Androgen Receptor Modulators (SARMs)
PF-06260414
PF-06260414; PF 06260414; PF06260414; 6-[(4R)-4-methyl-1,1-dioxo-1,2,6-thiadiazinan-2-yl]isoquinoline-1-carbonitrile
9 min read · Updated July 10, 2026 · 7 references
Curated by PeptideInfo Wikilast reviewed how we verify
PF-06260414 is a synthetic nonsteroidal SARM developed by Pfizer — not a peptide and not a steroid. Its only human data come from one completed Phase 1 first-in-human study in healthy men (single doses 1–400 mg and multiple doses 3–100 mg twice daily; NCT02070939). It was generally well tolerated with no serious adverse events, but elevated ALT (a liver enzyme) was the most frequent adverse event, and it dose-dependently suppressed total testosterone, SHBG, and HDL cholesterol — a signature consistent with on-target androgen activity and testosterone (HPTA) suppression. There is no public evidence it advanced beyond Phase 1. It is not approved for any use and is WADA-prohibited at all times.
Evidence: In human clinical trials; not yet approved.
- Nonsteroidal selective androgen receptor modulator (SARM) — NOT a peptide, NOT a steroid
- Developed by Pfizer; a thiadiazinane-isoquinoline-carbonitrile small molecule (C14H14N4O2S, CAS 1612755-71-1, PubChem CID 76071881)
- Only human data is a single completed Phase 1 first-in-human study in healthy men (NCT02070939; PMID 27085586) — no public development beyond Phase 1
- Generally well tolerated with no serious adverse events in the short study, but elevated ALT (a liver enzyme) was the most frequent adverse event
- Dose-dependently suppressed total testosterone, SHBG, and HDL cholesterol — on-target androgenic activity implying HPTA (testosterone) suppression and an unfavorable lipid effect
- Not approved for any use; WADA-prohibited at all times under S1.2 (Other Anabolic Agents)
A nonsteroidal selective androgen receptor modulator (SARM) — a small synthetic molecule (thiadiazinane-substituted isoquinoline-carbonitrile, C14H14N4O2S, CAS 1612755-71-1, PubChem CID 76071881), NOT a peptide — developed by Pfizer. It reached a single completed Phase 1 first-in-human study in healthy men (NCT02070939; Bhattacharya et al., Clin Ther 2016, PMID 27085586) and shows no public development beyond Phase 1. It is NOT an approved medicine for any use, including muscle growth, physique, or performance.
Overview
PF-06260414 (also written PF 06260414 or PF06260414) is a nonsteroidal selective androgen receptor modulator (SARM) — a small synthetic molecule built on a thiadiazinane-substituted isoquinoline-carbonitrile scaffold (C14H14N4O2S). It is NOT a peptide and NOT a steroid — it is a designed small-molecule drug intended to activate the androgen receptor in a tissue-selective way.
PF-06260414 was developed by Pfizer. Its entire public human record is a single completed Phase 1 first-in-human study in healthy adult men (NCT02070939; Bhattacharya et al., Clinical Therapeutics 2016, PMID 27085586). There is no public evidence that it advanced beyond Phase 1, and its intended clinical indication was never publicly finalized. It appears on this peptide reference because it is discussed, sold, and stacked alongside peptides in the "research chemical" community — not because it is one.
Not approved — investigational, with androgen-suppression and a liver-enzyme signal
PF-06260414 is not approved by any regulator (FDA, EMA, or otherwise) for any use, including muscle growth, physique, or performance. Its only human exposure is a single, short Phase 1 study. In that study it was generally well tolerated with no serious adverse events, but elevated ALT (a liver enzyme) was the most frequent adverse event, and it dose-dependently suppressed total testosterone, SHBG, and HDL cholesterol — a signature consistent with on-target androgen activity that also implies HPTA (natural testosterone) suppression. No long-term human safety data exist. As a SARM it is WADA-prohibited at all times. This page is educational and is not medical, legal, or dosing advice; nothing here endorses or guides human use. This is not a "milder, safer, or legal alternative" to anabolic steroids. Dated 2026-07-10.
Chemistry and structure
PF-06260414 is a small-molecule isoquinoline-carbonitrile bearing a cyclic sulfamide (thiadiazinane 1,1-dioxide) — an amino-acid chain it is not.
| Property | Value |
|---|---|
| Name | PF-06260414 (6-[(4R)-4-methyl-1,1-dioxo-1,2,6-thiadiazinan-2-yl]isoquinoline-1-carbonitrile) |
| Class | Nonsteroidal selective androgen receptor modulator (SARM) — not a peptide, not a steroid |
| Molecular formula | C14H14N4O2S |
| Molecular weight | 302.35 g/mol (PubChem CID 76071881) |
| CAS number | 1612755-71-1 |
| Developer | Pfizer |
| Route | Orally active |
| Elimination half-life | ~6.9–12.8 h (oral, healthy adult men; PMID 27085586) |
Mechanism of action
- Androgen receptor (AR) modulation [Human]. PF-06260414 acts as a nonsteroidal SARM: it binds the androgen receptor and exerts tissue-selective agonist activity, favoring anabolic (muscle) over androgenic effects. This class mechanism was confirmed in the Phase 1 study by dose-dependent modulation of androgen-sensitive biomarkers (SHBG, total testosterone, HDL) in healthy men (PMID 27085586).
- Tissue-selective design [In vitro]. The compound was deliberately selected to perform well in a muscle (anabolic) assay while minimizing effect in an androgenic-response assay. Its pharmacophore is an isoquinoline-carbonitrile with a cyclic sulfamide (thiadiazinane 1,1-dioxide); the medicinal-chemistry strategy aimed at tissue-selective AR activity. This is a design rationale, not a demonstrated clinical safety margin.
- Testosterone (HPTA) suppression [Human]. The dose-dependent suppression of total testosterone indicates on-target androgenic feedback on the hypothalamic-pituitary- testicular axis (HPTA suppression). Maximal biomarker effects were seen at the highest multiple-dose level (100 mg twice daily) (PMID 27085586).
Research and evidence
The entire human evidence base is one completed Phase 1 study. There is no efficacy trial — no human study of lean mass, physical function, or any physique/performance endpoint exists. The Phase 1 study measured safety, pharmacokinetics, and pharmacodynamics (biomarkers) in healthy volunteers only.
| Finding | Model | Source |
|---|---|---|
| Single completed Phase 1 first-in-human study: randomized, double-blind, SAD (1–400 mg) and MAD (3–100 mg BID, plus 60 mg once daily and a Japanese 30 mg BID cohort) in healthy adult men | [Human] — Phase 1 (completed) | Bhattacharya I et al., Clin Ther 2016 (PMID 27085586); NCT02070939 |
| Pharmacokinetics: rapid absorption (median Tmax ~1–2 h), half-life ~6.9–12.8 h; Japanese subjects showed markedly higher exposure (Cmax +98.6%, AUCτ +79.5% vs Western subjects) | [Human] — Phase 1 | PMID 27085586 |
| Pharmacodynamics: dose-dependent decreases in total testosterone, SHBG, and HDL cholesterol; greatest at 100 mg BID | [Human] — Phase 1 | PMID 27085586 |
| No public evidence of any Phase 2 or later development; the compound did not advance beyond Phase 1 in the public record | [Human] — none beyond Phase 1 | ClinicalTrials.gov / literature search (no later trials found) |
Human evidence in context. The only controlled human data are safety, PK, and PD in healthy men — not efficacy. Whether PF-06260414 builds muscle or improves physical function in humans is not established; no efficacy trial exists. The higher exposure in Japanese subjects is real but its metabolic/pharmacogenomic basis is not established.
Status and regulation
- Regulatory approval: None. PF-06260414 is not approved by the FDA, the EMA, or any other regulator for any indication. It is investigational — a single Phase 1 study completed, with no public development beyond Phase 1. Its status is effectively discontinued/inactive in the public record, but not officially confirmed as terminated. The intended clinical indication (muscle-wasting/cachexia is the typical SARM target) was never publicly finalized for this compound.
- Anti-doping: Prohibited by the World Anti-Doping Agency (WADA) at all times (in- and out-of-competition) as a SARM, under S1.2 (Other Anabolic Agents). WADA is a sport-eligibility axis and is separate from any question of legality.
- Market reality: Outside of that single trial, any material sold under this name is an unregulated "research chemical" of unknown identity, purity, and potency.
Safety
Androgen suppression and a liver-enzyme signal — with no long-term human data
In the only human study, PF-06260414 was generally well tolerated with no serious adverse events, but the picture is short and limited. Elevated ALT (a liver enzyme) was the most frequent adverse event (7 subjects), and headache was also reported (3 subjects) [Human]. It dose-dependently suppressed total testosterone — indicating HPTA (natural testosterone) suppression, an expected on-target risk for SARMs [Human] — and dose-dependently lowered HDL cholesterol, an unfavorable lipid effect typical of androgenic agents [Human]. No long-term human safety data exist: the only human exposure is a short single Phase 1 study, so chronic effects, carcinogenicity, fertility, and cardiovascular outcomes are unstudied for this specific compound [Hypothesis].
Documented and expected safety signals (tagged by evidence type):
- Elevated ALT / liver-enzyme signal [Human]. Elevated ALT was the most frequent adverse event in the Phase 1 trial (7 subjects); headache was reported in 3 subjects. No serious adverse events occurred in this short study. Whether the ALT elevations reflected clinically significant liver injury or transient enzyme changes is not established beyond the short trial.
- Testosterone / HPTA suppression [Human]. Dose-dependent suppression of total testosterone indicates suppression of the hypothalamic-pituitary-testicular axis; androgen-suppressive endocrine effects are expected on-target risks for SARMs. No dosing, "cycle," or post-cycle guidance is given here.
- Unfavorable lipids (HDL) [Human]. HDL cholesterol decreased dose-dependently — an unfavorable lipid effect typical of androgenic agents.
- Class-level hepatotoxicity / DILI [Human — class]. The FDA has warned that products containing SARMs are associated with liver injury including cases of acute liver failure requiring hospitalization, plus increased risk of heart attack, stroke, and infertility.
- No long-term human safety data [Hypothesis]. Chronic hepatotoxicity, cardiovascular outcomes, fertility, and carcinogenicity for PF-06260414 specifically are not established — no data exist.
Contamination reality — a 'SARM' label is not a statement of contents
Van Wagoner et al. (JAMA 2017;318(20):2004-2010, PMID 29183075) chemically analyzed 44 products sold as SARMs: only 52% actually contained the labeled SARM, 39% contained a different unapproved drug, and 9% contained no active compound at all. A product sold as "PF-06260414" is therefore not reliably PF-06260414 — it may contain a different drug, or nothing. This is an independent hazard on top of the compound's own risks, and a common source of inadvertent anti-doping violations.
Legal status
Legality not assessed here
This page does not assess the legality of buying or possessing PF-06260414 in any specific country. What is documented: it is not an approved medicine, supplement, or food ingredient anywhere, it is an investigational compound sold otherwise only as a research reagent, and it becomes an unauthorised medicine the moment it is intended for human use. Separately, it is prohibited in sport by WADA at all times. "Research chemical" status is a legal and safety gray zone — it is not a signal of safety or approval, and this is not a "milder, safer, or legal alternative" to steroids. Check your own jurisdiction; this is not legal advice, and is not a claim that the compound is safe, legal, or beneficial to take. Dated 2026-07-10.
How it compares
PF-06260414 is often grouped with other SARMs and with non-SARM "research chemicals." The honest framing:
- Ostarine, Testolone (RAD-140), Ligandrol (LGD-4033), Andarine — other nonsteroidal SARMs that share PF-06260414's mechanism (AR modulation), testosterone- suppression risk, WADA S1.2 status, and lack of approval. Where several of those have extensive grey-market case-report data, PF-06260414's entire human record is one completed Phase 1 study — narrower, and with no efficacy data at all.
- Cardarine (GW-501516) and Stenabolic (SR9009) — frequently sold alongside SARMs but are NOT SARMs (a PPARδ agonist and a Rev-ErbA agonist, respectively). Different mechanisms entirely.
The decisive point: PF-06260414 is investigational, not approved for anything, reached only a single Phase 1 safety study, and has no human efficacy evidence for physique or performance. See the Muscle, growth & hormones overview.
Common misconceptions
- "PF-06260414 is a peptide." No. It is a synthetic nonsteroidal small molecule (C14H14N4O2S, 302.35 g/mol). It is covered here only because it is discussed and stacked with peptides.
- "It's a milder, safer, legal alternative to steroids." No. It is not approved, it suppresses natural testosterone, it lowers HDL cholesterol, and its most frequent adverse event in trial was elevated ALT (a liver enzyme). "SARM" does not mean "safe."
- "The muscle/performance benefits are proven in humans." No. The only human study measured safety, PK, and PD in healthy volunteers. There is no human efficacy trial for muscle or physical function — those benefits are not established.
- "It's an actively developed Pfizer drug." No. Pfizer ran one Phase 1 study and there is no public evidence of any further development; its status is effectively inactive.
- "Buying it as a 'research chemical' means it's clean and correctly dosed." No. Independent testing (JAMA 2017) found most products sold as SARMs were mislabeled, contained a different drug, or contained nothing.
This entry is educational and summarizes published research and public regulatory information as of the "updated" date above. It is not medical advice, not legal advice, a recommendation, or a guide to obtaining or using any substance.
References
- 1.Safety, Pharmacokinetic, and Pharmacodynamic Evaluation After Single and Multiple Ascending Doses of a Novel Selective Androgen Receptor Modulator in Healthy Subjects — Bhattacharya I, Tarabar S, Liang Y, Pradhan V, Owens J, Oemar B., Clinical Therapeutics, 2016. source
- 2.First-in-Human SAD/MAD Study of PF-06260414 in Healthy Men (NCT02070939) — Pfizer, ClinicalTrials.gov, 2016. source
- 3.PubChem CID 76071881 — PF-06260414 (C14H14N4O2S, CAS 1612755-71-1) — National Library of Medicine (PubChem), PubChem, 2026. source
- 4.PF-06260414 — androgen receptor modulator (CAS 1612755-71-1) — MedKoo Biosciences, MedKoo Biosciences product listing, 2026. source
- 5.Chemical Composition and Labeling of Substances Marketed as Selective Androgen Receptor Modulators and Sold via the Internet — Van Wagoner RM, Eichner A, Bhasin S, Deuster PA, Eichner D., JAMA, 2017. source
- 6.FDA Warns of Use of Selective Androgen Receptor Modulators (SARMs) Among Teens, Young Adults — U.S. Food and Drug Administration, FDA Consumer Updates, 2026. source
- 7.Selective Androgen Receptor Modulators (SARMs) — Prohibited Class: Anabolic Agents (S1.2) — U.S. Anti-Doping Agency (USADA), USADA, 2026. source
Frequently asked questions
- What is PF-06260414?
- A nonsteroidal selective androgen receptor modulator (SARM) — a small synthetic molecule (thiadiazinane-substituted isoquinoline-carbonitrile, C14H14N4O2S, CAS 1612755-71-1, PubChem CID 76071881), NOT a peptide — developed by Pfizer. It reached a single completed Phase 1 first-in-human study in healthy men (NCT02070939; Bhattacharya et al., Clin Ther 2016, PMID 27085586) and shows no public development beyond Phase 1. It is NOT an approved medicine for any use, including muscle growth, physique, or performance.
- Is PF-06260414 approved as a medicine, and where?
- No. PF-06260414 is investigational: it is being studied in human clinical trials but is not approved by any regulator and is not available as a licensed medicine.
- What is PF-06260414 studied for?
- PF-06260414 is most often discussed in the context of muscle & growth hormone. Research has examined muscle-growth-hormone. Being studied for an area does not mean it is proven or approved for it.
- Does PF-06260414 have human clinical trials?
- Yes. PF-06260414 is currently being studied in human clinical trials, but it is not yet approved.
Educational disclaimer. This article summarizes published research for informational purposes and is not medical advice. PF-06260414 is a research chemical not approved for human use. Consult a qualified healthcare professional before making health decisions.