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Research compound — not a dietary supplement
Andarine (S-4) is a research compound, not a regulated dietary supplement. It is sold for research or off-label use. The evidence below is largely preclinical (animal and in-vitro) or early-stage, so no evidence score is assigned. This page is provided for transparency and education — it is not a recommendation to use. Consult a qualified healthcare provider, and be aware that purity, dosing, and legal status vary by jurisdiction.
What the evidence says
Most Andarine (S-4) studies are mechanism or observational rather than RCTs that measure a clinical effect — keep findings provisional.
Most evidence is from mixed-quality studies published 2005–2024.
Based on 6 studies
Confidence
LowBy outcome
Andarine (S-4) has an evidence score of 3.1/10 — emerging evidence based on 6 indexed studies. An early nonsteroidal SARM (S-4 / GTx-007) that was studied preclinically for muscle and bone but NEVER advanced to approval. There are NO human efficacy trials — the anabolic results are from castrated and ovariectomized rats (Gao 2005, Kearbey 2007). It is best known for a distinctive, reversible visual side effect (yellow-tinted vision and impaired night/dark adaptation), it suppresses the body's own testosterone axis, it is banned by the World Anti-Doping Agency, and it is sold only as an unregulated, frequently-mislabeled grey-market research chemical. The honest summary is preclinical-only with real trade-offs. Representative study: PMID 16099859.
The commonly studied dose of Andarine (S-4) is No legitimate or recommended dose — andarine is an unapproved grey-market research chemical with no human efficacy trials, a testosterone-suppressing and vision-disturbing side-effect profile, and a sport ban. We do NOT provide a dosing protocol. Grey-market sources are unregulated and frequently mislabeled, so even the stated content cannot be trusted.. Individual needs vary — start at the lower end of the range and adjust based on how you respond.
Ostarine (MK-2866 / Enobosarm)
Mostly mechanism / observationalA non-steroidal SARM (enobosarm / MK-2866) developed for muscle wasting and cancer cachexia. Real, large randomized trials show it genuinely adds lean body mass — but it has NEVER been approved: the pivotal cancer-cachexia program met its lean-mass endpoints while missing physical-function endpoints, so a durable functional benefit is unproven. Sold widely as a grey-market 'body-recomp' research chemical, it carries documented drug-induced liver injury, HDL/lipid suppression, and testosterone (HPTA) suppression, is banned by WADA, and the products sold online are frequently mislabelled. Real anabolic signal, unproven function, real harms.
Last reviewed June 2026 · evidence from 6 studies · how we score
This information is for educational purposes only. It is not a substitute for professional medical advice. Always consult a qualified healthcare provider before starting, stopping, or changing any supplement or medication.
Andarine (S-4, GTx-007) — nonsteroidal selective androgen receptor modulator
An early nonsteroidal SARM (S-4 / GTx-007) that was studied preclinically for muscle and bone but NEVER advanced to approval. There are NO human efficacy trials — the anabolic results are from castrated and ovariectomized rats (Gao 2005, Kearbey 2007). It is best known for a distinctive, reversible visual side effect (yellow-tinted vision and impaired night/dark adaptation), it suppresses the body's own testosterone axis, it is banned by the World Anti-Doping Agency, and it is sold only as an unregulated, frequently-mislabeled grey-market research chemical. The honest summary is preclinical-only with real trade-offs.
Andarine (S-4) has a coherent tissue-selective anabolic mechanism, but all of its efficacy evidence is preclinical — muscle, bone, and body-fat results come from castrated and ovariectomized rats, with no human efficacy trials of any kind. It suppresses the body's testosterone axis, causes a characteristic reversible visual disturbance, is banned by WADA, and is sold only as an unregulated, frequently-mislabeled grey-market research chemical, so it scores low.
Andarine (development codes S-4 and GTx-007) is an aryl-propionamide nonsteroidal selective androgen receptor modulator (SARM) — one of the first members of the class, characterised by the Dalton/Miller group at GTx/Ohio State in the early 2000s.
SARMs were designed to reproduce the muscle- and bone-anabolic effects of testosterone while sparing the prostate and other strongly androgenic tissues.
In the foundational study (Gao et al. 2005, Endocrinology), S-4 restored soleus muscle mass and strength, levator ani mass, lean body mass, and bone mineral density in castrated male rats to near-intact levels — with only ~16% of the prostate stimulation that DHT produced — demonstrating genuine tissue selectivity.
A companion study (Kearbey et al. 2007, Pharmaceutical Research) showed S-4 maintained bone mineral density and reduced body fat in ovariectomized rats.
Crucially, every one of these efficacy results is an ANIMAL study; there has never been a published human efficacy trial of andarine for muscle, strength, body composition, or any other outcome, and it was not advanced to approval anywhere. Two facts define the honest verdict and keep the score low.
First, the trade-offs are real even in the preclinical data: S-4 suppresses pituitary LH and FSH in a dose-dependent manner (Gao 2005), i.e. it suppresses the hypothalamic-pituitary-testicular axis like other androgens, and andarine is widely and consistently reported to cause a distinctive, reversible visual disturbance — a yellowish tint to vision and impaired adaptation to darkness/night vision — attributed to its action at androgen-receptor-related pathways in the eye.
Second, andarine is not a regulated supplement or an approved medicine: it is on the World Anti-Doping Agency prohibited list at all times (class S1.2 anabolic agents), athletes have been sanctioned for it (Grata 2011), and the material sold online is an unregulated grey-market research chemical.
Independent analyses repeatedly find these products mislabeled — a JAMA study found only 52% of products sold as SARMs actually contained the labeled SARM and many contained unapproved drugs (Van Wagoner 2017), and a 2024 European analysis found contamination, misdosage, and undeclared substances (tamoxifen, clomifene, testosterone, tadalafil) in most products (Gaudiano 2024).
The bottom line: an interesting tissue-selective preclinical androgen with a memorable visual side effect, no human efficacy evidence, HPTA suppression, a doping ban, and grey-market-only, frequently-adulterated sourcing.
S-4 is a nonsteroidal aryl-propionamide that binds the androgen receptor with high affinity and acts as a full agonist in muscle, bone, and pituitary while behaving as only a partial agonist in the prostate — the 'selective' in selective androgen receptor modulator. In castrated rats this produced anabolic muscle and bone effects with minimal prostate stimulation.
In castrated and ovariectomized rodents, S-4 restored skeletal-muscle mass and strength, lean body mass, and bone mineral density and reduced body fat. These are the basis of andarine's body-composition reputation — but they are animal results, never demonstrated in a human efficacy trial.
Like other androgens, S-4 dose-dependently suppresses pituitary LH and FSH (suppressing the body's own testosterone production). Andarine is also distinctively associated with a reversible visual disturbance — a yellow tint to vision and impaired adaptation to darkness — the side effect most users report and the one that most sets it apart from other SARMs.
How Andarine (S-4) works — from molecular targets to health outcomes. Click an edge to see supporting research.This visualization is in beta — pathways are being refined and expanded.
Tap node to isolate • Pinch to zoom • Tap edge for research
No legitimate or recommended dose — andarine is an unapproved grey-market research chemical with no human efficacy trials, a testosterone-suppressing and vision-disturbing side-effect profile, and a sport ban. We do NOT provide a dosing protocol. Grey-market sources are unregulated and frequently mislabeled, so even the stated content cannot be trusted.
Can be taken without food
| Form | Type |
|---|---|
| 💊None — unapproved grey-market research chemical with no human efficacy data | Recommended |
There is no legitimate pharmaceutical form. S-4 is an early SARM research compound; it is not a medicine or a dietary supplement, and it is banned in sport.
Minimum: 1 weeks
Optimal: 1 weeks
Cycling: Not required
Note: No approved or validated timing — there is no human efficacy data, it suppresses the testosterone axis and disturbs vision, and it is banned in sport. This library does not endorse or schedule its use.
Dose-response data unavailable. The current published research for Andarine (S-4) does not provide sufficient dose-specific outcome data to generate reliable dose-response curves.
Refer to the Dosage & Timing section above for recommended dose ranges based on available evidence.
There has never been a human trial showing andarine improves muscle, strength, or body composition. Every anabolic result comes from castrated or ovariectomized rats.
In castrated and ovariectomized rats, S-4 restored muscle mass and strength, lean mass, and bone mineral density and reduced body fat — with minimal prostate effect. A genuine preclinical signal, not demonstrated in people.
Andarine's signature side effect: a reversible yellowish tint to vision and impaired adaptation to darkness or night vision. It typically resolves after stopping, but it is the defining and most consistently reported andarine-specific effect.
S-4 dose-dependently suppresses pituitary LH and FSH, suppressing the body's own testosterone production — an androgenic class effect seen even in the preclinical data.
Andarine is WADA-prohibited at all times and athletes have been sanctioned for it. Sold only as an unregulated research chemical, SARM products are frequently mislabeled, misdosed, or contaminated with other drugs.
Avoid — there is no human efficacy evidence, it suppresses the testosterone axis and disturbs vision, and no quality-controlled product exists.
Avoid absolutely — WADA-prohibited at all times; validated assays detect it and athletes have been sanctioned.
Avoid entirely — an androgen, unstudied in humans.
Additive androgenic effects and compounded suppression of the hypothalamic-pituitary-testicular axis; no human data characterise the combination.
There are essentially no human drug-interaction data for andarine; it was never developed past preclinical work, so interactions are uncharacterised. Grey-market products may also contain undeclared drugs that interact unpredictably.
Tip: The signature andarine side effect — a reversible yellow tint and poor dark adaptation. Typically resolves after discontinuation, but it is a strong reason to avoid the compound, especially before night driving.
Tip: S-4 suppresses LH/FSH dose-dependently. There is no validated human protocol or recovery regimen; suppression and its consequences in people are uncharacterised.
Tip: Independent testing finds many SARM products contain a different SARM, no SARM, or undeclared drugs (e.g. tamoxifen, clomifene, testosterone, tadalafil). There is no quality control; what is actually consumed is unknown.
Timing is flexible for Andarine (S-4) — consistent daily use matters more than the time of day. There is no validated or endorsed human dosing schedule.
Andarine (S-4) should be used with caution — talk to a healthcare provider before taking it. The most commonly reported side effects are yellow-tinted vision / impaired night vision, testosterone-axis (HPTA) suppression, harm from an unregulated, mislabeled, or contaminated product. Use caution if any of these apply to you: Anyone — there are no human efficacy data, it suppresses the body's testosterone axis, and it causes a characteristic visual disturbance; Not an approved medicine and not a regulated dietary supplement — unregulated grey-market research chemical, frequently mislabeled or contaminated; do not self-source; Competitive athletes — banned by WADA at all times; will trigger an anti-doping violation.
LGD-4033 (Ligandrol)
Mostly mechanism / observationalA nonsteroidal SARM with one small Phase-1 human RCT that did show dose-dependent lean-mass gain over 21 days — but at the cost of suppressed testosterone and HDL cholesterol even at low doses. It was never approved as a medicine, multiple case reports tie it to cholestatic liver injury, internet 'SARM' products are routinely mislabelled, and it is banned by the World Anti-Doping Agency. Sold only as an unregulated grey-market research chemical for body composition.