LGD-4033 Overview, Dosing & Safety | Peptide Database

LGD-4033 (Ligandrol)

Selective Androgen Receptor Modulator | Lean Mass

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LGD-4033 (Ligandrol) is a nonsteroidal investigational selective androgen receptor modulator (SARM) originally developed by Ligand Pharmaceuticals and later licensed to Viking Therapeutics (under the designation VK5211). It is one of the most widely studied SARMs in clinical trials, having completed Phase 1 safety studies in healthy volunteers and a Phase 2 trial evaluating its efficacy in patients recovering from hip fracture surgery. LGD-4033 was designed to provide anabolic benefits, specifically increased lean muscle mass and improved physical function, with reduced androgenic side effects compared to testosterone. In clinical studies, it demonstrated dose-dependent increases in lean body mass, leg press strength, and stair-climbing speed in hip fracture patients. LGD-4033 is broadly considered the most potent SARM for lean mass accrual, exceeding Ostarine (MK-2866) in anabolic potency at comparable doses. Despite promising clinical data, LGD-4033 is not approved by any regulatory agency for any medical indication. Its widespread use in performance enhancement contexts is based on a combination of clinical trial data, preclinical studies, and anecdotal reports.

LGD-4033 binds to the androgen receptor with high affinity (Ki of approximately 1 nM), functioning as a potent and selective agonist in muscle and bone tissue. Like other SARMs, its tissue selectivity is mediated by differential cofactor recruitment: upon binding to the AR, LGD-4033 induces a receptor conformation that preferentially recruits coactivators expressed in skeletal muscle and bone, while showing minimal agonist activity in androgen-sensitive tissues such as the prostate and skin. In preclinical studies, LGD-4033 produced dose-dependent increases in muscle mass (levator ani weight) with significantly less stimulation of prostate weight compared to testosterone. At the molecular level, AR activation by LGD-4033 drives gene transcription pathways involved in protein synthesis, nitrogen retention, and myogenic differentiation in skeletal muscle. The compound also promotes osteoblast activity and bone mineral density through AR signaling in bone tissue. LGD-4033 does not undergo aromatization to estrogen and is not a substrate for 5-alpha reductase, so it does not produce estrogenic side effects (gynecomastia, water retention from estrogen) or DHT-mediated side effects (prostate enlargement, androgenic alopecia). However, as a potent exogenous AR agonist, LGD-4033 suppresses endogenous testosterone production through negative feedback on the hypothalamic-pituitary-gonadal (HPG) axis in a dose-dependent manner. This suppression is generally considered more pronounced than that caused by Ostarine at equivalent effective doses, consistent with its greater AR binding affinity and anabolic potency.

Molecular Data

Research Indications

LGD-4033 is widely regarded as the most potent SARM for lean mass accrual. In the Phase 2 VK5211 trial in hip fracture patients, subjects receiving 1 mg/day gained an average of 1.21 kg of lean body mass over 12 weeks. Higher doses in healthy volunteer studies have shown even greater lean mass increases. Users consistently report LGD-4033 as superior to Ostarine for mass-building purposes.

Clinical trial data demonstrated statistically significant improvements in leg press strength in hip fracture patients treated with LGD-4033. Anecdotal reports consistently describe notable strength increases within 3-4 weeks, particularly in compound movements. Strength gains are dose-dependent.

The anabolic activity of LGD-4033 without estrogenic water retention makes it suitable for simultaneous lean mass gain and fat reduction. Some water retention can occur due to the compound itself (non-estrogenic mechanism), but overall body composition changes favor a recomposition effect. Clinical data shows favorable shifts in lean-to-fat mass ratio.

Viking Therapeutics conducted a Phase 2 trial (VK5211) evaluating LGD-4033 in patients recovering from hip fracture surgery. The trial met its primary endpoint, demonstrating dose-dependent increases in lean body mass at 12 weeks. Secondary endpoints including leg press strength and stair-climbing speed also showed statistically significant improvements versus placebo.

Originally developed for conditions involving muscle wasting and age-related muscle loss. Preclinical and early clinical data support the potential to preserve or restore muscle mass in catabolic states. The hip fracture trial results are directly relevant to sarcopenia and frailty in elderly populations.

Preclinical data demonstrates that LGD-4033 increases bone mineral density and bone formation markers through direct AR-mediated signaling in osteoblasts. While no dedicated human trial has been completed for this indication, the mechanism supports potential utility in osteoporosis, particularly in populations where traditional androgen therapy is contraindicated.

Dosing Protocols

LGD-4033 is administered exclusively via the oral route. It is available as a liquid solution (typically dissolved in PEG-400, ethanol, or DMSO carriers) or in capsule form from research chemical suppliers. The compound has high oral bioavailability and its half-life of approximately 24-36 hours supports once-daily dosing. Steady-state plasma concentrations are typically achieved within 5-7 days of consistent dosing.

Research Dose - Conservative

5 mg/day

Once daily

Oral (liquid or capsule)

Research Dose - Moderate

10 mg/day

Research Dose - Upper Range

15-20 mg/day

Interactions

What to Expect

Side Effects & Safety

Common Side Effects

Testosterone suppression (dose-dependent; more suppressive than Ostarine at equivalent doses, occurs in most users by week 4-6)

Water retention (non-estrogenic mechanism, typically mild to moderate, contributes to scale weight increase)

HDL cholesterol reduction (dose-dependent lipid impact observed in clinical trials)

Headaches (most common in the first 1-2 weeks, usually transient)

Fatigue or lethargy (related to testosterone suppression, typically becomes noticeable mid-cycle)

Reduced libido (related to HPG axis suppression, severity varies by dose and individual)

Stop Signs - Discontinue if:

Jaundice (yellowing of skin or eyes) indicating significant liver injury

Severe or persistent lethargy unresponsive to rest

Chest pain, tightness, or palpitations

Dark-colored urine (potential sign of liver damage or rhabdomyolysis)

Severe abdominal pain or persistent nausea/vomiting

Signs of allergic reaction: rash, swelling, difficulty breathing

Significant edema or rapid unexplained weight gain

Contraindications

Pre-existing liver disease or elevated liver enzymes at baseline

Hormone-sensitive cancers (prostate cancer or other androgen-driven malignancies)

Pregnancy or potential pregnancy (teratogenic risk from androgen receptor agonism)

Breastfeeding

Age under 25 (incomplete endocrine system maturation and higher risk of HPG axis disruption)

Concurrent use of hepatotoxic medications without medical supervision

Known cardiovascular disease (insufficient long-term safety data for this population)

History of significant lipid abnormalities (LGD-4033 suppresses HDL)

Quality Checklist

Good Signs

Third-party lab tested with certificate of analysis (COA) showing purity above 98%

Clearly labeled with compound name, concentration, batch number, and expiration date

Solution is clear and free of particulate matter or discoloration

Sold as a research chemical with appropriate disclaimers (not marketed for human consumption)

Supplier provides HPLC or mass spectrometry verification of identity and purity

Warning Signs

No third-party testing or certificate of analysis available

Sold in pre-made capsules without verifiable dosing accuracy

Concentration claims that vary between batches from the same supplier

Marketed with explicit performance enhancement claims (regulatory red flag)

Unusually low pricing compared to established research chemical suppliers

Bad Signs

Cloudy, discolored, or precipitated solution indicating degradation or contamination

No labeling, incorrect labeling, or missing batch/lot information

Supplier has no verifiable reputation, reviews, or testing history

Product tested by independent labs showing underdosed, mislabeled, or contaminated contents

Contains unlisted active ingredients or adulterants (a well-documented problem in the SARM market)

Sold by a source that also sells controlled substances (legal risk indicator)

Frequently Asked Questions

Do I need PCT after an 8-week LGD-4033 cycle?

PCT is generally recommended for cycles of 10+ mg/day or 8+ weeks in duration, though bloodwork at week 4-6 will guide the decision. If testosterone drops significantly (under 300 ng/dL), a short PCT with enclomiphene 12.5-25 mg/day for 4-6 weeks starting 3-5 days after the final dose accelerates recovery. At lower doses (5-10 mg) for shorter cycles, recovery may occur naturally within 4-6 weeks.

Can I stack LGD-4033 with RAD-140?

Not recommended. Both are potent SARMs that independently suppress testosterone, and stacking them produces compounding HPTA suppression without proportional additional muscle gains. If you choose to stack them anyway, run both at reduced doses (e.g., 5 mg LGD + 10 mg RAD) and expect significantly more suppression and side effects—full-dose PCT is mandatory afterward.

How long does it take to see lean mass gains on LGD-4033?

Noticeable strength increases typically appear within 3-4 weeks, while measurable lean mass gains (1-2 kg) become visible by week 4-6 on standard 10-15 mg doses with proper training and nutrition. Full cycle results (2-4 kg) are most apparent at 6-8 weeks; gains are dose-dependent and plateau if you extend beyond 8-10 weeks without additional compounds.

Does LGD-4033 cause water retention like testosterone?

LGD-4033 causes mild to moderate non-estrogenic water retention through the compound itself, not through aromatization. You'll see scale weight increase that's a mix of lean tissue and water (typically 5-10 lbs over 8 weeks), but the appearance is leaner than testosterone because there's no estrogen-driven subcutaneous bloat—most of the water retention is intramuscular.

References

First-in-human Phase 1 randomized, double-blind, placebo-controlled study of LGD-4033 in 76 healthy young men. LGD-4033 was well tolerated with no serious adverse events. Dose-dependent increases in lean body mass were observed (up to 1.21 kg at 1.0 mg/day over 21 days). Testosterone, FSH, and SHBG were suppressed in a dose-dependent manner, with recovery after discontinuation. No significant changes in PSA, hematocrit, or liver enzymes were observed.

Phase 2 double-blind, placebo-controlled trial of VK5211 (LGD-4033) in 108 patients recovering from hip fracture surgery. All three dose groups (0.5 mg, 1.0 mg, 2.0 mg) showed statistically significant increases in lean body mass versus placebo at 12 weeks. The 1.0 mg group also demonstrated significant improvements in functional measures including leg press strength and stair-climbing speed. The compound was well tolerated across all dose groups.

Comprehensive review of SARM pharmacology and clinical development. Discusses the mechanism of tissue selectivity, preclinical and clinical efficacy data for various SARMs including LGD-4033, and the therapeutic potential for muscle wasting, osteoporosis, and frailty. Notes LGD-4033 as one of the most clinically advanced SARMs with robust Phase 1 and Phase 2 data.

Case series documenting clinically significant drug-induced liver injury (DILI) in individuals using SARMs. While RAD-140 was more frequently implicated, LGD-4033 was also associated with hepatotoxicity events. The cases highlight the risk of using unregulated SARM products, which may contain impurities or undisclosed compounds that exacerbate liver injury risk.

Detailed analysis of body composition outcomes from the Phase 2 VK5211 hip fracture trial. Confirmed dose-dependent increases in appendicular lean mass measured by DXA, with the 1.0 mg dose group showing the most favorable overall profile of efficacy and safety. Functional improvements correlated with lean mass gains, supporting the clinical relevance of body composition changes.

Related Peptides

MK-677 (Ibutamoren) is one of the most common compounds stacked with LGD-4033. MK-677 increases growth hormone and IGF-1 through ghrelin receptor agonism, complementing the AR-mediated anabolic effects of LGD-4033. The combination may enhance lean mass accrual, recovery, sleep quality, and joint health. MK-677 does not suppress testosterone, making it a useful adjunct during and after SARM cycles. Note that MK-677 can increase appetite and water retention independently.

Enclomiphene is commonly used as post-cycle therapy (PCT) following LGD-4033 cycles to restore endogenous testosterone production. A typical PCT protocol is 12.5-25 mg/day enclomiphene for 4-6 weeks, starting approximately 2-3 days after the last LGD-4033 dose (the shorter half-life of LGD-4033 compared to RAD-140 means PCT can begin sooner). Some users also run low-dose enclomiphene on-cycle to mitigate suppression, though this approach is less studied.

Disclaimer

This information is for educational and research purposes only. Consult a healthcare professional before use.