ACP-105 Dosage: What the Evidence Actually Shows

Key takeaways

What Is ACP-105?

ACP-105 is a nonsteroidal selective androgen receptor modulator (SARM) originally developed by ACADIA Pharmaceuticals as part of an internal SARM discovery program that produced compounds ranging from full and partial agonists to full antagonists of the androgen receptor. The first pharmacological characterization, presented by Bradley and colleagues at the Experimental Biology 2008 meeting and later published as a conference abstract, reported that ACP-105 behaves as a partial androgen receptor agonist, partially reversing the androgenic effect of exogenous testosterone.

Selleck Chemicals, a laboratory chemical supplier, lists ACP-105 as an orally available, potent SARM with high potency at both the wild-type androgen receptor and a mutant form associated with prostate cancer research, T877A. The same ACADIA characterization work found that ACP-105 had minimal trophic effects on the prostate in castrated animals and no detectable trophic effect on the prostate in intact rats, the tissue-selectivity signature that defines the SARM class, while producing robust anabolic effects on muscle in castrated rat models.

ACP-105 has also been studied in rodent models of cognitive function, including a study in irradiated female mice and a separate study examining nonsteroidal androgen receptor and estrogen receptor beta agonists in a mouse model of Alzheimer's disease. These studies used the compound as a pharmacological tool to probe androgen receptor signaling in the brain; they do not establish a therapeutic role, a safe human dose, or effectiveness in humans.

Despite this preclinical interest, ACP-105 was never advanced into registered human clinical trials. It is currently sold only as an unregulated research chemical, and a 2025 toxicological analysis notes that it is increasingly detected in anti-doping analyses even though it still lacks a comprehensive human pharmacokinetic profile.

Is There an Official or Medically Approved ACP-105 Dosage?

No. ACP-105 is not an FDA-approved drug, and there is no dosage established through human clinical trials. Chemical suppliers that label the product "for research use only" and state that they "do not sell to patients" are describing its actual regulatory status accurately, even when other sellers market dosed capsules or liquids toward bodybuilders under similar research-only disclaimers.

Because no controlled human pharmacokinetic or dose-ranging studies of ACP-105 have been published, any specific milligram figure presented online as a human "dosage" is not derived from clinical evidence. It is either a mathematical extrapolation from rodent efficacy studies, a figure copied from vendor product pages that market the compound directly for bodybuilding despite research-only labeling, or an anecdotal report from unsupervised users of an unregulated substance.

The FDA has taken enforcement action against companies selling SARM products labeled as research chemicals while marketing them for human use, finding that such labeling does not change the fact that the products are unapproved drugs intended for use in humans. This is consistent with the FDA's broader statement that products containing SARMs are unapproved drugs that have not been reviewed by the agency for safety or effectiveness, regardless of how they are labeled.

What the Animal Dosing Data Actually Shows

The dosing figure most often cited online, 1 mg/kg per day, originates from specific rodent studies. In one published study, mice were implanted with minipumps delivering ACP-105 at 1 mg/kg/day to examine its effects on rotorod performance and fear conditioning after irradiation. A related product summary from Cayman Chemical notes that at this same dose, ACP-105 inhibited radiation-induced decreases in a memory-related behavioral measure in female mice. This illustrates that the 1 mg/kg/day figure comes from a narrow experimental context involving irradiated mice, not from a general muscle-building or efficacious human dose.

The original ACADIA characterization work, conducted in castrated rats, reported that ACP-105 had anabolic effects on the levator ani muscle comparable to testosterone while sparing the prostate, and the researchers proposed on this basis that ACP-105 might be a superior therapeutic alternative to testosterone. These findings come from short-duration animal experiments in specific rat and mouse models, not from dose-ranging safety studies designed to define a tolerable or effective range in a living human body.

A 2025 in silico ADME (absorption, distribution, metabolism, excretion) analysis assembled seven independent computational models, including ADMETlab 3.0, SwissADME, and pkCSM, to characterize ACP-105 because, as the authors note, it is increasingly detected in anti-doping analyses yet lacking a comprehensive ADME profile. The models predicted high gastrointestinal absorption, moderate lipophilicity, and low aqueous solubility. These are theoretical, model-derived estimates rather than measurements from human dosing studies, and the authors' own framing underscores that ACP-105 still lacks verified human pharmacokinetic data.

Why "Human Equivalent Dose" Conversions Are Unreliable

Online bodybuilding and SARM-vendor sources commonly take the 1 mg/kg/day rodent dose and scale it by an assumed human body weight, and separately, some vendor product pages list suggested doses in the range of roughly 10 to 20 mg per day alongside anecdotal cycle lengths. Neither figure is a validated human dose. The rodent-to-human scaling method, sometimes labeled a "human equivalent dose," is a crude linear conversion that does not account for interspecies differences in metabolism, receptor density, oral bioavailability, or elimination half-life.

Formal human-equivalent-dose methodology used in real drug development, typically based on body surface area rather than simple weight scaling, is intended only to select a safe starting dose for a first-in-human trial conducted under medical supervision with escalating cohorts and predefined safety stopping rules. It was never intended, and is not validated, as a method for unsupervised consumers to self-administer an unapproved investigational compound purchased online.

Because ACP-105 never reached first-in-human trial stage, there is no published safety margin, no maximum tolerated dose in people, and no data on how the rodent-derived anabolic effect relates to any specific milligram amount in a human being. Any number presented with confidence as a "safe" or "effective" human dose for ACP-105 is not supported by the primary literature.

Legal Status and Anti-Doping Status

ACP-105 is not approved for human use in any country. The FDA has warned that body-building products containing SARMs generally have not been approved by the agency and are associated with serious safety concerns, including the potential for increased risk of heart attack or stroke and life-threatening reactions such as liver toxicity. Regulators state plainly that these products, even when labeled as dietary supplements or as "research-grade" compounds, are unapproved drugs that have not been reviewed by the FDA for safety and effectiveness.

SARMs as a class are classified by the World Anti-Doping Agency under the "Other Anabolic Agents" category of the Prohibited List, a classification a 2025 toxicological analysis notes has been in place since 2008, and prohibited substances in this category are banned at all times, both in and out of competition, for any tested athlete.

ACP-105 specifically has been the subject of equine anti-doping metabolite research. A 2021 study identified in vitro metabolites of ACP-105 and several other nonsteroidal SARMs using equine liver preparations, work conducted for doping-control purposes in horse racing rather than to establish therapeutic dosing in any species.

Reported Risks, Quality Concerns, and Why Self-Dosing Is Especially Risky

Independent laboratory analyses have repeatedly found that SARM products sold online do not reliably contain what their labels claim. A JAMA-published chemical composition study purchased 44 products marketed online as SARMs and found that only 23, or 52 percent, actually contained one or more of the SARMs named on the label, while many others contained undeclared unapproved drugs. This general problem in the SARM market means a person attempting to follow any "dosage" listed on a bottle, including one labeled ACP-105, cannot be confident of the actual amount, purity, or even identity of what they are taking, since ACP-105 itself has not been independently verified as a common constituent in these product surveys.

Case reports describe drug-induced liver injury attributed to SARM use generally, most often involving compounds such as RAD-140 and ostarine that have seen wider recreational use than ACP-105. One published case involved a 29-year-old bodybuilder who presented with painless jaundice, pruritus, fatigue, and significantly elevated liver function tests after using SARM supplements, illustrating that hepatotoxicity from this drug class is not purely theoretical.

A LiverTox review compiled by the National Institutes of Health notes that multiple reports of clinically apparent liver injury with jaundice have occurred in people taking SARMs for bodybuilding on their own and without medical supervision, with a typical latency of two to three months, and that there are no known effective therapies for this liver injury beyond stopping the offending product. No case report specific to ACP-105 was identified in the literature reviewed for this page.

Because ACP-105 has no human trial safety data at any dose, none of the general SARM-class risk information above can be quantified specifically for ACP-105. The honest evidentiary conclusion is that its human risk profile at any dose is unknown, not merely "lower risk" because it behaved as a partial rather than full agonist in animal assays.

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