AC-262,536
AC-262536
AC-262,536 (AC-262536) is an investigational nonsteroidal selective androgen receptor modulator (SARM) of the tropanol/azabicyclic chemical class, originally characterized by ACADIA Pharmaceuticals in a 2007 preclinical study. It acts as a partial agonist at the androgen receptor and, in castrated rats, produced anabolic (muscle) effects with comparatively weak androgenic (prostate) effects. There are no human studies of any kind — no clinical trials, no pharmacokinetic data, no safety data, and no published case reports in humans. It is not an approved drug and has never completed human testing. Everything known comes from rodent and cell-based experiments plus equine anti-doping metabolism work. It is an unapproved research chemical with no clinical development pathway; as with SARMs generally, it is prohibited in sport. Because it is sold outside any regulatory oversight, product identity, purity, dose, and contamination are entirely unverified. As with SARMs as a class, the plausible dangers — inferred, not measured for this compound — include suppression of the body's own testosterone production, possible liver injury, cardiovascular strain from adverse lipid changes, and mood disturbance. Anyone using or considering it should understand they are effectively self-experimenting with an unstudied substance and should involve a physician, particularly an endocrinologist, for baseline and follow-up bloodwork.
Mechanism of action
Pharmacokinetics
Not established in humans. No human pharmacokinetic data exist. Human half-life is unknown.
Unknown in humans; no human dosing or duration-of-effect data are available.
Oral administration has been studied in animals; SARMs of this type are typically taken orally. No validated human route or dosing exists.
In horses given oral AC-262,536, the compound underwent phase I metabolism (nine metabolites identified in vitro) and was excreted primarily as glucuronide conjugates in urine and plasma, with an epimer of the parent compound being the longest-detectable marker; parent drug was incorporated into hair. Human metabolism and clearance have not been characterized. This information is presented for monitoring/washout and detection context only, not to guide use.
For monitoring and washout planning, not drug-test evasion.
Physiological & performance effects
- Preclinical (castrated rat) anabolic effect: increased levator ani muscle mass — an androgen-responsive skeletal muscle marker.
- Preclinical partial androgen agonism with comparatively weak effect on prostate and seminal vesicle weight versus testosterone.
- Preclinical suppression of elevated LH in castrated rats (central androgenic feedback).
- No human efficacy data: claimed effects in humans (muscle gain, strength, recomposition) are unverified and rest entirely on animal/mechanistic inference and anecdote, not clinical evidence.
Adverse effects by system
No human data for AC-262,536. By class analogy, SARMs can adversely lower HDL cholesterol and may raise cardiovascular risk, but this has not been measured for this compound. Treat cardiovascular risk as unknown and plausibly present.
No human data for AC-262,536. Hepatotoxicity (transaminase elevation, cholestatic liver injury) has been reported with other SARMs in humans; whether AC-262,536 shares this risk is unstudied. Regard the liver as a plausible target of harm.
No human data for AC-262,536. In castrated rats it suppressed LH, indicating central androgenic activity; in humans, androgenic agonists characteristically suppress the hypothalamic-pituitary-gonadal axis and endogenous testosterone. Suppression is biologically plausible but has never been measured in humans.
No human data for AC-262,536. Given central LH suppression in animals and androgenic mechanism, impaired spermatogenesis, reduced testicular size, and reduced fertility are plausible in humans but unmeasured. Weak prostate/seminal-vesicle effect was seen in rats; human reproductive-tract effects are unknown. Must be avoided in pregnancy — androgens can virilize a female fetus (mechanistic/class concern).
No human data for AC-262,536. Androgenic compounds can affect mood, irritability, aggression, and libido; such effects are plausible but unstudied for this compound.
No human or animal safety data on renal effects for AC-262,536. Renal risk is uncharacterized.
No human data for AC-262,536. Androgens can raise hematocrit/erythropoiesis; whether AC-262,536 does so in humans is unknown and unstudied.
No human data for AC-262,536. Androgen-driven effects such as acne and, in principle, hair changes are theoretically possible given AR agonism, but have not been reported or studied for this compound.
HPTA suppression & recovery
Suppression: Unknown in humans; suppression biologically plausible. In castrated rats AC-262,536 suppressed elevated LH, and androgenic partial agonists characteristically suppress the HPTA in humans — but this has never been measured for this compound in people.
There are no human data on whether, how quickly, or how completely the HPTA recovers after AC-262,536. No recovery protocol can be evidence-based for this compound. Do not self-manage suspected suppression with SERMs or other hormonal agents. Anyone with suppressed testosterone, low libido, fatigue, testicular shrinkage, or infertility concerns after use should consult an endocrinologist for individualized evaluation (LH, FSH, total/free testosterone, estradiol) and management. This monograph does not recommend any post-cycle or single-SERM regimen; recovery decisions belong with a physician.
Monitoring
Cadence: Because no evidence-based schedule exists, involve a clinician: obtain a full baseline before any use, repeat during use if used at all (e.g., within weeks and periodically), and again after stopping until values normalize. Any abnormal result should prompt stopping and medical review.
- Yellowing of skin or eyes, dark urine, right-upper-quadrant abdominal pain, nausea (possible liver injury) — stop and seek urgent care
- Chest pain, breathlessness, palpitations
- Loss of libido, erectile dysfunction, testicular shrinkage, or infertility (HPTA suppression)
- Marked mood change, depression, irritability, or aggression
- Unusual fatigue or swelling
- Severe acne or rapid skin changes
Contraindications
- No human safety testing — cannot be considered safe for anyone; the safest course is non-use.
- Pregnancy and breastfeeding (androgenic mechanism; risk of fetal virilization).
- Anyone trying to conceive or preserve fertility (plausible spermatogenesis/HPTA suppression).
- Personal or family history of hormone-sensitive cancer (e.g., prostate) — AR agonism is theoretically contraindicated.
- Pre-existing liver disease or elevated liver enzymes (plausible hepatotoxic class risk).
- Pre-existing cardiovascular disease or adverse lipid profile (plausible HDL-lowering class risk).
- Adolescents/individuals who have not completed growth and hormonal maturation.
- Use is prohibited in sport under WADA and is detectable in urine, blood, and hair.
Interaction profile
- ModerateWith a thermogenic stimulant: Additive cardiovascular strain
- ModerateWith an anabolic steroid: Hormonal
- ContraindicatedWith DNP: Additive cardiovascular strain
Check a specific combination in the interaction checker.
Reducing harm & when to stop
- The single most important point: AC-262,536 has never been tested in humans. Using it is self-experimentation with an unstudied drug; the lowest-risk choice is not to use it.
- Do not rely on marketing or anecdote — there is no clinical evidence of benefit or safety in people.
- If used despite the risks, get comprehensive bloodwork before starting (testosterone, LH, FSH, estradiol, liver enzymes, lipids, CBC) and involve a clinician.
- Stop immediately and seek medical care for signs of liver injury (jaundice, dark urine, right-upper-quadrant pain), chest pain/breathlessness, or severe mood disturbance.
- Product identity and purity are unverifiable in unregulated research chemicals; contamination and mislabeling are common risks.
- Do not attempt to self-treat suspected testosterone suppression with SERMs or other hormones — see an endocrinologist for individualized management.
- Avoid entirely if pregnant, breastfeeding, trying to conceive, an adolescent, or if you have liver, cardiovascular, or hormone-sensitive cancer risk.
- Detectable in urine, blood, and hair; prohibited in sport under WADA.
Citations (6)
Every clinical claim above is tied to a primary source. Overall evidence grade D — this compound lacks adequate human data; claims rest on preclinical or mechanistic evidence.
- 01
AC-262,536 is a nonsteroidal selective androgen receptor modulator identified as a potent, selective AR ligand with partial agonist activity relative to testosterone.
PreclinicalPharmacological characterization of AC-262536, a novel selective androgen receptor modulator.PMID 18164613 ↗
- 02
In a 2-week study in castrated male rats, AC-262,536 improved anabolic parameters (notably levator ani muscle growth) while having weak androgenic effects on prostate and seminal vesicle weight compared with testosterone.
PreclinicalPharmacological characterization of AC-262536, a novel selective androgen receptor modulator.PMID 18164613 ↗
- 03
AC-262,536 suppressed elevated LH levels in castrated rats, indicating central androgenic feedback activity.
PreclinicalPharmacological characterization of AC-262536, a novel selective androgen receptor modulator.DOI 10.1016/j.jsbmb.2007.11.001 ↗
- 04
Following oral administration to horses, AC-262,536 underwent phase I metabolism and was excreted primarily as glucuronide conjugates in urine and plasma, with an epimer of the parent as the longest-detectable marker and parent drug incorporated into hair.
PreclinicalEquine metabolism of the selective androgen receptor modulator AC-262536 in vitro and in urine, plasma and hair following oral administration.PMID 32959959 ↗
- 05
AC-262,536 (a tropanol-derivative SARM) is included among SARMs detectable in human urine by validated LC-MS methods for anti-doping control.
PreclinicalSimultaneous detection of different chemical classes of selective androgen receptor modulators in urine by liquid chromatography-mass spectrometry-based techniques.PMID 33383501 ↗
- 06
No human clinical, pharmacokinetic, or safety data exist for AC-262,536; all available evidence is preclinical (rodent/cell) or animal anti-doping metabolism work.
PreclinicalPharmacological characterization of AC-262536, a novel selective androgen receptor modulator.PMID 18164613 ↗
Last reviewed 2026-07-06 · Verified against PubMed · Educational, not medical advice