Ligandrol (LGD-4033)
LGD-4033 · LGD4033
Ligandrol (LGD-4033, also known as VK5211 in its later clinical development) is a non-steroidal selective androgen receptor modulator (SARM) originally developed by Ligand Pharmaceuticals and subsequently licensed to Viking Therapeutics for clinical evaluation. It was investigated for age-related muscle loss, hip-fracture recovery, and cancer-related muscle wasting. Among SARMs it is considered one of the strongest and most androgenic per milligram, providing meaningful lean mass accrual at low doses (1mg) in controlled human trials.
Once daily. THE PHASE 1 MAXIMUM WAS 1 mg FOR 21 DAYS, and the completed Phase 2 (VK5211, NCT02578095) went to 2 mg for 12 weeks - that 2 mg is the highest dose ever given to a human. Commonly circulated 5-20 mg doses are entirely unstudied, and drug-induced liver injury case reports exist at those levels. Suppression of testosterone, SHBG and FSH was dose-dependent even at 1 mg.
Start here. Every protocol below is ordered lowest-first. Begin at the smallest effective dose, hold about a week to assess tolerance, and step up only if needed.
How it works
Ligandrol binds the androgen receptor (AR) with high affinity and acts as a tissue-selective partial agonist. Its binding conformation preferentially drives anabolic signaling in skeletal muscle and bone while producing less androgenic activity in prostate, sebaceous glands, and hair follicles compared to testosterone. It is considered more potent per milligram than ostarine for lean mass accrual.
As a non-steroidal compound it does not aromatize to estrogen and does not convert to DHT, eliminating typical aromatase-driven and 5-alpha-reductase-driven side effects at standard doses. However, higher-dose or longer cycles can still produce indirect estrogenic effects via downstream HPT suppression and aromatization of residual endogenous androgens.
Ligandrol produces dose-dependent and often substantial suppression of endogenous testosterone, luteinizing hormone (LH), and follicle-stimulating hormone (FSH) - more than ostarine at equivalent doses. Post-cycle therapy with a SERM (Nolvadex or Clomid) is standard for non-TRT users. Hepatic effects are usually mild at therapeutic doses but FDA has reported serious drug-induced liver injury cases in gray-market supplement users.
What to expect
First 1-2 weeks: faster onset than ostarine. Strength and scale improvements often apparent by the end of week 2.
Weeks 3-5: visible muscle gain, body composition improvement even at maintenance calories, continued strength curve. Mid-cycle labs appropriate.
Weeks 6-8: peak benefits realized. Cycle end recommended by week 8 to limit suppression depth. PCT begins immediately after last dose.
Evidence
References for this compound are being re-checked against their source records. We are not showing them until each one is confirmed to support the claim it sits under.
Side effects & safety
Commonly reported
- Suppression of endogenous testosterone (more pronounced than ostarine, usually reversible with PCT)
- Lipid profile changes (HDL drop)
- Mild ALT/AST elevation
- Mild water retention in some users
Less common & notes
- Mood changes (irritability, emotional flatness), libido changes (usually dip during suppression), mild headache, hair thinning in genetically predisposed users, mild blood pressure elevation.
- In women: virilization risk at any meaningful dose - generally not recommended for women.
- FDA has reported cases of serious drug-induced liver injury in gray-market supplement users; product contamination is a major confounder but direct hepatotoxicity cannot be ruled out.
- Rare: gynecomastia-like symptoms at higher doses via downstream estradiol shifts.
Pharmacokinetics
High oral bioavailability
Per dose - supports once daily dosing
Hepatic metabolism via CYP3A4. Renal excretion of metabolites.
Storage. Store at controlled room temperature (20-25°C / 68-77°F). Protect from moisture and light. Keep capsules in original container with desiccant when available. Liquid suspensions should be kept sealed and used within 12 months of opening. Shelf life typically 2-3 years from manufacture date for capsules, 1-2 years for liquid. Keep out of reach of children.
Regulatory status
Ligandrol (LGD-4033) is NOT FDA-approved for any indication. The FDA has issued public warnings citing case reports of liver injury in supplement users. Classified as a research chemical in the United States - not a controlled substance federally as of this writing, but banned by WADA, USADA, the NCAA, and most professional sports leagues. Some US states have introduced legislation restricting SARM sales. Use falls outside regulated medical practice.
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