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Adn3.1
Andarine (S-4) Research
Mostly mechanism / observational
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 confidence
By outcome
Androgen axis & hormones
Mostly mechanism / observational6 studies
Muscle & body composition (preclinical)Muscle and bone gains shown in rodents; no human efficacy data — anabolic effect is unproven in people. · Not established (no human trials)
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
1Observational2017
In plain English: 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
In plain English: 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
In plain English: 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
In plain English: S-4 treatment maintained whole body and trabecular BMD, cortical content, and increased bone strength while decreasing body fat in these animals.
Kearbey JD, Gao W, Narayanan R, Fisher SJ, Wu D, Miller DD, et al. · Pharmaceutical research (2007)
Second foundational S-4 study, in an ovariectomy-induced model of accelerated bone loss — again an ANIMAL study (female Sprague-Dawley rats)
S-4 maintained whole-body and trabecular bone mineral density and cortical content, increased bone strength, and decreased body fat
Extends the preclinical anabolic profile from muscle to bone and fat, reinforcing the tissue-selective mechanism
In plain English: 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