LGD-4033, also known as ligandrol, is an experimental drug in the class of compounds called selective androgen receptor modulators (SARMs). It binds to the same receptors in your body that testosterone does, but it was designed to target muscle and bone tissue while having less effect on organs like the prostate or liver. LGD-4033 is not approved by the FDA for any medical use, and it is illegal to sell as a dietary supplement in the United States.
How LGD-4033 Works in the Body
Your body has androgen receptors in many tissues, including muscle, bone, fat, and reproductive organs. Testosterone activates all of them. LGD-4033 was engineered to preferentially activate androgen receptors in muscle and bone while producing weaker effects elsewhere. That selectivity is the core idea behind all SARMs: deliver the muscle-building benefits of androgens without the full range of side effects that come with anabolic steroids.
In practice, though, the selectivity is incomplete. A phase 1 clinical trial in healthy young men, published in The Journals of Gerontology, found that LGD-4033 suppressed the body’s own testosterone production in a dose-dependent way over just 21 days. At the highest dose tested (1.0 mg per day), both free testosterone and follicle-stimulating hormone dropped significantly. The drug also lowered HDL (“good”) cholesterol and triglyceride levels. In other words, it still affects hormonal systems beyond muscle tissue.
What the Clinical Trials Show
LGD-4033 has been studied in two main clinical settings. The first was a phase 1 safety trial in healthy men, which confirmed that the drug increases lean body mass at low doses while suppressing natural hormone levels. The second, more notable trial tested the compound (renamed VK5211 by its developer, Viking Therapeutics) in 108 patients recovering from hip fracture surgery.
In that phase 2 trial, patients received daily doses of 0.5 mg, 1.0 mg, or 2.0 mg for 12 weeks, compared to placebo. The results were striking for a frail population: patients on the highest dose gained more than six pounds of lean body mass while simultaneously losing fat mass. They also walked more than 20 meters farther in a six-minute walk test compared to placebo, suggesting a real functional benefit for mobility. No drug-related serious adverse events were reported, and markers like hemoglobin, red blood cell counts, and clotting factors stayed within normal ranges during the study period.
These results are promising for potential medical use, but they come from a controlled clinical environment with pharmaceutical-grade material. They don’t reflect what someone buying LGD-4033 online would experience.
Hormonal Suppression
One of the most important things to understand about LGD-4033 is that it suppresses your body’s natural testosterone production. Even at doses as low as 1.0 mg per day, the phase 1 trial showed significant drops in total testosterone, free testosterone, and sex hormone-binding globulin (SHBG) within three weeks. Higher doses caused greater suppression.
This means that after stopping LGD-4033, your hormonal system needs time to recover. How long that takes varies, and the clinical data on recovery timelines is limited. This suppression is the reason many users of SARMs pursue post-cycle therapy, borrowing protocols from the anabolic steroid world, though no such approach has been validated in clinical trials for SARMs specifically.
Cholesterol and Cardiovascular Effects
LGD-4033 lowers HDL cholesterol in a dose-dependent manner. HDL is the type that helps clear cholesterol from your arteries, so a drop in HDL is generally unfavorable for heart health. The phase 1 trial also noted changes in triglyceride levels. While these shifts may reverse after stopping the drug, repeated or prolonged use could compound cardiovascular risk, particularly in people who already have unfavorable lipid profiles.
Liver Injury
Case reports have documented severe liver damage linked to LGD-4033 use. One published case described a 32-year-old man who developed drug-induced liver injury after taking 10 mg of ligandrol daily for just two weeks. His liver enzyme levels spiked, and his total bilirubin (a marker of liver function) eventually reached 35 mg/dL, a dangerously high level that indicates the liver is struggling to process waste. The patient’s condition was classified as severe hepatotoxicity.
It’s worth noting that 10 mg is far higher than the doses used in clinical trials (which topped out at 2 mg). Products sold online often suggest doses in this range or higher, and there is no regulatory oversight ensuring that the product contains what the label claims.
Legal and Regulatory Status
LGD-4033 occupies a gray area that confuses a lot of people. It is not approved by the FDA as a drug or a dietary supplement. Companies cannot legally market it for human consumption in the United States. The FDA has issued multiple warning letters to companies selling SARMs, including ligandrol, and has pursued criminal charges against some distributors.
Despite this, LGD-4033 is widely available online, typically sold with a “for research purposes only” label. This labeling is a legal workaround, not a genuine restriction. The products are clearly marketed toward people who intend to take them. Because these products are unregulated, there is no guarantee of purity, dosage accuracy, or that the bottle even contains LGD-4033 at all. Independent lab analyses of SARMs sold online have repeatedly found mislabeled ingredients, contamination with other substances, or doses that don’t match the label.
Banned in All Organized Sports
The World Anti-Doping Agency (WADA) lists LGD-4033 by name as a prohibited substance under the category of “Other Anabolic Agents.” It is banned at all times, both in and out of competition. This applies to all athletes subject to WADA testing, including Olympic sports, NCAA athletics, and most professional leagues. Several athletes have received suspensions after testing positive for ligandrol, some claiming contaminated supplements as the source.
Because LGD-4033 and its metabolites can be detected in urine for an extended period, even trace contamination in a poorly manufactured supplement could trigger a positive test. This is a real risk for competitive athletes who use any products from companies that also handle SARMs.
Why People Use It Anyway
The appeal is straightforward. LGD-4033 is taken as a pill (not injected), it builds muscle at low doses, and it was designed to cause fewer androgenic side effects than steroids, like acne, hair loss, and prostate enlargement. For people looking to gain muscle or recover from injury, it appears to offer a simpler, milder alternative to traditional anabolic steroids.
The reality is more complicated. The drug still suppresses your natural hormones, alters your cholesterol, and carries a real risk of liver damage, especially at the doses commonly promoted online. The long-term effects are completely unknown because no study has followed users for more than 12 weeks. And the products available outside clinical trials are unregulated, meaning you cannot verify what you’re actually taking.