HCl, (-)-BPAP, in rats, a potent enhancer of the impulse-evoked release of catecholamines and serotonin in the brain. European Journal of Drug Metabolism and Pharmacokinetics 2002;27(3):157-61 · PMID 12365195
• Miklya I, Knoll J. Analysis of the effect of (-)-BPAP, a selective enhancer of the impulse propagation mediated release of catecholamines and serotonin in the brain. Life Sciences 2003;72(25):2915-21 · PMID 12697274
• Shimazu S, Tsunekawa H, Yoneda F, Katsuki H, Akaike A, Janowsky A. Transporter-mediated actions of R-(-)-1-(benzofuran-2-yl)-2-propylaminopentane. European Journal of Pharmacology 2003;482(1-3):9-16 · PMID 14659999
• Shimazu S, Takahata K, Katsuki H, Tsunekawa H, Tanigawa A, Yoneda F, Knoll J, Akaike A. (-)-1-(Benzofuran-2-yl)-2-propylaminopentane enhances locomotor activity in rats due to its ability to induce dopamine release. European Journal of Pharmacology 2001;421(3):181-9 · PMID 11516435
• Hamabe W, Fujita R, Yasusa T, Yoneda F, Yoshida A, Ueda H. (-)1-(Benzofuran-2-yl)-2-propylaminopentane shows survival effect on cortical neurons under serum-free condition through sigma receptors. Cellular and Molecular Neurobiology 2000;20(6):695-702 · PMID 11100977
• Maruyama W, Yi H, Takahashi T, Shimazu S, Ohde H, Yoneda F, Iwasa K, Naoi M. Neuroprotective function of R-(-)-1-(benzofuran-2-yl)-2-propylaminopentane, [R-(-)-BPAP], against apoptosis induced by N-methyl(R)salsolinol, an endogenous dopaminergic neurotoxin, in human dopaminergic neuroblastoma SH-SY5Y cells. Life Sciences 2004;75(1):107-17 · PMID 15102525
• Tsunekawa H, Noda Y, Miyazaki M, Yoneda F, Nabeshima T, Wang D. Effects of (R)-(-)-1-(benzofuran-2-yl)-2-propylaminopentane hydrochloride [(-)-BPAP] in animal models of mood disorders. Behavioural Brain Research 2008;189(1):107-16 · PMID 18243357
• Knoll J, Miklya I. Longevity study with low doses of selegiline/(-)-deprenyl and (2R)-1-(1-benzofuran-2-yl)-N-propylpentane-2-amine (BPAP). Life Sciences 2016;167:32-38 · PMID 27777099
• Knoll J, Baghy K, Eckhardt S, Ferdinandy P, Garami M, Harsing LG Jr, Hauser P, Mervai Z, Pocza T, Schaff Z, Schuler D, Miklya I. A longevity study with enhancer substances (selegiline, BPAP) detected an unknown tumor-manifestation-suppressing regulation in rat brain. Life Sciences 2017;182:57-64 · PMID 28623006
• Harsing LG, Knoll J, Miklya I. Enhancer Regulation of Dopaminergic Neurochemical Transmission in the Striatum. International Journal of Molecular Sciences 2022;23(15):8543 · PMID 35955676
• Harsing LG, Szenasi G, Feher B, Miklya I. Regulation by Trace Amine-Associated Receptor 1 (TAAR1) of Dopaminergic-GABAergic Interaction in the Striatum: Effects of the Enhancer Drug (-)BPAP. Neurochemical Research 2025;50(2):94 · PMID 39903411
• Harsing LG Jr, Timar J, Miklya I. Striking Neurochemical and Behavioral Differences in the Mode of Action of Selegiline and Rasagiline. International Journal of Molecular Sciences 2023;24(17):13334 · PMID 37686140
• Ernyey AJ, Kassai F, Kozma K, Plangar I, Somfai Z, Miklya I, Gyertyan I. Age-related decline of various cognitive functions in well-experienced male rats treated with the putative anti-aging compound (2R)-1-(1-benzofuran-2-yl)-N-propylpentane-2-amine ((-)BPAP). GeroScience 2023; published online 12 June 2023 (doi 10.1007/s11357-023-00821-6) · PMID 37306892
• Knoll J. Antiaging compounds: (-)deprenyl (selegeline) and (-)1-(benzofuran-2-yl)-2-propylaminopentane, [(-)BPAP], a selective highly potent enhancer of the impulse propagation mediated release of catecholamine and serotonin in the brain. CNS Drug Reviews 2001;7(3):317-45 · PMID 11607046
• Shimazu S, Miklya I. Pharmacological studies with endogenous enhancer substances: beta-phenylethylamine, tryptamine, and their synthetic derivatives. Progress in Neuro-Psychopharmacology & Biological Psychiatry 2004;28(3):421-7 · PMID 15093948

BPAP — interference & stacking

Bloodwork to run alongside BPAP

Baseline first, then again at 8–12 weeks.

The Brain Fog & Cognition panel covers these in one order — 12 markers, $233.06 with the discount applied.

Check results you already have → · All 103 markers A–Z

BPAP — frequently asked questions

What BPAP is used for

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Related Cognitive & Mood compounds

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