Educational reference only. Nothing on this page constitutes medical advice or encourages personal use of this compound. Always consult a qualified healthcare provider before any decision involving your health.

LGD-4033 / Ligandrol

LGD-4033 · Ligandrol · VK5211 · SARM

Animal replicated

Research chemicalSARM Selective Androgen Receptor Modulator Small Molecule

RouteOralGray-market only

Evidence grade: Animal replicated

Effect demonstrated in multiple animal studies; human data sparse or extrapolated. Grades summarize evidence quality, not whether a compound is appropriate, legal, or risk-free.

At a glance

What it is: Nonsteroidal selective androgen receptor modulator (SARM); orally active small-molecule androgen receptor ligand.
Why people use it: Used primarily for muscle and performance and hormonal support.

If you only read one thing

LGD-4033 holds a paradoxical position in the SARM evidence landscape: it has the most clinical trial data of any SARM, but that data was generated at doses that are a fraction of what the community uses. The Phase 1 trial at 0.1-1 mg/day with no significant liver enzyme changes is genuinely reassuring for that dose range. It is not reassuring for the 5-20 mg/day doses that community users employ. The Phase 2 hip fracture trial (VK5211) at efficacy doses in elderly patients showed no drug-related serious adverse events — but elderly hip fracture patients and young men seeking body composition enhancement represent different populations with different baseline risks. The community's appeal to LGD-4033's 'clinical data' as a safety endorsement conflates evidence from one dose range with use at a categorically different dose range. Understanding this distinction is the most important critical thinking exercise for anyone considering LGD-4033.

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Published literature

2human RCTs1human study0animal0in vitro

Evidence reality check

Human evidence

3 human studies

2 randomized; 1 observational.

Preclinical base

0 lab signals

0 animal; 0 in-vitro/mechanistic.

Risk posture

No major flags listed

Review route-specific cautions before use.

Categories

Muscle & Performance Hormonal & HPTA

Properties

Active malignancy: hard stopWADA S1✓ Human RCTHPTA: suppressiveNot injectable

Half-life

Pharmacokinetics: half-life 24-36 hours

Evidence

CAnimal replicated

The Most Important Framing for This Chapter

The foundational Phase 1 clinical trial used doses of 0.1, 0.3, and 1 mg/day for 21 days. The maximum Phase 1 dose was 1 mg/day. Community users typically take 5-20 mg/day for 6-8 weeks. This means community doses are 5 to 200 times higher than the clinically studied doses, and 2-4 times longer in duration. The safety profile documented in the clinical trials is at 0.1-1 mg — not at 5-20 mg. The absence of serious liver enzyme changes in the Phase 1 trial at 0.1-1 mg does not confirm safety at 5-20 mg community doses. This dose gap is the single most important context for interpreting the LGD-4033 evidence.

The Phase 1 Trial Results

Basaria S, Collins L, Dillon EL, et al. (2013). The Safety, Pharmacokinetics, and Effects of LGD-4033 in Healthy Young Men. Journals of Gerontology: Series A. 68(1):87-95. n=76 healthy men; randomized; doses 0.1, 0.3, 1 mg/day for 21 days. Results: lean mass increased dose-dependently — +1.21 kg at 1 mg/day over 21 days (statistically significant vs placebo); fat mass unchanged; no significant change in serum aminotransferases (liver enzymes) at any dose; dose-dependent suppression of total testosterone, free testosterone, and SHBG; no serious adverse events. This is the best quality human safety data for LGD-4033 — and it was at 0.1-1 mg.

Phase 2 Hip Fracture — VK5211

Viking Therapeutics Phase 2 (ASBMR 2018; NCT02578095): hip fracture patients ≥65 years; 12 weeks; VK5211 (LGD-4033) vs placebo; primary endpoints: lean body mass and functional outcomes. Results: VK5211 significantly improved lean body mass vs placebo; no drug-related serious adverse events; encouraging safety and tolerability. This is the most advanced clinical trial for LGD-4033 and the most clinically relevant demonstration that the compound produces meaningful lean mass effects in an elderly, compromised population. Development of VK5211 by Viking continues but no Phase 3 has been announced.

Doping Violations

LGD-4033 has been involved in multiple high-profile athlete doping violations: Canelo Álvarez (boxing, 2018) — tested positive; attributed to contaminated Mexican beef; VADA and WBC accepted the contamination explanation; case ultimately resolved without suspension. Multiple NRL (National Rugby League) rugby players 2018-2019. Tennis players and track and field athletes. The Canelo case is the most prominent and illustrates the 'contaminated supplement' defense that has been used in multiple SARM cases. WADA S1.2 — absolute ban in and out of competition.

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