LGD-4033 (Ligandrol): Strength-Class SARM
Last updated: March 2026
1.21kg of lean mass in just 21 days at 1mg/day — the Phase 1 data that put Ligandrol on the map. Stronger than Ostarine, more suppressive, and still nowhere near FDA approval. Here's the research.
(Daily)
(1mg, Phase 1 Trial)
(Long-Acting)
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How LGD-4033 Works
LGD-4033 is a non-steroidal SARM with high affinity and selectivity for the androgen receptor. It demonstrates stronger binding affinity than Ostarine, which translates to more potent anabolic effects at lower doses — but also more pronounced hormonal suppression.
LGD-4033 binds the androgen receptor with a Ki of approximately 1 nM — among the highest affinities of any SARM. This tight binding translates to potent activation of anabolic pathways in muscle and bone at very low doses (effects visible at 0.3mg/day in trials). The selectivity ratio favors muscle over prostate, but less so than Ostarine.
The Basaria Phase 1 trial showed a clear dose-response: 0.1mg (+0.2kg LBM), 0.3mg (+0.6kg LBM), 1.0mg (+1.21kg LBM) over just 21 days. This linear response at low doses suggests even higher gains at research doses (5-10mg), though no controlled data exists at these levels. Mechanism involves enhanced nitrogen retention and mTOR pathway activation.
Viking Therapeutics is developing VK5211 (LGD-4033) specifically for recovery from hip fracture surgery. The rationale: SARMs can preserve and build lean mass during the immobilization period after surgery, potentially reducing recovery time and fall risk. Phase 2 hip fracture trials showed positive results on lean body mass endpoints.
LGD-4033 causes significant dose-dependent suppression of the hypothalamic-pituitary-gonadal axis. At 1mg/day for 21 days, total testosterone dropped ~50%, free testosterone dropped ~40%, and LH and FSH were significantly reduced. This is more suppressive than Ostarine at equivalent timeframes. Recovery occurred within 56 days of cessation in the trial.
What the Research Shows
LGD-4033 has Phase 1 safety data and Phase 2 data in hip fracture patients (VK5211). The Phase 1 trial by Basaria et al. is the most cited SARM trial in the literature.
Key trial: Basaria et al. (2013) — 76 healthy men, randomized, double-blind, placebo-controlled. Doses: 0.1, 0.3, and 1.0 mg/day for 21 days. This is the gold-standard Phase 1 SARM trial and the basis for most LGD-4033 research dose extrapolations.
Side Effects & Risks
LGD-4033 is stronger than Ostarine — which means the side effect profile is also more pronounced, especially at research doses above the clinical 1mg.
- Significant testosterone suppression (~50% at 1mg/day)
- LH, FSH, and SHBG all suppressed dose-dependently
- Case reports of drug-induced liver injury (DILI) at higher doses
- ALT/AST elevation — hepatotoxicity concerns at 5-10mg+
- PCT commonly recommended after research-dose cycles
- Recovery to baseline took ~56 days at clinical doses
- HDL cholesterol reduction observed — lipid profile impact
- Total cholesterol changes — cardiovascular risk factor
- Water retention reported anecdotally at higher doses
- Headaches, fatigue during suppression window
- Potential prostate effects less studied than Ostarine
- Long-acting (36hr t½) — slow washout if problems occur
Study Citations
Key Takeaways
- Phase 1 RCT confirmed dose-dependent lean mass gains in healthy men
- 1.21kg LBM in 21 days at just 1mg/day — potent at low doses
- Viking Therapeutics advancing VK5211 for hip fracture recovery
- 36-hour half-life allows once-daily dosing
- Stronger than Ostarine mg-for-mg, but more suppressive
- Hormone recovery occurred within ~56 days in Phase 1
- No controlled data at research doses (5-10mg) — only Phase 1 at ≤1mg
- Hepatotoxicity risk at higher doses — case reports are concerning
- Long-term cardiovascular impact from chronic lipid changes
- Whether PCT accelerates recovery vs natural recovery
- Research chemical purity and consistency issues
- Cancer risk with chronic androgen receptor activation
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This page is for educational and informational purposes only. It is not medical advice. LGD-4033 (Ligandrol/VK5211) is NOT FDA approved for human use. It is a research chemical and is not a dietary supplement. The FDA has issued warning letters to companies marketing SARMs. All SARMs are banned by WADA in competitive sport. Always consult a qualified healthcare provider. HighPeptides does not sell SARMs or endorse their use outside of legitimate research contexts.