PF-06260414
PF-06260414 is a non-steroidal selective androgen receptor modulator developed by Pfizer that reached a single-dose Phase 1 study in healthy men. It is one of the few SARMs with any published human pharmacokinetic and safety data, though characterisation remains early and limited to short exposure.
01 Overview
PF-06260414 was designed as an orally active SARM with the usual goal of muscle and bone anabolism sparing the prostate. Preclinical work supported tissue selectivity, and it advanced to a first-in-human single-ascending-dose study.
That Phase 1 evaluation in healthy men characterised its pharmacokinetics and short-term tolerability and reported effects on sex-hormone-binding globulin and other biomarkers consistent with androgenic activity. Development did not continue to efficacy trials, so long-term human data are absent, but it stands out for having any peer-reviewed clinical exposure at all.
02 Mechanism
A non-steroidal selective androgen receptor modulator that binds and activates the androgen receptor with relative anabolic selectivity for muscle and bone.
03 Dosing
| Tier | Dose | Route | Notes |
|---|---|---|---|
| Phase 1 single-dose | 3–100 mg | Oral | Single-ascending-dose range studied in healthy men; no repeat-dose regimen established. |
Ester comparison
| Ester | Half-life | Injection freq. | Testosterone by mass |
|---|
04 Effects
| Effect | Magnitude | Evidence | |
|---|---|---|---|
| Androgenic biomarker changesSingle dosing altered sex-hormone-binding globulin and related biomarkers, confirming androgen activity. | SHBG and hormone shifts | Clinical | |
| Anabolic potentialMuscle/bone anabolic effects shown in animal models; not tested for efficacy in humans. | Preclinical | Preclinical |
05 Side effects
| Effect | Severity | Frequency | Evidence | Countermeasures |
|---|---|---|---|---|
| HPTA / hormone suppressionAs an androgen agonist it is expected to suppress endogenous hormones with repeated use, though only single-dose human data exist. | Moderate | Unknown | Preclinical | |
| Unknown repeat-dose safetyOnly single-dose human exposure has been reported; chronic safety is uncharacterised. | Moderate | Unknown | Unconfirmed |