ACP-105 is an experimental nonsteroidal selective androgen receptor modulator (SARM) discovered by ACADIA Pharmaceuticals and first described in 2009. A SARM is a compound designed to activate the androgen receptor in muscle and bone while having less effect on tissues such as the prostate. ACP-105 has not been developed into an approved medicine.
The most important fact about ACP-105 is that it has only ever been studied in cells, animals and anti-doping laboratories. No human trial of its effectiveness or safety has been published or registered. It is nonetheless sold online, and anti-doping laboratories have built tests for it in human and horse samples.
This page summarizes what the discovery paper, later animal studies, anti-doping research and regulators report. It is for education only and is not medical advice.
| Property | Detail |
|---|---|
| Drug class | Nonsteroidal SARM, tropanol (8-azabicyclo[3.2.1]octane) chemical class |
| Developer | ACADIA Pharmaceuticals; first described in 2009 |
| Chemistry | C₁₆H₁₉ClN₂O, 290.8 g/mol (PubChem CID 11638442) |
| Activity at the androgen receptor | Partial agonist relative to testosterone (cell-based assays) |
| Studied doses | Animal and cell studies only; no human efficacy or safety study |
| Half-life | No human value; about 2.1 h in dogs and 2.5 h in rats after IV dosing |
| Human trials | None published; none found on ClinicalTrials.gov |
| US status | Not FDA-approved; FDA states SARMs cannot be legally marketed as dietary supplements or drugs; not named in DEA Schedule III |
| WADA status | Prohibited at all times as a SARM (class S1.2, other anabolic agents) |
What it is
ACP-105’s chemical name is 2-chloro-4-[(1R,5S)-3-hydroxy-3-methyl-8-azabicyclo[3.2.1]octan-8-yl]-3-methylbenzonitrile (PubChem). In plain terms, it is a benzene ring carrying a nitrile group, a chlorine atom and a methyl group, joined through a nitrogen atom to a tropane-like bicyclic ring that holds a hydroxyl and a methyl group. It has no steroid skeleton, so it cannot be converted by the body into estrogen or dihydrotestosterone (DHT) the way testosterone can.
ACADIA scientists found the series behind ACP-105 by high-throughput screening with a cell-based test of receptor activation called R-SAT (receptor selection and amplification technology) (Schlienger et al., J Med Chem 2009). The paper describes ACP-105 as a potent SARM with partial agonist activity relative to testosterone. A partial agonist activates the receptor but produces a smaller maximal response than a full agonist. The same chemical series also produced several androgen receptor blockers.
Anti-doping chemists group ACP-105 with ACADIA’s earlier compound AC-262536 as “tropanol” SARMs (Stacchini et al., J Pharm Biomed Anal 2021). Other SARMs in the library, such as ostarine, ligandrol and RAD-140, belong to different chemical classes, and several of them have at least some human trial data. ACP-105 does not.
Cell-based data
The discovery paper’s in vitro results are curated in the ChEMBL database (ChEMBL):
| Assay (cells, not people) | Result for ACP-105 |
|---|---|
| Normal androgen receptor, R-SAT assay: potency (EC50) | About 1 nM |
| Normal androgen receptor, R-SAT assay: maximal effect | 81% of the DHT response |
| Mutant receptor (T877A, found in some prostate cancers): maximal effect | 37% of the DHT response |
EC50 is the concentration that gives half of the compound’s maximal effect. These figures describe receptor activation in engineered cells and do not predict effects or safe exposure in humans.
How it behaves in the body
There are no published human pharmacokinetic data for ACP-105: no measured absorption, peak level or half-life in people. The only measured values come from animals and from liver cells in the laboratory, as curated from the discovery paper (ChEMBL):
| Measure | Result | Model |
|---|---|---|
| Elimination half-life after IV dosing | About 2.5 h (147.5 min) | Rats |
| Elimination half-life after IV dosing | 2.1 h | Beagle dogs |
| Oral bioavailability | 38% | Rats |
| Oral bioavailability | 56% | Beagle dogs |
| Metabolic stability half-life | 5 h | Human liver cells in culture (not a blood half-life) |
A 2025 computer-modeling study predicted a short half-life of about 1.18 h, extensive breakdown mainly by the liver enzyme CYP3A4, and entry into the brain (Fijałkowska and Jurowski, Arch Toxicol 2025). These are predictions, not measurements. A mouse study cited animal data showing that ACP-105 crosses the blood–brain barrier (George et al., ACS Chem Neurosci 2013).
About half-life figures. Websites often give ACP-105 a precise half-life in hours as if it had been measured in people. It has not. The measured values come from rats and dogs, and the computer prediction differs from the laboratory liver-cell figure.
Metabolism
Most of what is known about ACP-105’s breakdown comes from anti-doping research:
| Study | Model | Main finding |
|---|---|---|
| Thevis et al., Eur J Mass Spectrom 2014 | Rats, oral dosing | 7 major phase I metabolites (3 monohydroxylated, 4 bishydroxylated); detectable in rat urine for up to 4 and 6 days, respectively |
| Subhahar et al., Drug Test Anal 2021 | Racehorses, oral dosing | 19 metabolites in urine; ACP-105 and metabolites detected for up to 72 h |
| Broberg et al., Metabolites 2021 | Horses, oral dosing, plus human and horse liver preparations | 21 metabolites tentatively identified in blood and urine, including glucuronides |
| Broberg et al., J Chromatogr B 2023 | Human liver preparations, plus one human urine sample after a single low dose | 18 metabolites in vitro; 7 in human urine, mainly hydroxylated and glucuronide forms |
The 2023 study is the only published human exposure data. It analyzed a single post-dose urine sample to find markers for doping tests. It did not measure effects, safety or blood levels.
What the research shows
The rat study
The only published muscle data come from ACADIA’s 2-week study in castrated male rats (Schlienger et al., 2009). Castration removes the animals’ own testosterone, so any androgen-like effect can be attributed to the test compound. The paper reports that ACP-105 improved anabolic measures. ChEMBL records these results from the study (ChEMBL):
| Tissue (castrated rats, 14 days, under-skin pump) | Reversal of castration-induced loss |
|---|---|
| Levator ani muscle (a small androgen-sensitive pelvic muscle), 1 mg/kg/day | 67% |
| Prostate, 0.3–3 mg/kg/day | 21% |
In this rat model, the compound restored more of the muscle than of the prostate. This pattern is what “tissue selectivity” means for a SARM. Rat organ weights do not show whether the same selectivity, or any benefit, would occur in people.
About anabolic:androgenic ratios. Online sources often quote a precise anabolic:androgenic ratio for ACP-105. We could not find one in the primary literature, so we do not repeat one. The rat figures above come from different dose ranges and are not a ratio.
Brain and behavior studies in mice
ACP-105 was also tested as a research tool in mouse models of brain aging:
- Radiation model. In female mice given 10 Gy of radiation (7–8 mice per group), irradiated mice on vehicle performed worse on a balance task (rotorod), while irradiated mice on ACP-105 did not. ACP-105 also enhanced cued fear conditioning, a memory test (Dayger et al., Brain Res 2011).
- Alzheimer’s model. In castrated male mice engineered to develop Alzheimer-like changes, ACP-105 alone reduced anxiety-like behavior. Only the combination of ACP-105 with an estrogen receptor beta agonist (AC-186) lowered amyloid-β levels and improved spatial memory (George et al., 2013).
These are small animal studies of brain outcomes. They say nothing about muscle, performance or safety in humans.
Human evidence
None. We found no published human study of ACP-105’s effects, and searches of ClinicalTrials.gov returned no registered trials. A 2023 systematic review of SARM safety in healthy adults included 18 clinical trials and 15 case reports or case series; none involved ACP-105 (Vignali et al., J Xenobiot 2023).
Claims about muscle gain, fat loss, strength, endurance or recovery from ACP-105 in people are therefore not based on controlled evidence.
Side effects and risks
No compound-specific human safety data
Because ACP-105 has never been tested for safety in humans, its side effects, safe exposure range and interactions are unknown. Two 2025 studies used only computer models to predict ACP-105’s toxicity, including heart-rhythm (hERG) effects and mutagenicity (Fijałkowska and Jurowski, Arch Toxicol 2025), and its handling by the body (Fijałkowska and Jurowski, 2025). Such predictions can point to questions for laboratory testing, but they are not evidence of safety or harm in people.
As an androgen receptor agonist, ACP-105 would be expected to act on the hormone feedback loop that controls natural testosterone production, as other androgens do. How strongly it does this in people has never been measured.
Class-level risks
FDA warns that SARMs are not FDA-approved and that studies and reports link them to serious or life-threatening problems (FDA, 2023), including:
- increased risk of heart attack or stroke;
- liver injury and acute liver failure;
- psychosis or hallucinations, and sleep disturbances;
- sexual dysfunction, infertility and testicular shrinkage;
- miscarriage.
Published case data center on the liver:
| Source | What it found (SARMs as a class) |
|---|---|
| Vignali et al., 2023, systematic review, 33 studies | 15 reported cases of drug-induced liver injury, 1 Achilles tendon rupture, 1 rhabdomyolysis; ALT (a liver enzyme) elevation in a mean 7.1% of SARM-exposed trial participants |
| Leciejewska et al., Eur J Clin Pharmacol 2024, review of reported cases | 20 published adverse-event reports since 2020, mostly cholestatic or hepatocellular liver injury with jaundice |
These findings involve other SARMs, not ACP-105 specifically, and cannot be assumed to apply equally to every compound.
Quality and contamination
ACP-105 is not made under pharmaceutical quality control. In a JAMA analysis of 44 products sold online as SARMs (Van Wagoner et al., JAMA 2017):
| Finding | Products |
|---|---|
| Contained 1 or more SARMs | 23 of 44 (52%) |
| Contained another unapproved drug instead or as well | 17 of 44 (39%) |
| Contained substances not listed on the label | 11 of 44 (25%) |
| Contained no active compound | 4 of 44 (9%) |
| Amount matched the label | 18 of 44 (41%) |
The SARMs detected were ostarine, LGD-4033 and andarine. A buyer therefore cannot be sure what a product labeled as ACP-105 actually contains, or how much.
Legal status and anti-doping
- United States. ACP-105 is not an approved drug. FDA states that SARMs “cannot be legally marketed in the U.S. as a dietary supplement or drug” (FDA, 2023). It is not named among the anabolic steroids in DEA Schedule III (21 CFR 1308.13).
- Sport. SARMs have been on the WADA Prohibited List since 2008 (Thevis and Schänzer, Mol Cell Endocrinol 2018). The 2026 list prohibits SARMs at all times, in and out of competition, under S1.2 “Other anabolic agents,” as non-specified substances (WADA 2026 Prohibited List). The list’s examples are not exhaustive, so ACP-105 is covered even though it is not named.
Laboratories have built tests that include ACP-105:
| Matrix | Context | Source |
|---|---|---|
| Reference material | Fragmentation data to add ACP-105 to sports drug testing methods | Thevis et al., Rapid Commun Mass Spectrom 2013 |
| Human urine | Validated multi-SARM method; detection capability 0.1–1.0 ng/mL across the screened compounds | Stacchini et al., 2021 |
| Human urine | Two monohydroxylated metabolites proposed as test targets | Broberg et al., 2023 |
| Human hair | Validated screen of 9 SARMs and 2 metabolic modulators | Gheddar et al., J Chromatogr B 2021 |
| Horse urine and plasma | Metabolite targets for equine doping control | Broberg et al., 2021; Subhahar et al., 2021 |
Key takeaways
- An abandoned research compound. ACP-105 is a nonsteroidal SARM from ACADIA Pharmaceuticals, described in 2009 and never approved as a medicine.
- Preclinical data only. It is a partial androgen receptor agonist in cells, and in castrated rats it restored more pelvic muscle than prostate weight over 2 weeks.
- No human trials. There are no published human data on effectiveness, safety or blood levels, and no registered trials. The only human data are a metabolite analysis for doping tests.
- Half-life claims are not human data. Measured half-lives of about 2–2.5 h come from rats and dogs.
- Class risks and unreliable products. FDA links SARMs to liver injury and other serious harms, and products sold as SARMs are often mislabeled.
- Prohibited in sport. WADA bans all SARMs at all times, and anti-doping methods already detect ACP-105 and its metabolites.
Sources
- Schlienger N, Lund BW, Pawlas J, et al. Synthesis, structure-activity relationships, and characterization of novel nonsteroidal and selective androgen receptor modulators. J Med Chem. 2009;52(22):7186–7191. PubMed.
- European Bioinformatics Institute. ACP-105, ChEMBL compound CHEMBL3084681 (bioactivity data curated from Schlienger et al. 2009, ChEMBL document CHEMBL1156129). ChEMBL.
- National Center for Biotechnology Information. ACP-105, PubChem CID 11638442. PubChem.
- Stacchini C, Botrè F, Comunità F, et al. Simultaneous detection of different chemical classes of selective androgen receptor modulators in urine by liquid chromatography-mass spectrometry-based techniques. J Pharm Biomed Anal. 2021;195:113849. PubMed.
- Fijałkowska O, Jurowski K. First multifaceted ADME profile of ACP-105 (CAS: 1048998-11-3): a novel non-steroidal selective androgen receptor modulator used as doping in sports-integrative in silico toxicological studies for clinical and forensic toxicology purposes. Arch Toxicol. 2025;99(12):5047–5063. PubMed.
- Fijałkowska O, Jurowski K. Toxicity of ACP-105: a substance used as doping in sports: application of in silico methods for prediction of selected toxicological endpoints. Arch Toxicol. 2025;99(4):1485–1503. PubMed.
- George S, Petit GH, Gouras GK, et al. Nonsteroidal selective androgen receptor modulators and selective estrogen receptor β agonists moderate cognitive deficits and amyloid-β levels in a mouse model of Alzheimer’s disease. ACS Chem Neurosci. 2013;4(12):1537–1548. PubMed.
- Dayger C, Villasana L, Pfankuch T, et al. Effects of the SARM ACP-105 on rotorod performance and cued fear conditioning in sham-irradiated and irradiated female mice. Brain Res. 2011;1381:134–140. PubMed.
- Thevis M, Thomas A, Piper T, et al. Liquid chromatography-high resolution/high accuracy (tandem) mass spectrometry-based identification of in vivo generated metabolites of the selective androgen receptor modulator ACP-105 for doping control purposes. Eur J Mass Spectrom (Chichester). 2014;20(1):73–83. PubMed.
- Subhahar MB, Karakka Kal AK, Philip M, et al. Detection and identification of ACP-105 and its metabolites in equine urine using LC/MS/MS after oral administration. Drug Test Anal. 2021;13(2):299–317. PubMed.
- Broberg MN, Knych H, Bondesson U, et al. Investigation of equine in vivo and in vitro derived metabolites of the selective androgen receptor modulator (SARM) ACP-105 for improved doping control. Metabolites. 2021;11(2):85. PubMed.
- Broberg MN, Ohlsson RT, Bondesson U, et al. A multivariate data analysis approach for the investigation of in vitro derived metabolites of ACP-105 in comparison with human in vivo metabolites. J Chromatogr B Analyt Technol Biomed Life Sci. 2023;1231:123927. PubMed.
- Thevis M, Piper T, Beuck S, et al. Expanding sports drug testing assays: mass spectrometric characterization of the selective androgen receptor modulator drug candidates RAD140 and ACP-105. Rapid Commun Mass Spectrom. 2013;27(11):1173–1182. PubMed.
- Gheddar L, Raul JS, Kintz P. Development and validation of SARMs and metabolic modulators screening in hair using UHPLC-MS/MS: application to a doping case and first identification of S23 in authentic human hair. J Chromatogr B Analyt Technol Biomed Life Sci. 2021;1187:123048. PubMed.
- Vignali JD, Pak KC, Beverley HR, et al. Systematic review of safety of selective androgen receptor modulators in healthy adults: implications for recreational users. J Xenobiot. 2023;13(2):218–236. PubMed.
- Leciejewska N, Jędrejko K, Gómez-Renaud VM, et al. Selective androgen receptor modulator use and related adverse events including drug-induced liver injury: analysis of suspected cases. Eur J Clin Pharmacol. 2024;80(2):185–202. PubMed.
- Van Wagoner RM, Eichner A, Bhasin S, Deuster PA, Eichner D. Chemical composition and labeling of substances marketed as selective androgen receptor modulators and sold via the internet. JAMA. 2017;318(20):2004–2010. PubMed.
- Thevis M, Schänzer W. Detection of SARMs in doping control analysis. Mol Cell Endocrinol. 2018;464:34–45. PubMed.
- US Food and Drug Administration. FDA warns of use of selective androgen receptor modulators (SARMs) among teens, young adults. Consumer update, content current as of April 26, 2023. FDA.
- Drug Enforcement Administration. Schedules of controlled substances: Schedule III. 21 CFR 1308.13. eCFR.
- World Anti-Doping Agency. The 2026 Prohibited List, in effect from January 1, 2026. WADA 2026 Prohibited List.
- US National Library of Medicine. ClinicalTrials.gov search for “ACP-105.” ClinicalTrials.gov.