RESEARCH MONOGRAPH · KDC-MN-269

LGD-3303

May 9, 2026 Kodiac biolabs Research Revised May 30, 2026 2 min read

Our opinion on this compound

41/100

Less-popular Ligand SARM with selectivity claims that the limited human data cant really evaluate

LGD-3303 is the Ligand SARM that didnt become a popular gray-market compound the way LGD-4033 did, and the published evidence base reflects that lower commercial interest. There's solid in vitro and animal characterization from Vajda, Lipinski and colleagues at Ligand around 2009, showing tissue-selective AR agonism with particularly favorable activity in bone models for osteoporosis indications. Then the development pivoted, and almost nothing on human pharmacology was published downstream.

The mechanism story is consistent with the broader class. Non-steroidal AR agonist, partial agonism in some assay readouts, preferential muscle and bone activity relative to prostate in rodent models. The differentiating selling point in the 2009 publications was particularly strong effects on cortical bone parameters and bone mineral density in ovariectomized rats, which is what made LGD-3303 attractive for osteoporosis development specifically.

What we like for narrow research use is that LGD-3303 is a useful comparator compound for studies looking at SARM tissue selectivity, particularly in bone biology contexts. The animal data on cortical bone effects is among the better characterized for the class.

What we dont like is that there's essentially nothing in the way of controlled human exposure data. The compound never went into formal phase 1, the published pharmacokinetic data is sparse, and the safety profile in humans is unknown. The HPG suppression characteristics in animal models suggest it should behave similarly to other SARMs in this respect, but that's extrapolation, not measurement.

The sparse consumer-scene presence of LGD-3303 compared to ostarine or LGD-4033 has both an upside and a downside. The upside is that adulteration and counterfeit pressure has been somewhat lower because the demand has been lower. The downside is that the limited gray-market presence means even less anecdotal feedback is available to triangulate from, which isnt evidence but does feed into how researchers contextualize use.

Sourcing for research-grade LGD-3303 is doable but vendor variability is real. HPLC purity verification and identity confirmation by mass spectrometry are necessary. The relative obscurity has limited the development of standardized analytical methods compared to more popular SARMs.

Honest take: real pharmacology, thin development history, interesting bone biology rationale, almost no human data. Useful as a research probe; treat as a hypothesis-generating tool, not a characterized compound.

Evidence: 20
Mechanism: 55
Reliability: 45
Safety: 45
Sourcing: 50
Value: 45
Signal: 40
Staying power: 30

Plain-language summary Intrigue 42 / 100

LGD-3303 is a less-well-known SARM from Ligand Pharmaceuticals, developed as a candidate for osteoporosis. In ovariectomized rat models (the standard postmenopausal-bone preclinical model) it produced bone anabolic effects comparable to or exceeding raloxifene, with relatively favorable bone-versus-muscle selectivity. Phase 1 human studies were conducted but the compound did not advance further, and full clinical results were never published. It is occasionally encountered as a research chemical but is much less common than ostarine or ligandrol. Limited human data and an inactive development program limit clinical relevance. Not stocked by Kodiac. This monograph is provided for research and educational reference.

Intrigue 0–100 blends mechanism novelty, evidence strength, and translational potential. Kodiac editorial, not peer-reviewed.

Selective androgen receptor modulator

A non-steroidal SARM developed by Ligand Pharmaceuticals for osteoporosis; less studied than ligandrol.

Abstract

LGD-3303 (9-chloro-2-ethyl-1-methyl-3-(2,2,2-trifluoroethyl)-3H-pyrrolo[3,2-f]quinolin-7(6H)-one; molecular formula C16H14ClF3N2O; molecular weight 342.74) is a non-steroidal SARM developed by Ligand Pharmaceuticals as a candidate for osteoporosis. Preclinical studies in ovariectomized rats demonstrated strong bone anabolic activity comparable to or exceeding raloxifene at appropriate doses, with reduced prostate effects. Tissue selectivity profile favors bone over muscle within the SARM class. Phase 1 human studies were conducted but the compound did not advance to phase 2. The compound retains research utility for bone-focused SARM pharmacology and is occasionally used recreationally. Plasma half-life is approximately 24 hours.

Mechanism of action

Non-steroidal SARM with bone-focused tissue selectivity. Preclinical efficacy comparable to raloxifene in ovariectomized rat osteoporosis models.

Reported research dose ranges

Recreational use commonly 10 to 30 mg in the published literature; preclinical osteoporosis dosing 1 to 10 mg/kg.

References

Vajda EG, et al. Pharmacokinetics and pharmacodynamics of LGD-3303 in male rats. Pharm Res 2009.
Allan G, et al. LGD-3303 stimulates androgenic activity in muscle and bone with reduced prostate effects. J Steroid Biochem Mol Biol 2009.
Mohler ML, et al. Nonsteroidal selective androgen receptor modulators (SARMs). J Med Chem 2009.

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KDC-MN-269

The full reference document is provided strictly for research use only. It reports research dose ranges from the published literature, not instructions for use in humans or animals.

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FOR RESEARCH USE ONLY. Not for medical, diagnostic, or therapeutic purposes. Not for human consumption. All information is provided for research and educational purposes only.

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LGD-3303

Abstract

Mechanism of action

Reported research dose ranges

References

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Abstract

Mechanism of action

Reported research dose ranges

References

Read the full monograph

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