Cabergoline
Dostinex
Cabergoline (Dostinex) is a hormonal & sexual research compound. Long-acting dopamine D2 receptor agonist. Dopamine is the physiological brake on prolactin, so a D2 agonist shuts prolactin secretion down at the pituitary.
Cabergoline quick facts
| Reported research dose | 0.25–0.5mg twice weekly |
| Route | Oral |
| Frequency | 2x |
| Half-life | ~63–68 hours — the reason it's dosed twice a week rather than daily. |
| Forms | Oral |
| Evidence level | Approved for hyperprolactinemia and prolactinoma; large human dataset |
Used to correct prolactin elevation from 19-nor compounds or a prolactinoma. ⚠️ Two real risks people underrate: valvular heart disease at the higher doses used in Parkinson's, and impulse-control disorders — compulsive gambling, spending, hypersexuality — which are documented and can be severe. Confirm prolactin is actually high before treating it. Do not use it recreationally for the sexual side effects.
How Cabergoline works
Long-acting dopamine D2 receptor agonist. Dopamine is the physiological brake on prolactin, so a D2 agonist shuts prolactin secretion down at the pituitary.
Proposed benefits
Researched for libido, hormonal signaling and reproductive / sexual function.
Where to get Cabergoline
Buy Cabergoline at AlgoRx →The evidence for Cabergoline
Graded by what exists behind each claim.
✅ Clinically validated
- A licensed drug with strong trial data for hyperprolactinemia and prolactinoma, where it reliably normalizes prolactin and shrinks tumors — outperforming bromocriptine in head-to-head trials.
- The valve issue is real and dose-dependent: cardiac valvulopathy was documented at the high doses used in Parkinson's disease, which is why those indications were restricted. Endocrine doses are roughly an order of magnitude lower and the risk at that level appears very small — but echocardiographic monitoring on long-term use is standard for a reason.
📊 Correlative data
- Used off-label for prolactin-related sexual dysfunction and alongside compounds that raise prolactin. Reported experience includes nausea and hypotension early, and mood changes including impulse-control effects in a minority — the latter is a documented dopaminergic class effect.
🧪 Theoretical / extrapolated
- A long-acting D2 dopamine receptor agonist. Dopamine is the physiological brake on prolactin, so agonizing D2 suppresses it.
- The same D2 activity predicts the rest of the profile — nausea via the chemoreceptor trigger zone, hypotension, and the impulse-control effects that follow from dopaminergic signaling in reward pathways.
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 Cabergoline actually does
Cabergoline is an ergot alkaloid, and that single structural fact explains both why it works twice a week and why it has a heart warning. The ergoline scaffold is a rigid tetracyclic system that happens to present the same pharmacophore as several monoamines — so an ergoline drug is almost never selective for one receptor family, and cabergoline is not.
The intended target: the D2 receptor on the pituitary lactotroph. Prolactin is unique among pituitary hormones in being under tonic inhibition. Dopamine released from tuberoinfundibular neurons travels down the hypophyseal portal system and acts on D2 receptors on lactotrophs. D2 couples to Gi: it lowers cyclic AMP, closes calcium channels and opens potassium channels, hyperpolarizing the cell. The consequences are sequential — prolactin secretion falls within hours, prolactin gene transcription falls over days, and lactotroph size falls over weeks. That last one is why a dopamine agonist shrinks a tumor rather than merely masking its output, and it is the reason drugs compete with surgery for prolactinoma Cai 2022.
Why the dosing interval is days rather than hours. The card gives roughly 63–68 hours, which is extraordinary for a small molecule. Two things produce it: slow elimination, and unusually tight, slowly reversible binding to pituitary D2 receptors, so the tissue effect outlasts the plasma concentration. The dosing interval is set by receptor occupancy, not by plasma clearance — the same distinction finasteride illustrates from the enzyme side.
The off-target that matters, and it is a receptor, not a toxicity. Ergolines have affinity at 5-HT2B serotonin receptors. 5-HT2B is expressed on cardiac valve interstitial cells, and agonism at it drives fibroblast proliferation and deposition of matrix on the valve leaflets, producing a thickened, poorly coapting valve and regurgitation. This is the identical mechanism that removed fenfluramine and pergolide from the market, and it is why an entire joint position statement from three cardiology and endocrine societies exists purely to say who should have an echocardiogram and when Steeds 2019. A tricuspid case has been reported at prolactinoma dosing Hayes 2023.
The dose separation is the whole safety argument. The valvulopathy signal was established at the high, daily doses used in Parkinson's disease. Prolactinoma doses are a fraction of that and given twice weekly. The risk is not zero and it is not the Parkinson's risk, and treating those two statements as the same statement is the commonest error made about this drug.
Cell, rodent, human — and where it stops
Step one, receptor pharmacology: settled. D2 agonism at the lactotroph, Gi coupling, and the sequence secretion → transcription → cell size is standard neuroendocrinology and is the basis of every guideline below.
Step two, humans, and the endpoint is two endpoints. A scoping review examined the indications, effectiveness and limitations of cabergoline for radiological and biochemical remission of prolactinomas Mishra 2021. Those are two different questions — is the hormone normal, and has the tumor shrunk — and a drug can achieve one without the other. That the review had to name both separately is the informative part.
Step three, against the alternative. A systematic review and meta-analysis asked whether dopamine agonists are still first-choice for prolactinoma in the era of endoscopic surgery Cai 2022. That this is a live question in 2022 tells you the drug is good rather than perfect: a proportion of people are resistant or intolerant, and for them a transsphenoidal operation is a real competitor rather than a fallback.
Step four, a guideline that states what to do with the answers. The Italian guidelines for the management of prolactinomas Cozzi 2023 are the kind of document that turns trial results into thresholds — when to treat, what remission means, when withdrawal can be attempted — and the existence of national guidelines is itself evidence that this is a managed clinical condition rather than a supplement decision.
Step five, the safety monitoring, which has its own document. A joint position statement of the British Society of Echocardiography, the British Heart Valve Society and the Society for Endocrinology sets out echocardiographic monitoring for people on dopamine agonist therapy for hyperprolactinemia Steeds 2019. A whole guideline about one imaging test for one drug class is the strongest possible statement that the risk is taken seriously, and it is also the reason this drug does not belong in an unsupervised stack.
Where the chain breaks. (1) Almost all of this evidence is in people with prolactinomas or hyperprolactinemia. None of it is in people with normal prolactin taking cabergoline for other reasons, which is the use this Vault's readers are most likely to encounter. (2) The valvulopathy literature is dominated by Parkinson's-dose exposure, so the risk at low intermittent doses is estimated rather than measured. (3) Impulse-control disorders on dopamine agonists are documented mostly in Parkinson's cohorts, again at higher doses. (4) There is no randomized trial of cabergoline in anybody without a pituitary indication.
What would have to be true, and how you would know it was not
Three predictions. The first is measurable in a fortnight, the second is the one that decides whether the drug is doing anything useful, and the third is the imaging test that cannot be skipped.
1. If D2 receptors are being occupied, prolactin falls fast and far. Prolactin at baseline and at 4 weeks. The mechanism predicts a large drop — secretion is under tonic inhibition, so adding an agonist removes the brake's opposition immediately. If prolactin has not moved at 4 weeks, either the dose is wrong, the product is wrong, or the raised prolactin was never dopamine-responsive, and macroprolactin or a stalk-compression picture belongs in that differential rather than a higher dose.
2. The point of lowering prolactin is the gonadal axis, and that is where the benefit shows. High prolactin suppresses GnRH pulsatility and therefore gonadotropins. So the downstream prediction is: total testosterone and free testosterone rise in men, estradiol and cycle regularity recover in women, and both take longer than prolactin does — 8 to 12 weeks, because the axis has to restart rather than merely disinhibit. If prolactin normalizes and testosterone does not follow within three months, prolactin was not the reason it was low. That is a genuinely falsifying result and it is the one most likely to be ignored.
3. The measurement that is not a blood test. Baseline echocardiography before or shortly after starting, and repeat imaging on the schedule a clinician sets, is what the joint position statement exists to specify Steeds 2019. Valvular regurgitation is silent until it is severe; there is no symptom that warns you and no blood marker that stands in for the image. New breathlessness on exertion or ankle swelling in somebody on an ergoline is an echocardiogram, not a coincidence Hayes 2023.
What nobody has tested yet
Four things nobody has established, and the first is the one that matters to most people who search for this drug.
Nobody has run a randomized trial of cabergoline in people with normal prolactin. Every trial above is in hyperprolactinemia or prolactinoma Mishra 2021 Cozzi 2023. The uses this compound is sought for outside that indication rest entirely on extrapolating a mechanism into a population it was never measured in, and this page will keep saying so until the trial exists.
Nobody has quantified valvular risk at low intermittent dosing. The monitoring guidance exists Steeds 2019 because the risk is plausible, not because the incidence at prolactinoma doses is known. A prospective echocardiographic cohort with quantified cumulative dose is the study, it would take years, and it has not been done at the scale required.
Nobody has predicted resistance in advance. A minority of prolactinomas do not respond, which is why surgery remains a real comparator Cai 2022. Whether D2 receptor density, receptor isoform expression or tumor genotype predicts that resistance before a course is started is unanswered, and answering it would spare non-responders months of exposure.
Nobody has settled the withdrawal question with a clean trial. Guidelines discuss attempted withdrawal after prolonged remission Cozzi 2023. Which people stay in remission off drug, and which relapse, is described observationally rather than predicted. A randomized withdrawal study stratified by residual tumor size on imaging is an obvious design nobody has published.
Cabergoline — its own safety story, not its class's
Cabergoline is a prescription medicine whose specific risk is a structural property of the ergot ring, so the generic block above does not cover it.
Cardiac valve disease is the risk that has its own guideline. 5-HT2B agonism on valve interstitial cells drives fibrotic thickening and regurgitation. The joint position statement from the British Society of Echocardiography, the British Heart Valve Society and the Society for Endocrinology sets out who is imaged and how often Steeds 2019, and cabergoline-associated tricuspid valvulopathy has been reported in prolactinoma treatment Hayes 2023. The risk is dose- and duration-dependent, it is far better established at Parkinson's doses than at prolactinoma doses, and the only way to detect it early is an image.
Fibrosis is not limited to the valve. Ergolines have been associated with pleural, retroperitoneal and pericardial fibrosis. New breathlessness, pleuritic pain, flank pain or leg swelling in somebody on long-term therapy belongs in that differential rather than being explained away.
Impulse-control disorders are a dopamine agonist class effect. Pathological gambling, compulsive shopping, hypersexuality and binge behavior are documented across D2/D3 agonists. The person taking the drug is usually the last to notice, which is why this is a warning that should be given to a partner or family member as well as to the patient. It is reversible on dose reduction or withdrawal.
The first-dose effects are orthostatic. Dizziness, nausea and postural hypotension are commonest at initiation and with dose increases, which is the reason clinical practice starts low and goes up slowly, and the reason the first dose is not taken before driving.
Psychiatric history changes the calculation. Dopamine agonism can precipitate or worsen psychosis. In anybody with a psychotic illness this is a specialist decision.
What this page will not do. Recommend a dose, or treat cabergoline as a stack component. It is a pituitary drug with a cardiac imaging requirement attached Steeds 2019, and national guidelines exist for exactly the population it was studied in Cozzi 2023. Using it outside that population means using it outside all of the evidence on this page.
Sources read for this page
- Mishra R, et al. A scoping review to understand the indications, effectiveness, and limitations of cabergoline in radiological and biochemical remission of prolactinomas. Indian Journal of Endocrinology and Metabolism 2021 · PMID 35355923
- Cozzi R, et al. Italian Guidelines for the Management of Prolactinomas. Endocrine, Metabolic and Immune Disorders Drug Targets 2023 · PMID 37171003
- Cai X, et al. Are dopamine agonists still the first-choice treatment for prolactinoma in the era of endoscopy? A systematic review and meta-analysis. Chinese Neurosurgical Journal 2022 · PMID 35395837
- Steeds RP, et al. Echocardiography and monitoring patients receiving dopamine agonist therapy for hyperprolactinaemia: a joint position statement of the British Society of Echocardiography, the British Heart Valve Society and the Society for Endocrinology. Echo Research and Practice 2019 · PMID 30825409
- Hayes AG, et al. Cabergoline-associated valvulopathy of the tricuspid valve in the treatment of prolactinoma. Endocrine Oncology 2023 · PMID 37434646
Cabergoline — safety, predicted from mechanism
Predicted from mechanism, not from a human safety trial. How that reasoning works →
What the mechanism predicts
Derived from the molecule, not a trial.
- This group acts directly on established CNS receptors — GABA-B (phenibut), serotonergic and histaminergic (trazodone, doxepin), beta-adrenergic (propranolol), dopaminergic (cabergoline, apomorphine). These are pharmacological drugs, not research peptides, and the predicted problems are the known ones for each receptor.
- Phenibut is the one that needs saying plainly: it is physically addictive. GABA-B agonism produces tolerance within days of regular use, and withdrawal is genuinely severe — anxiety, insomnia, tremor, and in heavy users, psychosis and seizures. It is closer to a benzodiazepine than to a nootropic in this respect, and it is sold as though it were the latter.
- Propranolol blunts the physical symptoms of adrenaline. That predicts the useful effect and also the problem — it blunts the training response and masks hypoglycemia.
- Dopamine agonists predict nausea, orthostatic hypotension and, at the doses used in Parkinson's, impulse-control problems. Cabergoline's half-life is very long, so effects persist well past a dose.
What has actually been reported
- Phenibut dependence and withdrawal are well documented in case reports and poison-center data.
- Trazodone: sedation, orthostatic hypotension, and rarely priapism — which is a medical emergency.
- Abrupt propranolol cessation causes rebound tachycardia and hypertension. Do not stop a beta-blocker suddenly.
- Cabergoline at high cumulative doses is associated with cardiac valve changes; at the low doses used for prolactin this has not been shown.
How to reduce the risk
Same mechanism as the prediction.
- For phenibut, the only reliable mitigation is frequency: occasional use does not produce dependence, regular use does. There is no dose that makes daily use safe.
- Taper anything in this group rather than stopping abruptly.
- Take the first dose of anything with orthostatic effects at home, sitting down.
What it does to your bloodwork
A fact about the assay.
- Prolactin if using cabergoline (it is usually why you are). Otherwise blood pressure and heart rate are the monitoring that matters.
Don't run this if
- You already take a sedative, a benzodiazepine, or drink regularly — the CNS depressant effects are additive and this is where respiratory depression comes from.
- You are on an antidepressant and considering trazodone — serotonergic combinations need a prescriber, not a forum.
The honest unknown
- Most of this group is well characterized for its licensed use. What is NOT characterized is the off-label use most people here are making of it, at doses and durations nobody studied.
Not medical advice. If you take prescription medication or have a diagnosed condition, check this with a pharmacist or doctor.
Cabergoline — interference & stacking
Predicted from mechanism, not from an interaction study. How mechanism-predicted claims are made →
What Cabergoline moves on your bloodwork
Expected direction, not a measured one.
- Comprehensive Metabolic Panel (CMP) — ◆ worth watching
Most of this class has no predicted marker movement at all, and saying so is more useful than listing markers that will not move.
What to do: A baseline liver panel is reasonable for anything taken daily and long-term. Beyond that there is nothing specific to chase.
- How to work up to it, and when not to
- When to take it, and why that window
- Cycle length
- Time off between cycles
- Fasted or fed, and when in the day
- Coach Cam's personal notes
- Which compounds push the same lever, and why the dose adds up faster than people count
- What blunts it — the stacks that waste your money
- What compounds the risk, so a side effect arrives sooner than any one of them suggests
- Coach Cam's read on running it alongside the rest of your protocol
Everything above is free and stays free. Skool is where it becomes a plan — Cabergoline in an order, with the rest of what you're running.
Unlock in Skool — $10/mo →Bloodwork to run alongside Cabergoline
Baseline first, then again at 8–12 weeks.
| Marker | What it’s watching for |
|---|---|
| Total Testosterone | The baseline you can't reconstruct later |
| Free Testosterone | The fraction that does anything — total alone misleads |
| SHBG (Sex Hormone-Binding Globulin) | Explains a normal total sitting on top of a low free |
| Estradiol, Sensitive (LC/MS-MS) | The other half of the ratio, and the source of most symptoms |
| LH & FSH | Separates a testicular problem from a pituitary one |
The “Low T? Rule Out the Reversible Causes First” panel covers these in one order — 11 markers, $211.50 with the discount applied.
Check results you already have → · All 103 markers A–Z
Cabergoline — frequently asked questions
What is Cabergoline?
Cabergoline (Dostinex) is a hormonal & sexual research compound. Long-acting dopamine D2 receptor agonist. Dopamine is the physiological brake on prolactin, so a D2 agonist shuts prolactin secretion down at the pituitary.
Is the full Cabergoline protocol on this page?
The reported research dose is on this page, along with how Cabergoline works and the evidence behind it. The protocol — how to work up to it, frequency, cycle length, time off, what not to stack it with and Coach Cam's notes — is inside Skool.
What is the half-life of Cabergoline?
Cabergoline has an approximate half-life of ~63–68 hours — the reason it's dosed twice a week rather than daily., which is part of what determines how often it's dosed.
What's the evidence behind Cabergoline?
Current evidence level: Approved for hyperprolactinemia and prolactinoma; large human dataset. Cabergoline is offered for research purposes only and is not an approved medicine.
Cabergoline inside a finished plan
One arm of 1 Protocol Blueprint, free to read in full.
What Cabergoline is used for
Cabergoline appears under 2 goals in the goal router.
Related Hormonal & Sexual compounds
Where this goes next
Cabergoline is the central arm of this plan. The page above is the free breakdown of one compound; the plan it belongs to — the dosing, the order to correct things in, the week-by-week schedule and what to retest — is a lesson inside Skool.