ACP-105

Chemical identity

ACP-105 emerged from a medicinal-chemistry programme at Acadia Pharmaceuticals exploring non-steroidal androgen receptor ligands built on a bicyclic hydantoin-adjacent core. It is structurally unrelated to the aryl-propionamide compounds — ostarine, andarine — that dominate the older SARM literature.

The compound is a partial agonist rather than a full one. That distinction is the whole point of its design: a partial agonist produces a submaximal response even at receptor saturation, and in a tissue where endogenous androgen already occupies the receptor it can behave as a functional antagonist.

Mechanism in research models

Like all SARMs, ACP-105 binds the androgen receptor ligand-binding domain and drives nuclear translocation and androgen-response-element transcription. Tissue selectivity arises downstream, from which co-regulator proteins the resulting receptor conformation recruits.

Published rodent work reports anabolic activity in levator ani muscle at doses producing considerably less prostate response than testosterone propionate — the standard dissociation assay in this field. The reported ratio is the compound's main claim to interest.

As a partial agonist, ACP-105 shows a ceiling effect. Dose-response work should be designed to find that plateau rather than assuming monotonic behaviour across the range, and results at high concentration will not extrapolate from low-concentration data.

What the literature establishes

The preclinical dataset is small. A handful of rodent studies covering muscle and bone endpoints, plus receptor pharmacology characterising the partial-agonist profile, constitute most of what exists. There is no published human clinical data.

Some work has examined cognitive and neuroprotective endpoints in rodent models, reflecting androgen receptor expression in the central nervous system. These findings are preliminary and single-source.

ACP-105 is prohibited in sport at all times under WADA's S1.2 classification. It is detectable in standard anti-doping screens and has appeared in adverse analytical findings, so investigators should treat contamination control seriously in shared laboratory spaces.

Handling, storage and solubility

Non-steroidal SARMs of this class are typically held sealed at −20 °C, protected from light and moisture, and are stable as dry solids over extended periods under those conditions. The physical form and the validated storage condition for your material are the ones stated on its lot documentation.

Practically insoluble in water. Prepare stock solutions in DMSO, then dilute into aqueous buffer immediately before use. Keep final DMSO concentration below 0.1% in cell culture and include a vehicle-only control at matched concentration — DMSO alone affects many cellular endpoints.

DMSO stocks are hygroscopic and take up atmospheric water on repeated opening, which changes the effective concentration. Aliquot stocks on preparation and thaw each aliquot once.

Analytical documentation

Expect HPLC or UPLC purity, a proton NMR spectrum and mass confirmation. For small molecules, NMR is the identity check that matters — it distinguishes structural isomers that share a molecular formula and would be indistinguishable by mass alone.

Given the limited published characterisation of this compound, request the full analytical package rather than a purity number in isolation, and retain the certificate with your experimental records.

References and authoritative sources

Chemical identity, regulatory status and anti-doping classification should be confirmed against primary sources rather than against this page. The records below are the ones to check first.

1. PubChem compound record (US National Library of Medicine)
2. PubMed indexed literature

These are database and regulatory sources. Citations to specific primary papers are being added to this page as part of ongoing scientific review; until they appear, treat the mechanism and literature sections above as a summary to verify rather than a citation of record.