Androgen & anabolic-receptor signaling

What actually decides this outcome, in order of size

This page is named after a receptor and sells a hormone, and the gap between those two is where most of the disappointment on it lives. Ranked by how much of the outcome each one owns:

1. The training stimulus, because the receptor is not the limiting term until the load is. Androgen receptor content in muscle responds to loading; the hormone acts through a receptor that mechanical work has already put there. Nothing on this list substitutes for that, and the meta-analysis and meta-regression on protein intake and resistance training is the best-evidenced non-hormonal input to this pathway Morton 2018.
2. Whether your testosterone is genuinely low, which is a diagnosis with a defined procedure. Two morning draws, a sensitive assay and gonadotropins, per clinical practice guidance Bhasin 2018. If it is not low, the upstream half of this list is being asked to raise a number that is already adequate, and that is not a smaller effect than the trials showed, it is a different situation from the one they studied.
3. Receptor sensitivity, which varies between people and is measurable. The androgen receptor carries a polymorphic CAG repeat, and repeat length has been studied against clinical phenotypes including premature ovarian failure with X-inactivation weighting Sugawa 2009. Androgen Receptor Sensitivity (CAG Repeat) is the test. It is not a routine order, it is not a treatment decision on its own, and it is the only thing on this page that measures the switch rather than the signal.
4. Where in the total-to-free chain the problem sits. A normal Total Testosterone with a high SHBG (Sex Hormone-Binding Globulin) leaves less at the receptor, and the equations used to estimate the free fraction disagree with each other in a way that depends on the binding protein Hackbarth 2011. SHBG & free testosterone is the pathway for that pattern.
5. What is deliberately absent, which is a structural fact about this page. Selective androgen receptor modulators are not stocked here on a flat rule, so the most direct pharmacology of the receptor this page is named after is missing by choice. An umbrella review of performance-enhancing drugs in healthy athletes is the right document to read about what that class of decision costs and buys Warrier 2023.
6. The one item here with hypertrophy evidence that has nothing to do with androgens. Creatine works through phosphocreatine resynthesis, the loading pharmacokinetics were characterized decades ago Hultman 1996, and the alternative salts have been analyzed for efficacy, safety and cost against monohydrate Escalante 2022. It is the best-evidenced thing on the page and it is not on the page's mechanism.

The order to run these in, and what has to be true first

Load first, measure second, replete third, and treat only what the measurement found. The order is set by what changes the answer to the next question rather than by evidence tier.

1. Progressive loading and adequate protein for twelve weeks before anything on this page. Twelve weeks because that is the interval over which a training response separates from a novelty effect, and because the pooled protein and training evidence is the comparator everything else here has to beat Morton 2018.
2. Two morning draws, then read the gonadotropins. Total Testosterone and SHBG (Sex Hormone-Binding Globulin) on both; one requisition also carrying LH & FSH, Estradiol, Sensitive (LC/MS-MS), Complete Blood Count (CBC) with Differential and Ferritin. The branch is the same one Testosterone & the male hormonal axis makes, and it decides whether the upstream half of this page is even applicable Bhasin 2018.
3. Creatine next, because it is the cheapest real effect available here. Monohydrate unless there is a specific reason, since the alternative forms cost more without a demonstrated advantage Escalante 2022, and a loading phase is a pharmacokinetic choice rather than a requirement Hultman 1996.
4. Then repletion, and only of what is low. Zinc matters through deficiency rather than surplus Prasad 1996; Boron has small human work on binding protein and free testosterone Nielsen 1987; Vitamin D is worth correcting for reasons that are not specific to this pathway. Order Zinc, RBC and Vitamin D (25-Hydroxy) rather than assuming.
5. Tongkat Ali is the herbal with the strongest human file, and it is a binding-protein argument. A systematic review and meta-analysis in men exists Leisegang 2022, and the effect is reported to be largest in stressed and subfertile groups, which is a responder pattern rather than a general claim.
6. Shilajit has a testosterone trial and a purity problem, in that order. Purified resin has human testosterone data Pandit 2016; unpurified material has been assayed for thallium because contamination in this category is documented Kamgar 2025. Buy the purified form or do not buy it.
7. The prescription half is last and is a clinical conversation. Enclomiphene has pharmacodynamic and clinical data in secondary hypogonadism Wiehle 2013; HCG maintains intratesticular testosterone Coviello 2005, which is what preserves fertility; and Triptorelin does the opposite of what this pathway wants if it is used repeatedly rather than once.
8. Fadogia Agrestis is the item on this page with the worst risk-to-evidence ratio. No human trials of any kind, and rodent testicular findings at higher doses. The mechanism argument is a Leydig cell argument; the missing data is the entire human record.

What gets bought for this that cannot move it

The category that fails structurally is the testosterone booster bought by somebody whose testosterone is fine. The herbal and mineral evidence on this page is repletion evidence and responder evidence: zinc through deficiency Prasad 1996, eurycoma with its largest effects in stressed and subfertile men Leisegang 2022, boron in small studies of binding protein Nielsen 1987. A replete man taking all three is running an experiment none of those studies ran.

The surrogate on this page is a serum concentration standing in for receptor activity in a tissue nobody samples. Hypertrophy depends on receptor density, ligand availability at the tissue and the mechanical signal that upregulates both. A blood testosterone measures one of the three, and the free fraction that reaches the receptor has to be estimated with equations that do not agree Hackbarth 2011. That is why Androgen Receptor Sensitivity (CAG Repeat) is interesting even though it changes no protocol: it is the only measurement on the page that is about the receptor.

Two specific misses. Clomiphene works and carries the zuclomiphene fraction, which accumulates and is associated with visual and mood effects; Enclomiphene exists because separating the isomers separates the effects. And Creatine is routinely left out of this pathway because it is not androgenic, which is exactly backwards: it is the item with the most reliable effect on the outcome the page is actually about Hultman 1996.

If the goal underneath is different, so is the page. If the limiting factor is recovery rather than signal, Recovery, sleep & the anabolic window between sessions. If it is local repair after damage, Satellite cells & local repair. If the growth-hormone axis is what is being asked about, GH / IGF-1 axis, which is a different receptor and a different evidence base. And if testosterone is genuinely low, this is a prescription conversation at Testosterone & the male hormonal axis rather than a supplement one Bhasin 2018.

How you would know it was working, on a real read-out and a real timescale

This page makes two predictions. On any effective upstream agent LH & FSH moves before Total Testosterone does, because the pituitary signal is the mechanism and the gonadal response is the consequence Wiehle 2013; and on Creatine body mass rises within the first fortnight without any change in the androgen panel at all, because the mechanism is cell water and phosphate rather than hormone Hultman 1996.

• Total Testosterone with SHBG (Sex Hormone-Binding Globulin), morning, twice at baseline and once at 8 weeks. Eight weeks because steroidogenic output takes weeks rather than days to reach a new set point, and always the same laboratory, because assay differences exceed the change being looked for.
• Free Testosterone calculated from that pair, and read as a personal trend. The equations disagree across the binding-protein range Hackbarth 2011, so the number is useful against your own previous number and not against a published cutoff.
• LH & FSH at baseline and 4 weeks on any upstream agent. This is the mechanism check. Gonadotropins that have not moved mean the agent is not doing what the page says it does Wiehle 2013.
• Complete Blood Count (CBC) with Differential and Estradiol, Sensitive (LC/MS-MS) at baseline and 3 months on anything that raises testosterone. Hematocrit is the commonest reason a protocol is changed, and it moves on a slower schedule than the hormone.
• Androgen Receptor Sensitivity (CAG Repeat) once, if you want to know it, and never as a reason to start something. It is a sensitivity measurement rather than a treatment threshold Sugawa 2009, and it does not change from year to year.
• A fixed strength test every four weeks, same lift, same rest, same time of day. This is the endpoint the page is actually about, and it is the one nobody measures.

What will fool you. Testosterone falls after poor sleep, during illness and through the afternoon, so a draw can manufacture both the problem and the improvement. Creatine adds intracellular water in the first weeks, which reads as lean mass on a scale and on most impedance devices Hultman 1996. Beginning a new training block at the same time as a supplement makes the two inseparable, which is why the twelve-week loading period comes first. Biotin interferes with several hormone immunoassays. And an unlicensed vial of anything on the prescription half of this page has no assay behind it, so a null result may be a product result Kamgar 2025.

Sources read for these sections

• Bhasin S. Testosterone Therapy in Men With Hypogonadism: An Endocrine Society Clinical Practice Guideline. Journal of Clinical Endocrinology and Metabolism 2018;103(5):1715-1744 · PMID 29562364
• Sugawa F, et al. Premature ovarian failure and androgen receptor gene CAG repeat lengths weighted by X chromosome inactivation patterns. Fertility and Sterility 2009 · PMID 18281036
• Hackbarth JS, et al. Accuracy of calculated free testosterone differs between equations and depends on gender and SHBG concentration. Steroids 2011 · PMID 20816687
• Leisegang K. Eurycoma longifolia (Jack) Improves Serum Total Testosterone in Men: A Systematic Review and Meta-Analysis of Clinical Trials. Medicina (Kaunas) 2022;58(8):1047 · PMID 36013514
• Prasad AS, et al. Zinc status and serum testosterone levels of healthy adults. Nutrition, 1996 · PMID 8875519
• Nielsen FH, et al. Effect of dietary boron on mineral, estrogen, and testosterone metabolism in postmenopausal women. The FASEB Journal, 1987 · PMID 3678698
• Hultman E, et al. Muscle creatine loading in men. Journal of Applied Physiology, 1996 · PMID 8828669
• Escalante G. Analysis of the efficacy, safety, and cost of alternative forms of creatine available for purchase on Amazon.com: are label claims supported by science?. Heliyon 2022 · PMID 36544833
• Morton RW. A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength in healthy adults. British Journal of Sports Medicine 2018;52(6):376-384 · PMID 28698222
• Warrier AA. Performance-Enhancing Drugs in Healthy Athletes: An Umbrella Review of Systematic Reviews and Meta-analyses. Sports Health 2023 · PMID 37688400
• Pandit S, et al. Clinical evaluation of purified Shilajit on testosterone levels in healthy volunteers. Andrologia 2016 · PMID 26395129
• Kamgar E, et al. Quantifying of thallium in Shilajit and its supplements to unveil the potential risk of consumption of this popular traditional medicine. BMC Chemistry 2025 · PMID 39827344
• Wiehle R, Cunningham GR, Pitteloud N, Wike J, Hsu K, Fontenot GK, Rosner M, Dwyer A, Podolski J. Testosterone Restoration by Enclomiphene Citrate in Men with Secondary Hypogonadism: Pharmacodynamics and Pharmacokinetics.. BJU Int 2013 · PMID 23875626
• Coviello AD, et al. Low-dose human chorionic gonadotropin maintains intratesticular testosterone in normal men with testosterone-induced gonadotropin suppression. Journal of Clinical Endocrinology and Metabolism 2005 · PMID 15713727