ACP-105
Also known as: ACP-105, ACP105
A mild SARM originally developed for cognitive and bone endpoints in the elderly — low doses, modest effect, and the same absence of human data as the rest of the second tier.
Substance family
Non-steroidal compounds binding the same androgen receptor as testosterone, but favouring muscle and bone over prostate and hair. The selectivity is real; the suppression of the body's own production is not avoided by it. None is approved anywhere.
Effects on
Which outcomes this substance acts on — descriptive, not a recommendation.
Strain profile
Where this substance is most likely to hit — a rough orientation, individually dependent on dose, duration and predisposition.
This substance causes
Dosing & protocols by goal
Rough orientation ranges as reported in harm-reduction literature — not an individual treatment plan. Doses are individual and open-ended; frequency depends on the ester or half-life.
Human clinical data
MedicalDose
Does not exist
Frequency
—
Cycle length
—
Developed by a Swedish research programme for bone and cognitive endpoints in ageing. Animal work only; no human trial was conducted.
Grey market practice
Not a recommendationDose
3–8 mg / day reported
Frequency
Split into 2 doses
Cycle length
6–8 weeks reported
The doses are lower than most SARMsSARMsA non-steroidal compound that binds the androgen receptor with claimed tissue selectivity. because it is potent per milligram, not because it is gentler. Figures come from user reports without research backing.
Side effect & countermeasure
Typical problems and what you can do to reduce harm — at a glance. Does not replace medical monitoring.
Problem
Low milligram doses are mistaken for low risk
Countermeasure
ACP-105 is dosed at single-digit milligrams while ostarine runs at 10–25 mg. That reflects potency per milligram, not mildness. Comparing SARMsSARMsA non-steroidal compound that binds the androgen receptor with claimed tissue selectivity. by dose number rather than by effect is one of the more common errors in this category.
Problem
Suppression
Problem
Falling HDL
Countermeasure
As with the other oral SARMsSARMsA non-steroidal compound that binds the androgen receptor with claimed tissue selectivity.. Cardio, omega-3 and citrus bergamot soften it; a lipid panel decides whether to continue.
Problem
The cognitive claims are not human findings
Countermeasure
ACP-105 was studied for cognitive endpoints in ageing animals, which is where the nootropic framing comes from. Rodent behavioural results are not a statement about human cognition, and nothing has been measured in a person.
Problem
No manufacturing oversight
Countermeasure
Sold as a research chemical. Analyses of grey market SARMsSARMsA non-steroidal compound that binds the androgen receptor with claimed tissue selectivity. repeatedly find wrong compounds, wrong doses or nothing at all. Third-party testing is a partial answer, not a guarantee.
Overview
ACP-105 is a second-tier SARM: a genuine research compound with a defined development history that never reached human testing, now sold because the well-known names attract more scrutiny.
It came out of a Swedish research programme aimed at age-related decline — bone density and cognitive function in particular, rather than athletic performance.
Mechanism of Action
A non-steroidal partial agonist at the androgen receptor with preferential activity in muscle and bone. In animal studies it increased lean mass and bone density with less prostate stimulation than testosterone, which is the standard SARM profile.
The distinctive part of the research was the interest in cognition. Androgen receptors are present in brain regions involved in memory, and the programme investigated whether selective activation there might help with age-related decline. Those were animal behavioural studies.
Half-life is around five to seven hours, hence split dosing.
Reading the Dose Correctly
ACP-105 is used at three to eight milligrams a day, against ten to twenty-five for ostarine. That difference regularly gets read as evidence that it is gentler.
It is not. It means more effect per milligram. Judging a compound's harshness by the number on the label is meaningless across different molecules — what matters is the effect at the dose actually used, and at typical doses ACP-105 suppresses the axis and lowers HDL like the others.
Honest Placement
Among SARMs it sits at the milder end, closer to ostarine than to S-23 in reported effect and suppression. The muscle gains described are modest.
What it shares with the rest of the second tier is the fundamental problem: preclinical only. There is no human safety data, no known dose-response in people, and no idea what repeated cycles do. A milder compound with no human data is still a compound with no human data.
Side Effects & Risks
- Suppression of the body's own production
- Falling HDL, rising LDL
- Mildly elevated liver values reported
- Fatigue and low mood, largely downstream of suppression
- No manufacturing oversight; contamination and mislabelling are common
Blood Work & Monitoring
- Total and free testosterone, LH, FSH — before, during and after
- Lipid profile (LDL, HDL, triglycerides)
- Liver values (ALT, AST, GGT)
- Estradiol (sensitive assay) — falls with suppressed testosterone
Legal status by region
Regulation differs considerably between jurisdictions and changes over time. This is a rough orientation, not legal advice — check the rules that apply where you are.
| Region | Regulatory status |
|---|---|
| United States | Not approved; FDA warning issued |
| EU / UK | No marketing authorisationNeither a medicine nor a supplement — no legal route for human use. |
| Most other jurisdictions | Unregulated grey area |
| Competitive sport | Prohibited at all timesListed by WADA under S1.2. |