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Adn3.1
Andarine (S-4) Research
Mostly mechanism / observationalLimited safety
6 peer-reviewed studies
What the evidence says
Mostly mechanism / observational
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
Low
By outcome
Androgen axis & hormones
Mostly mechanism / observational6 studies
Muscle & body composition (preclinical)
Too few graded studies2 studies
Bone health
Too few graded studies2 studies
Safety profile
Too few graded studies2 studies
Steady research
1 study in the last 5 years
200520142024
1Animal2005
S-4 (3 and 10 mg/kg) restored soleus muscle mass and strength and levator ani muscle mass to that seen in intact animals ... the strong anabolic effects of S-4 in skeletal muscle, bone, and pituitary were achieved with minimal pharmacologic effect in the prostate.
Gao W, Reiser PJ, Coss CC, Phelps MA, Kearbey JD, Miller DD, et al. · Endocrinology (2005)
The foundational andarine (S-4) study and the basis for its tissue-selectivity reputation — but it is an ANIMAL study in castrated male rats
S-4 restored soleus muscle mass/strength, levator ani mass, lean body mass, and total-body bone mineral density toward intact levels, while returning the prostate to only ~16% of control
S-4 dose-dependently decreased plasma LH and FSH — i.e. it suppresses the pituitary/HPTA axis, an androgenic class effect
Only 52% contained selective androgen receptor modulators and many were inaccurately labeled ... most products contained unapproved drugs and substances.
Van Wagoner RM, Eichner A, Bhasin S, Deuster PA, Eichner D · JAMA (2017)
Counter-evidence on product quality: chemical analysis of 44 products sold online as SARMs (including andarine/S-4)
Only 52% actually contained a SARM; many were inaccurately labeled and contained unapproved drugs and other substances
Directly documents that what is sold as andarine is frequently not andarine, with unknown content and purity
S-4 ... is a novel nonsteroidal androgen agonist that mimics many of the beneficial pharmacologic effects of testosterone with lesser effects on the prostate ... the oral bioavailability of S-4 was 91%.
Perera MA, Yin D, Wu D, Chan KK, Miller DD, Dalton J, et al. · Drug metabolism and disposition: the biological fate of chemicals (2006)
Characterises the pharmacokinetics, metabolism, and disposition of S-4 (andarine) in rats and dogs — the preclinical PK/ADME paper
S-4 showed linear pharmacokinetics with high (91%) oral bioavailability at pharmacologically relevant doses and hepatic phase I/II metabolism
Frames S-4 as the first member of a new tissue-selective androgen class with anabolic specificity in rats
In 23% of samples, the expected SARM was not detected but a different one instead ... Other undeclared pharmaceutical substances (tamoxifen, clomifene, testosterone, epimethandienone, tadalafil) were measured in 30% of samples.
Gaudiano MC, Aureli F, Manna L, Borioni A, Maccelli A, Raimondo M, et al. · Sexual medicine (2024)
Recent (2024) analytical study of 13 SARM products purchased online — reinforces the mislabeling/contamination finding
Qualitative analysis confirmed the stated SARM in only ~70% of samples; 23% contained a different SARM and one contained none; content ranged 30-90% of label claim
30% of products contained undeclared drugs (tamoxifen, clomifene, testosterone, tadalafil) and >60% contained more than one active substance