LGD-4033 (Ligandrol) Research Overview (also known as Ligandrol, LGD4033, VK5211)
LGD-4033, also called Ligandrol or VK5211, is an investigational nonsteroidal selective androgen receptor modulator developed to stimulate anabolic signaling in skeletal muscle and bone while limiting androgenic activity in tissues such as the prostate. Early clinical research found dose-dependent increases in lean body mass, but also testosterone suppression and adverse lipid changes; it is not approved for human use, and products sold online may be mislabeled or contaminated.
Important scope note: LGD-4033 is an investigational research compound, not an approved medicine, dietary supplement, or established treatment for muscle loss, osteoporosis, hypogonadism, or athletic performance. The dosing, cycling, post-cycle therapy, and stacking information below describes practices discussed in research and online drug-use communities for educational purposes; it is not a recommendation or a substitute for medical supervision. Human clinical evidence is limited, and the risks of unsupervised use include endocrine suppression, adverse lipid changes, liver injury, cardiovascular complications, psychiatric effects, infertility, and exposure to inaccurately labeled products.
What Is LGD-4033?
LGD-4033 is a synthetic, nonsteroidal selective androgen receptor modulator, or SARM. It was developed by Ligand Pharmaceuticals as an orally active androgen-receptor ligand intended to produce anabolic effects in skeletal muscle and bone with less stimulation of androgen-sensitive tissues than conventional anabolic-androgenic steroids. The compound was subsequently advanced by Viking Therapeutics under the development code VK5211, particularly for clinical investigation in people recovering from hip fracture. Unlike testosterone or many anabolic steroids, LGD-4033 was designed to exploit tissue-selective androgen-receptor pharmacology rather than to provide systemic androgen replacement.
LGD-4033 is frequently described as one of the most clinically studied SARMs, although its human evidence base remains small compared with approved medicines. A short randomized trial in healthy men demonstrated measurable increases in lean body mass at doses substantially below those commonly promoted online, together with suppression of serum testosterone and changes in high-density lipoprotein cholesterol. Viking Therapeutics also studied VK5211 in a Phase 2 hip-fracture recovery program. Preclinical work suggested strong anabolic activity in muscle and bone, while oral administration and relatively high oral bioavailability made the compound attractive for development. These favorable pharmacologic properties do not establish safety or efficacy for bodybuilding, sports performance, or self-treatment.
The name Ligandrol is commonly used in supplement, bodybuilding, and research-chemical markets, but commercial identity does not guarantee chemical identity. Products labeled LGD-4033 may contain a different SARM, another active drug, an incorrect concentration, or no meaningful amount of the stated compound. "Research use only" labeling does not make human consumption lawful or safe. In sport, LGD-4033 is prohibited by the World Anti-Doping Agency at all times.
Research Indications
Lean Body Mass
Short-term human study findings
In a 21-day placebo-controlled study in healthy men, LGD-4033 produced dose-dependent increases in lean body mass.
Body-composition endpoint
The available clinical evidence is limited in duration and does not establish long-term efficacy, functional benefit, or safety.
Muscle Function
Androgen-receptor selectivity rationale
LGD-4033 is designed to act as a selective androgen-receptor modulator with tissue-selective anabolic activity in preclinical models.
Functional outcomes remain uncertain
Evidence for improved strength, athletic performance, recovery, or clinical physical function is insufficient and cannot be inferred from lean-mass change alone.
Clinical Development Applications
Muscle-wasting conditions
SARMs have been investigated as potential therapies for conditions involving muscle loss, but LGD-4033 is not approved for treatment of sarcopenia or cachexia.
No approved indication
LGD-4033 is not an FDA-approved medication and is prohibited in sport under World Anti-Doping Agency rules.
Pharmacology and Endocrine Effects
Hormonal suppression signal
Clinical exposure was associated with dose-dependent suppression of total testosterone, sex hormone-binding globulin, and high-density lipoprotein cholesterol.
The degree and duration of endocrine recovery after nonmedical use, prolonged use, or higher exposure are not well characterized.
Research Protocols
As reported in cited literature and research-community logs (see Research Citations below) — not a personal dosing recommendation.
| Research Application | Dose | Frequency | Route |
|---|
| Phase I pharmacokinetic study | 0.1 mg | Once daily for 21 days | Oral |
| Phase I dose cohort | 0.3 mg | Once daily for 21 days | Oral |
| Phase I dose cohort | 1.0 mg | Once daily for 21 days | Oral |
| Phase I dose cohort | 3.0 mg | Once daily for 21 days | Oral |
Timing
The documented human trial used once-daily administration for 21 days. These are study cohorts, not recommended nonmedical-use doses; no regimen is established as safe or effective outside controlled research.
Peptide Interactions
Combined androgenic exposure may increase endocrine, lipid, cardiovascular, hepatic, and other adverse-effect risks; supervised medical therapy should not be altered without a clinician.
Alcohol can worsen lipid and liver-related risk factors and may complicate assessment of adverse symptoms or laboratory abnormalities.
Avoid combining with agents associated with liver injury unless reviewed by a clinician, especially where liver enzymes are elevated or liver disease is present.
LGD-4033 may adversely affect HDL cholesterol; lipid results and prescribed cardiovascular treatment require clinician oversight.
Use is inappropriate during pregnancy and may interfere with reproductive endocrine management; discuss all hormone-active agents with a qualified clinician.
No specific pharmacologic interaction is established, but caffeine may aggravate palpitations, anxiety, or elevated blood pressure in susceptible individuals.
Reported Research Timeline
01Days 1–7 (reported in cited studies): no reliable subjective effect should be expected; early endocrine and lipid changes may occur without noticeable symptoms.
02Weeks 2–3 (reported in cited studies): the published human study observed dose-dependent changes in lean body mass over 21 days, alongside suppression of sex-hormone measures.
03Weeks 3–4 (reported in cited studies): changes in HDL cholesterol or other laboratory values may be measurable; subjective appearance or performance claims are not dependable safety indicators.
04Weeks 4–8 (reported in cited studies): effects from prolonged or higher-dose nonmedical exposure are not adequately characterized in controlled human studies.
05After discontinuation (reported in cited studies): hormonal recovery timing is variable and uncertain, particularly following nonclinical exposure; medical evaluation is appropriate for persistent symptoms.
06Long term (reported in cited studies): there are no adequate data establishing durable benefit, cardiovascular safety, reproductive safety, or risk profile with repeated use.
Safety Notes
Included for harm-reduction awareness only, in the event this compound is encountered outside its labeled research use. Inclusion here does not imply RUO Codes endorses, recommends, or instructs human use.
LGD-4033 is not approved for human therapeutic use and products sold as SARMs may be adulterated, mislabeled, or contain different active ingredients.
Published clinical data show dose-dependent suppression of testosterone-related measures and reductions in HDL cholesterol.
Avoid use during pregnancy, while trying to conceive, or during breastfeeding because reproductive and developmental safety are unknown.
People with cardiovascular disease, dyslipidemia, liver disease, prostate disease, or endocrine disorders should avoid unsupervised exposure.
LGD-4033 is prohibited at all times by anti-doping rules; athletes may face sanctions from detected use or contaminated supplements.
Seek Medical Attention If:
You develop chest pain, shortness of breath, fainting, a sustained rapid heartbeat, or symptoms suggestive of a stroke.
You experience yellowing of skin or eyes, dark urine, severe abdominal pain, persistent nausea, or unusual fatigue.
You develop severe mood changes, agitation, depression, suicidal thoughts, or other acute psychiatric symptoms.
You have persistent sexual dysfunction, testicular pain, breast changes, or other concerning endocrine symptoms after exposure.
Quality Indicators
Verified Marker
Batch-specific third-party COA
A credible certificate of analysis identifies the exact lot, test date, laboratory, sample identity, and quantitative result.
Verified Marker
Quantitative HPLC or LC-MS assay
Look for a quantitative chromatographic method that confirms LGD-4033 identity and reports measured potency rather than a generic purity claim.
Verified Marker
Accurate oral-unit content
For capsules or tablets, assay of finished dosage units and content-uniformity testing are more informative than testing only the raw powder.
Acceptable Range
Impurity and residual-solvent reporting
A useful report includes chromatograms, specified impurities, residual solvents, and clear analytical limits; these data are often absent from retail products.
Quality Concern
Vendor-issued or undated certificate only
A reusable, unverifiable, or non-lot-specific COA does not demonstrate identity, purity, dose accuracy, or absence of undisclosed drugs.
Research Citations
- The safety, pharmacokinetics, and effects of LGD-4033, a novel nonsteroidal oral selective androgen receptor modulator, in healthy young men.
Basaria, S., Collins, L., Dillon, E. L., et al., 2013, The Journals of Gerontology Series A - Selective androgen receptor modulators: clinical applications and emerging therapeutic potential.
Narayanan, R., Coss, C. C., Yepuru, M., et al., 2018, Endocrine Reviews - Selective androgen receptor modulators: current status and future perspectives.
Mohan, S., and Narayanan, R., 2018, Steroids - Chemical analyses of commonly available selective androgen receptor modulators.
Van Wagoner, R. M., Eichner, A., and Bhasin, S., 2017, JAMA - Adverse health consequences of performance-enhancing drugs: an Endocrine Society scientific statement.
Pope, H. G., Wood, R. I., Rogol, A., et al., 2014, The Lancet
Research Focus
muscle wasting, osteoporosis, hip fracture recovery, lean mass
Frequently Asked Questions
What should researchers watch for with LGD-4033 (Ligandrol)?
Included for harm-reduction awareness only, in the event this compound is encountered outside its labeled research use. Inclusion here does not imply RUO Codes endorses, recommends, or instructs human use.
What should researchers expect over time with LGD-4033 (Ligandrol)?
Days 1–7 (reported in cited studies): no reliable subjective effect should be expected; early endocrine and lipid changes may occur without noticeable symptoms.
How is LGD-4033 (Ligandrol) typically administered in research?
As reported in cited literature and research-community logs (see Research Citations below) — not a personal dosing recommendation.
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