MK-4541
MK-4541 is an experimental compound from Merck characterised as a selective androgen receptor modulator with additional 5-alpha-reductase inhibitory activity, intended to give muscle-anabolic effects while limiting prostate stimulation. It is preclinical, with no human efficacy or safety data.
01 Overview
MK-4541 was studied as a dual-acting molecule: a SARM that also inhibits 5-alpha-reductase, aiming to build muscle while actively suppressing dihydrotestosterone-driven prostate growth. In animal models it increased muscle mass and reduced fat while limiting prostate effects.
MK-4541 has not advanced to published human trials and is not approved. It appears rarely in the grey market. Its unusual dual mechanism makes cross-extrapolation from other SARMs unreliable, and no human dosing has been validated.
02 Mechanism
Selective androgen receptor modulator that also inhibits 5-alpha-reductase, promoting muscle anabolism while blocking conversion of testosterone to dihydrotestosterone to limit prostate stimulation.
03 Dosing
| Tier | Dose | Route | Notes |
|---|---|---|---|
| Anecdotal | 10–25 mg/day | Oral | No validated human dose; speculative. |
Ester comparison
| Ester | Half-life | Injection freq. | Testosterone by mass |
|---|
04 Effects
| Effect | Magnitude | Evidence | |
|---|---|---|---|
| Increased muscle massAnabolic effect on skeletal muscle in rodent models. | Preclinical | ||
| Reduced fat massDecreased adiposity observed in animal studies. | Preclinical | ||
| Prostate protection5-alpha-reductase inhibition limited prostate growth in models. | Preclinical |
05 Side effects
| Effect | Severity | Frequency | Evidence | Countermeasures |
|---|---|---|---|---|
| HPTA suppressionAndrogen receptor agonism is expected to suppress endogenous testosterone. | Moderate | Expected | Preclinical | |
| Sexual/libido effects5-alpha-reductase inhibition may reduce DHT and affect libido, as seen with finasteride-class drugs; unstudied here. | Moderate | Uncharacterised | Unconfirmed |