LGD-4033, also known by its development name Ligandrol, is one of the most studied non-steroidal Selective Androgen Receptor Modulators (SARMs) in the preclinical and early clinical literature. Originally developed by Ligand Pharmaceuticals and subsequently advanced by Viking Therapeutics under the designation VK5211, LGD-4033 has been the subject of pharmacokinetic studies, dose-escalation trials, and numerous preclinical investigations into its anabolic properties.
This guide provides a research-oriented overview of LGD-4033: its mechanism of action, what the published literature has documented, its pharmacokinetic profile, and practical considerations for researchers. This is strictly an educational reference — LGD-4033 is not approved for human therapeutic use.
If you’re new to the SARM compound class, our Complete Guide to SARMs provides foundational context on how these compounds work.
What Is LGD-4033?
LGD-4033 is a non-steroidal SARM belonging to the arylpropionamide class of androgen receptor ligands. It binds to the androgen receptor with high affinity and selectivity, displaying full agonist activity in muscle and bone tissue and partial agonism (or antagonism, depending on the model) in other androgen-sensitive tissues.
It was originally synthesized as part of Ligand Pharmaceuticals’ SARM program, targeting conditions associated with muscle wasting — including cancer cachexia, sarcopenia, and osteoporosis. LGD-4033’s distinguishing characteristics include its high binding affinity for the androgen receptor, oral bioavailability without chemical modification, and a relatively favorable tissue selectivity profile in rodent models compared to non-selective androgens.
Mechanism of Action
LGD-4033 binds competitively to the androgen receptor (AR) — the same intracellular receptor targeted by endogenous testosterone and dihydrotestosterone (DHT). When LGD-4033 occupies the ligand-binding domain of the AR, it induces a specific conformational change in the receptor protein that determines which coactivator and corepressor proteins bind to the complex, controlling which androgen response element (ARE) sequences are transcribed in the nucleus.
In skeletal muscle tissue, LGD-4033 acts as a full agonist, activating protein synthesis pathways. In bone tissue, it shows similarly agonist activity in preclinical models. In prostate tissue, LGD-4033 has shown reduced androgenic activity compared to testosterone in male rodent models — a primary design goal of its development.
Unlike testosterone, LGD-4033 does not convert to estrogen via aromatase, and it does not convert to DHT via 5-alpha reductase.
Pharmacokinetics
The pharmacokinetic profile of LGD-4033 has been documented in both preclinical animal studies and a published Phase I human study (Basaria et al., 2013, The Journals of Gerontology).
Oral bioavailability: LGD-4033 demonstrates high oral bioavailability in both rodent models and humans. The Basaria et al. study observed dose-proportional increases in plasma concentration across dose levels from 0.1 mg to 1.0 mg/day.
Half-life: The published human pharmacokinetic data reports an approximate elimination half-life of 24–36 hours, meaning steady-state plasma concentrations are typically achieved within approximately one week of daily dosing.
Metabolism: LGD-4033 is metabolized in the liver via hydroxylation and glucuronidation. Its metabolites have been characterized in urine, relevant to researchers involved in biomarker or detection methodology studies.
What the Preclinical Literature Documents
Lean body mass: In orchiectomized (testosterone-depleted) male rats, LGD-4033 produced dose-dependent increases in muscle mass at doses substantially lower than testosterone propionate, with reduced effect on prostate weight — consistent with the SARM tissue-selectivity hypothesis.
Bone density: Preclinical models examining ovariectomized female rats showed LGD-4033 effects on bone mineral density and markers of bone formation at low oral doses.
Phase I human study: Basaria et al. (2013) reported on a randomized, double-blind, placebo-controlled Phase I study in 76 healthy male volunteers receiving placebo or LGD-4033 at 0.1, 0.3, or 1.0 mg/day for 21 days. The study documented dose-dependent increases in lean body mass and decreases in total and free testosterone due to HPG axis suppression, with recovery within 5 weeks of stopping. No drug-related serious adverse events were reported.
Phase II (VK5211): Viking Therapeutics advanced LGD-4033 into a Phase II trial targeting patients recovering from hip fracture surgery. Results published in 2017 reported statistically significant increases in lean body mass in the treated group.
HPG Axis Suppression — A Critical Research Variable
A consistently documented finding across LGD-4033 studies is suppression of the hypothalamic-pituitary-gonadal (HPG) axis. LGD-4033 suppresses luteinizing hormone (LH) and follicle-stimulating hormone (FSH), reducing endogenous testosterone production. This is an expected pharmacological consequence of androgen receptor agonism — any compound that activates ARs sends negative feedback signals to the hypothalamus and pituitary.
For researchers interested in compounds that stimulate rather than suppress endogenous testosterone production, Enclomiphene Citrate — a selective estrogen receptor modulator — operates through the opposite mechanism, increasing LH and FSH output.
LGD-4033 vs. Other SARMs in the Literature
LGD-4033 vs RAD-140: Both are full AR agonists in muscle tissue. LGD-4033 has a more extensive published literature and has progressed further in clinical trials. RAD-140 has shown higher anabolic-to-androgenic ratios in some preclinical models but has less published human data.
LGD-4033 vs RAD-150: RAD-150 (TLB-150) is a benzoate ester of RAD-140, designed to alter its pharmacokinetic profile. Research interest in RAD-150 relates to whether the esterified form provides different release characteristics compared to the parent compound.
Sourcing LGD-4033 for Research
For researchers requiring LGD-4033 for preclinical studies, compound identity verification and purity documentation are essential prerequisites for reproducible research. Chemyo Sarms supplies LGD-4033 as a research-grade compound with batch-specific third-party Certificate of Analysis (COA) documentation confirming identity, purity, and concentration.
→ View LGD-4033 (Ligandrol) research compound
Frequently Asked Questions
What is LGD-4033 used for in research?
LGD-4033 is studied primarily in the context of conditions involving muscle wasting and bone density loss. Preclinical research has examined its anabolic effects in models of androgen deficiency, sarcopenia, and post-surgical recovery.
Does LGD-4033 suppress testosterone?
Yes. Published research consistently documents suppression of LH, FSH, and endogenous testosterone during LGD-4033 administration, with recovery documented after cessation. This should be accounted for in experimental design.
Is LGD-4033 approved for human use?
No. LGD-4033 has not received FDA approval for therapeutic use. It is an unapproved investigational compound sold strictly for research purposes.
What is the difference between LGD-4033 and Ligandrol?
They are the same compound. “Ligandrol” is the common name given to LGD-4033 during its development at Ligand Pharmaceuticals, where the “LGD” designation originates.
Where can I find published research on LGD-4033?
The primary peer-reviewed reference is Basaria et al. (2013) in The Journals of Gerontology. Additional preclinical data is available via PubMed searches for “LGD-4033” or “VK5211.”
LGD-4033 is sold by Chemyo Sarms strictly as a research compound for laboratory use. It is not intended for human consumption. For educational reference only.