Androgen Receptor Modulators (SARMs)
AC-262536
AC-262,536; AC-262; AC262536; AC 262536
8 min read · Updated July 10, 2026 · 6 references
Curated by PeptideInfo Wikilast reviewed how we verify
AC-262536 is a nonsteroidal SARM (partial agonist at the androgen receptor), not a peptide and not an approved medicine. All data come from a single 2008 preclinical study (PMID 18164613): high AR affinity (Ki ~5 nM), tissue-selective anabolic effect in castrated rats, LH suppression, and anti-proliferative activity on LNCaP cells in vitro. No human data exist. It carries the SARM class warnings (liver injury, testosterone/HPTA suppression) and is banned by WADA.
Evidence: Evidence is largely animal/cell studies, not humans.
- Nonsteroidal SARM and partial agonist at the androgen receptor — not a peptide
- Not an approved medicine anywhere; a preclinical research chemical only
- All data trace to a single 2008 ACADIA study (PMID 18164613); no human trials identified
- High AR affinity (Ki ~5 nM) and selective over a 47-nuclear-receptor panel [In vitro]
- Tissue-selective: ~66% of testosterone's levator-ani effect at ~27% of its prostate effect in castrated rats [Animal]
- Reduced plasma LH in castrated rats — mechanistic basis for HPTA/testosterone suppression [Animal]
- Carries SARM-class warnings — FDA-flagged liver injury (incl. acute liver failure) and testosterone suppression
- Prohibited in sport by WADA (S1.2, Other Anabolic Agents)
- Not a milder, safer, or legal alternative to anabolic steroids
AC-262536 is a nonsteroidal selective androgen receptor modulator (SARM) that acts as a partial agonist at the androgen receptor. It is not a peptide and is not an approved medicine anywhere — it exists only as a preclinical research chemical, characterized in a single published animal/in-vitro study (PMID 18164613, J Steroid Biochem Mol Biol 2008) from ACADIA Pharmaceuticals. In castrated rats it produced roughly 66% of testosterone's anabolic (levator ani) effect at only ~27% of its prostate (androgenic) effect, reduced plasma LH, and inhibited DHT-driven proliferation of LNCaP prostate-cancer cells in vitro. There is no human efficacy or safety data of any kind, and it is prohibited in sport by WADA (S1.2). It is not an approved medicine and has never entered published human trials.
Overview
AC-262536 (also written AC-262,536) is a nonsteroidal selective androgen receptor modulator (SARM) that acts as a partial agonist at the androgen receptor (AR). It is not a peptide — it is a small synthetic molecule — and it is not an approved medicine anywhere in the world.
Everything currently known about AC-262536 traces back to a single published preclinical study: Piu et al., Journal of Steroid Biochemistry and Molecular Biology, 2008 (PMID 18164613), from ACADIA Pharmaceuticals. That paper characterized the compound in binding assays, cell-based assays, and castrated-rat models. There are no published human trials, and it does not appear to have advanced beyond that early characterization.
Preclinical research chemical — no human data, not a steroid alternative
AC-262536 has never been studied in humans. Every claim below is from animal or in-vitro work. As a member of the SARM class, it carries the FDA-flagged risks of the class — including serious liver injury (up to acute liver failure) and suppression of the body's own testosterone (HPTA axis). It is prohibited in sport by WADA. It is not a milder, safer, or legal alternative to anabolic steroids. This page is educational only and is not medical or legal advice, and it does not provide dosing or protocols. (Dated 2026-07-10.)
Chemistry and structure
| Property | Value |
|---|---|
| Name | AC-262536 |
| Class | Nonsteroidal selective androgen receptor modulator (SARM) — small molecule, not a peptide |
| Molecular formula | C18H18N2O |
| Molecular weight | 278.35 g/mol (PubChem: 278.3) |
| CAS number | 870888-46-3 |
| PubChem CID | 44512434 |
| IUPAC name | 4-(3-endo-hydroxy-8-azabicyclo[3.2.1]oct-8-yl)naphthalene-1-carbonitrile |
Structurally, AC-262536 belongs to an aniline / azabicyclooctane class related to ACADIA's ACP-105 and, more loosely, to RAD140 (testolone). PubChem confirms the identity as 4-(3-endo-hydroxy-8-azabicyclo[3.2.1]oct-8-yl)naphthalene-1-carbonitrile (C18H18N2O, CID 44512434).
The variants AC-262,536, AC-262, AC262536, and AC 262536 all refer to the same molecule. AC-262536 is a defined synthetic small molecule, not a peptide sequence.
Mechanism of action
AC-262536 works by binding and partially activating the androgen receptor. Its defining feature — like other SARMs — is tissue selectivity: relatively strong action on muscle-type (anabolic) tissue and weaker action on prostate-type (androgenic) tissue. All of the following is preclinical.
- Androgen receptor — partial agonist [In vitro]. Binds the AR with high affinity (Ki ~5 nM) and activates it partially relative to testosterone. It was selective for the AR across a panel of 47 nuclear receptors, with no significant affinity for the others tested. (Source: PMID 18164613.)
- Muscle (levator ani) vs prostate — tissue selectivity [Animal]. In castrated rats it produced ~66% of testosterone's maximal levator-ani (anabolic) effect but only ~27% of its maximal prostate (androgenic) effect — the defining SARM tissue-selectivity profile. (Source: PMID 18164613.)
- HPTA axis — central suppression [Animal]. It reduced elevated plasma luteinizing hormone (LH) in castrated rats, indicating central negative feedback on gonadotropin signaling. This is the mechanistic basis for the HPTA / testosterone suppression seen across the SARM class. (Source: PMID 18164613.)
- LNCaP prostate-cancer cells — anti-proliferative [In vitro]. It inhibited dihydrotestosterone (DHT)-induced proliferation of androgen-sensitive LNCaP prostate cancer cells at 0.1 and 1 µM in vitro. (Source: PMID 18164613.)
A tidy preclinical mechanism is not evidence of human benefit or human safety. Tissue selectivity in castrated rats does not establish that AC-262536 is safe, effective, or "prostate-sparing" in people — that has never been tested.
Research and evidence
| Finding | Model | Year | Source |
|---|---|---|---|
| High-affinity, selective AR binding (Ki ~5 nM; selective over a 47-receptor nuclear panel) | In vitro | 2008 | Piu et al., PMID 18164613 |
| Tissue-selective anabolic profile: ~66% of testosterone's levator-ani effect at ~27% of its prostate effect | Animal (2-week chronic study, castrated male rats) | 2008 | Piu et al., PMID 18164613 |
| Reduced elevated plasma LH (central suppression) | Animal (castrated rats) | 2008 | Piu et al., PMID 18164613 |
| Inhibited DHT-induced LNCaP prostate-cancer cell proliferation (0.1 and 1 µM) | In vitro | 2008 | Piu et al., PMID 18164613 |
| No human efficacy data of any kind | Human — none | — | No clinical trials identified (ClinicalTrials.gov / PubMed) |
Honestly stated: the entire evidence base for AC-262536 is one 2008 preclinical paper. It shows an interesting tissue-selective anabolic signature in castrated rats and clean AR selectivity in vitro — but there is no human efficacy or safety data of any kind, and development does not appear to have progressed to published human trials.
Status and regulation
- Preclinical only. No human trials identified on ClinicalTrials.gov or PubMed. AC-262536 is not in clinical development in any indication that these sources record.
- Not an approved medicine. It is not approved by the FDA, EMA, or any other regulator, and has no approved indication.
- Research reagent framing. Where AC-262536 is sold, it is sold as a research chemical ("not for human consumption"). That framing does not make human use safe or lawful.
- Prohibited in sport. It is banned by WADA under S1.2 (Other Anabolic Agents — SARMs) at all times, and USADA lists SARMs as a prohibited anabolic class.
Safety
AC-262536 has no human safety data. The signals below are either compound-specific but animal-only, or class-level for SARMs.
- No human safety data [Human]. AC-262536 has never been studied in humans. Any statement that it is "safe" is unknown, not reassuring — untested is not the same as safe.
- SARM-class liver injury / DILI [Human — class-level]. The FDA has warned that products containing SARMs are associated with serious liver injury, including cases requiring hospitalization and acute liver failure. This is a class-level signal; AC-262536 itself has no human liver-safety data. (Source: FDA SARM consumer warning.)
- Testosterone / HPTA suppression [Animal — compound; Human — class]. AC-262536 reduced plasma LH in castrated rats, consistent with central suppression of the HPTA axis. Across the SARM class this manifests as suppression of the body's own testosterone; the extent in humans is unknown for this specific compound.
- Broader SARM-class adverse events [Human — class-level]. SARM use as a class has been linked in FDA communications and case reports to increased risk of heart attack or stroke, psychiatric effects, sexual dysfunction, infertility, and testicular shrinkage — not specifically demonstrated for AC-262536, but relevant to anyone exposed to a product labelled as a SARM.
What is actually in a product labelled "AC-262536"?
A JAMA analysis of products sold online as SARMs (Van Wagoner et al., JAMA 2017;318(20):2004-2010, PMID 29183075) found that only 52% actually contained the labelled SARM, 39% contained a different unapproved drug, and 9% contained no active drug at all. A label reading "AC-262536" is therefore not a reliable statement of what the vial contains. Combined with the total absence of human data, real-world exposure carries unquantifiable risk. Not medical advice.
Legal status
AC-262536 is best understood as a research-reagent-classified compound: it is not an approved medicine, and in most jurisdictions selling or using an unapproved compound in humans falls under unauthorised-medicine rules. This page does not assess the legality of any particular use in any particular country. Separately — and on a different axis from legality — AC-262536 is prohibited in sport by WADA under S1.2 (Other Anabolic Agents). Being on the WADA list governs sport eligibility, not general legality. Nothing here is legal advice (dated 2026-07-10).
How it compares
AC-262536 sits in the same nonsteroidal SARM bucket as several better-known compounds. The honest distinction is evidence stage: AC-262536 is purely preclinical, whereas some peers at least reached early human trials.
| Compound | What it is | Stage | Notes |
|---|---|---|---|
| AC-262536 | Nonsteroidal SARM, AR partial agonist (not a peptide) | Preclinical — one 2008 study | Tissue-selective in castrated rats; no human data |
| Testolone (RAD140) | Nonsteroidal SARM | Early human trials (oncology) | Structurally related class; still not an approved medicine |
| Ostarine (MK-2866) | Nonsteroidal SARM | Multiple human trials | The most-studied SARM; still not approved; WADA-banned |
Takeaways:
- Same class, different maturity. AC-262536 is the least-studied of these — a single preclinical paper versus human-trial data for ostarine and testolone.
- None is approved. No SARM here is an approved medicine, and all are WADA-prohibited.
- No "prostate-sparing" claim in humans. The tissue selectivity is a rat/in-vitro finding for AC-262536 — not a demonstrated human safety property.
Common misconceptions
- "AC-262536 is a peptide." No. It is a nonsteroidal small molecule (C18H18N2O), a SARM. It is listed here because SARMs are frequently discussed alongside peptides in muscle/performance contexts.
- "It's an approved or clinically proven drug." No. It is a preclinical research chemical with one 2008 study and zero human trials.
- "It's a safer, milder, or legal alternative to steroids." No. It carries the SARM-class liver and HPTA-suppression warnings, has no human safety data, and is WADA-banned.
- "The prostate-sparing profile means it's safe." That profile is a castrated-rat / in-vitro result — it says nothing verified about human safety.
- "A vial labelled AC-262536 contains AC-262536." Often not — the JAMA analysis found the label was wrong about half the time.
This entry is strictly educational and encyclopedic. It is not medical, legal, or pharmaceutical advice, and it intentionally does not provide dosing protocols, administration instructions, or sourcing information.
References
- 1.Pharmacological characterization of AC-262536, a novel selective androgen receptor modulator — Piu F, Gardell LR, Son T, et al. (ACADIA Pharmaceuticals), Journal of Steroid Biochemistry and Molecular Biology (PMID 18164613), 2008. source
- 2.AC-262536 — PubChem Compound (CID 44512434) — PubChem (NIH/NLM), PubChem Compound Database, 2026. source
- 3.FDA Warns of Use of Selective Androgen Receptor Modulators (SARMs) Among Teens, Young Adults — U.S. Food and Drug Administration, FDA Consumer Update, 2023. source
- 4.Chemical Composition and Labeling of Substances Marketed as Selective Androgen Receptor Modulators and Sold via the Internet — Van Wagoner RM, Eichner A, Bhasin S, et al., JAMA 2017;318(20):2004-2010 (PMID 29183075), 2017. source
- 5.WADA Prohibited List — S1.2 Other Anabolic Agents (SARMs) — World Anti-Doping Agency, WADA Prohibited List, 2025. source
- 6.Selective Androgen Receptor Modulators (SARMs) — Prohibited Class (Anabolic Agents) — U.S. Anti-Doping Agency (USADA), USADA Spirit of Sport, 2024. source
Frequently asked questions
- What is AC-262536?
- AC-262536 is a nonsteroidal selective androgen receptor modulator (SARM) that acts as a partial agonist at the androgen receptor. It is not a peptide and is not an approved medicine anywhere — it exists only as a preclinical research chemical, characterized in a single published animal/in-vitro study (PMID 18164613, J Steroid Biochem Mol Biol 2008) from ACADIA Pharmaceuticals. In castrated rats it produced roughly 66% of testosterone's anabolic (levator ani) effect at only ~27% of its prostate (androgenic) effect, reduced plasma LH, and inhibited DHT-driven proliferation of LNCaP prostate-cancer cells in vitro. There is no human efficacy or safety data of any kind, and it is prohibited in sport by WADA (S1.2). It is not an approved medicine and has never entered published human trials.
- Is AC-262536 approved as a medicine, and where?
- No. AC-262536 is not approved for human use. The available evidence comes almost entirely from laboratory and animal studies.
- What is AC-262536 studied for?
- AC-262536 is most often discussed in the context of muscle & growth hormone. Research has examined muscle-growth-hormone. Being studied for an area does not mean it is proven or approved for it.
- Does AC-262536 have human clinical trials?
- No. The evidence for AC-262536 is almost entirely from cell and animal studies; there are no established human clinical trials.
Educational disclaimer. This article summarizes published research for informational purposes and is not medical advice. AC-262536 is a research chemical not approved for human use. Consult a qualified healthcare professional before making health decisions.