Ligandrol, code name LGD-4033 and later VK5211, is an experimental oral drug from the class called selective androgen receptor modulators (SARMs). Ligand Pharmaceuticals developed it to build muscle and bone while sparing tissues such as the prostate. Viking Therapeutics later tested it in older adults recovering from hip fracture.
It has never been approved as a medicine anywhere we could find. Only two controlled human trials have published or posted results: a 3-week safety study in 76 healthy young men, and a 12-week phase 2 trial in 108 older adults after hip fracture. Ligandrol is nonetheless widely sold online as a “research chemical” or supplement, and the FDA has issued warning letters to sellers.
This page summarizes what the clinical trials, case reports and regulators report. It is for education only and is not medical advice.
| Property | Detail |
|---|---|
| Drug class | Nonsteroidal selective androgen receptor modulator (SARM) |
| Developer / code names | Ligand Pharmaceuticals (LGD-4033); licensed to Viking Therapeutics as VK5211 |
| Route | Oral |
| Doses studied in trials | 0.1, 0.3 and 1.0 mg/day for 21 days (healthy men); 0.5, 1.0 and 2.0 mg/day for 12 weeks (hip fracture) |
| Half-life | 24–36 h in healthy men |
| Receptor binding | Binds the androgen receptor with high affinity (Ki ≈ 1 nM) |
| US status | Not FDA approved; FDA says it cannot be sold as a dietary supplement |
| WADA status | Prohibited at all times (S1.2, other anabolic agents), named on the 2026 List |
What it is
LGD-4033 is a small synthetic molecule, not a steroid. Its chemical name is 4-[(2R)-2-[(1R)-2,2,2-trifluoro-1-hydroxyethyl]pyrrolidin-1-yl]-2-(trifluoromethyl)benzonitrile, formula C₁₄H₁₂F₆N₂O, molecular weight 338.25 g/mol (PubChem).
Like testosterone, it activates the androgen receptor. The idea behind SARMs is “tissue selectivity”: strong action in muscle and bone with less effect on the prostate, skin and other androgen-sensitive tissues. In the first published human trial, the authors noted that LGD-4033 binds the receptor with a Ki (a measure of binding strength) of about 1 nM. They also reported that in animal models it had anabolic effects on muscle and bone with selectivity for muscle over prostate (Basaria et al., J Gerontol A 2013). Those selectivity data come from animals; they have not been shown to hold in people over the long term.
Because it is not a steroid, LGD-4033 is not converted to estradiol or DHT the way testosterone is. That does not mean it lacks hormonal side effects. As shown below, it suppressed the body’s own testosterone and lowered HDL cholesterol even at 1 mg/day.
Ligand began phase 1 trials of LGD-4033 capsules in 2009. Viking Therapeutics later started a phase 2 trial under the name VK5211, as summarized in an FDA warning letter (FDA warning letter, 2017).
Pharmacokinetics
The only published human pharmacokinetic data come from the 21-day trial in healthy men (Basaria et al., J Gerontol A 2013):
| Parameter | Finding |
|---|---|
| Elimination half-life | 24–36 h |
| Dose relationship | Linear; blood levels rose in proportion to dose |
| Accumulation | Levels on day 21 were nearly 3× those on day 1 with daily dosing |
| Mean AUC on day 21 | 19, 85 and 238 ng·24 h/mL at 0.1, 0.3 and 1.0 mg |
The long half-life means the drug builds up over the first days of daily use. An earlier single ascending-dose phase 1 study had tested single doses up to 22 mg, according to the same paper; its full results have not been published.
The body breaks LGD-4033 down into hydroxylated metabolites, which are excreted in urine partly bound to glucuronic acid. In a human excretion study, anti-doping scientists followed one volunteer’s urine for almost 21 days and identified dihydroxylated metabolites as the preferred markers for testing (Fragkaki et al., Drug Test Anal 2018).
Regulatory status
- Not an approved drug. No regulator has approved LGD-4033 for any use. A 2023 review notes that no SARM has been approved by the FDA or the European Medicines Agency (Vignali et al., J Xenobiot 2023).
- Not a legal dietary supplement in the US. In 2017 warning letters, FDA stated that products containing LGD-4033 do not meet the legal definition of a dietary supplement, because the compound was authorized for investigation as a new drug before it was ever marketed as a supplement or food. The same letters warned that “life threatening reactions, including liver toxicity” have occurred with SARM products, and that SARMs may raise the risk of heart attack and stroke (FDA warning letter, 2017).
- Ongoing FDA enforcement. FDA sent further warning letters in December 2025 to websites selling LGD-4033 under the name Ligandrol, alongside RAD-140, S-4 and YK-11 (FDA warning letter, 2025).
- Banned in sport. The 2026 WADA Prohibited List names “LGD-4033 (ligandrol)” under S1.2, other anabolic agents, which are prohibited both in and out of competition (WADA 2026 List).
What the research shows
Healthy young men: 21-day dose-ranging trial
In a randomized, double-blind, placebo-controlled trial, 76 healthy men aged 21–50 took placebo or LGD-4033 at 0.1, 0.3 or 1.0 mg daily for 21 days; 68 completed the study (Basaria et al., J Gerontol A 2013). The men did not follow a training program.
| Outcome | Result |
|---|---|
| Lean body mass | Rose with dose (p for trend = 0.04); +1.21 kg at 1.0 mg (p = 0.047 vs placebo) |
| Fat mass | No significant change |
| Appendicular muscle mass | −0.2, +0.04, +0.47 and +0.37 kg (placebo, 0.1, 0.3, 1.0 mg); not significant |
| Leg press strength | +68.3 N at 1.0 mg; not significantly different from placebo |
| Stair-climbing speed and power | Trend toward improvement; not significant |
| Muscle protein synthesis (0.3 mg) | No difference from placebo |
The trial was short and small, and it was designed mainly to test safety. It showed that LGD-4033 has measurable anabolic activity at 1 mg/day. It did not show gains in strength or physical function.
Older adults after hip fracture: 12-week phase 2 trial (VK5211)
Viking Therapeutics ran a randomized, double-blind, placebo-controlled trial in 108 men and women aged 65 and older, enrolled 3–7 weeks after a hip fracture (ClinicalTrials.gov NCT02578095). Participants took placebo or VK5211 at 0.5, 1.0 or 2.0 mg once daily for 12 weeks. The primary endpoint was the change in lean body mass (excluding the head) measured by DXA scan.
| Dose | Analyzed n | Placebo-adjusted change in lean body mass (95% CI) | p vs placebo |
|---|---|---|---|
| Placebo | 20 | — | — |
| 0.5 mg/day | 27 | +4.75% (1.70–7.80) | 0.0032 |
| 1.0 mg/day | 17 | +7.15% (3.76–10.54) | under 0.0001 |
| 2.0 mg/day | 15 | +9.08% (5.55–12.60) | under 0.0001 |
Lean mass gains rose with dose. Several caveats apply:
- These results were posted to the trial registry. We did not find a peer-reviewed publication of the full trial.
- Only 75 of 108 participants completed the study, and the efficacy analysis included 79.
- The registry reports the lean mass endpoint only. It does not show whether walking, strength or recovery from the fracture improved.
ClinicalTrials.gov lists no later-phase trial of VK5211 or LGD-4033.
Use outside medicine
Nearly all real-world human data on ligandrol come from people using it without medical supervision, at doses well above those tested in trials. These are case reports, which cannot establish how common an effect is.
One published case followed a 25-year-old man who took 10 mg/day LGD-4033 together with 15 mg/day of the growth hormone secretagogue ibutamoren (MK-677) for 5 weeks (Cardaci et al., Exp Physiol 2022):
| Measure | Change on the drugs |
|---|---|
| Total lean mass | +3.1% |
| Total fat mass | +15.4% |
| Bone mineral density | −2.1% |
| HDL cholesterol | −36.4% |
| LDL cholesterol | +40.0% |
| ALT (liver enzyme) | +205% |
| Total testosterone | −62.3% |
| Free testosterone | −85.7% |
Most values returned to pre-use levels after he stopped. This is a single person taking two drugs at once, so the effects cannot be assigned to LGD-4033 alone.
Side effects and risks
Suppression of natural testosterone
In the 21-day trial, LGD-4033 caused dose-dependent falls in total testosterone and sex hormone-binding globulin (SHBG). Free testosterone and FSH, one of the pituitary hormones that drive the testes, fell significantly at the 1.0 mg dose. Hormone levels returned to baseline by day 56, about five weeks after stopping (Basaria et al., J Gerontol A 2013).
“SARMs don’t suppress.” This claim is common online, but it is not what the trial found. Even 1 mg/day for three weeks lowered testosterone and FSH. The case report above, at 10 mg/day with MK-677, found total testosterone 62% lower. No study has measured hormone recovery after longer or higher-dose use.
Lipids
HDL (“good”) cholesterol fell at doses of 0.3 mg and above. Triglycerides also fell, while total and LDL cholesterol did not change significantly. All returned to baseline after stopping (Basaria et al., J Gerontol A 2013):
| Daily dose | Mean HDL at baseline | Change at day 21 |
|---|---|---|
| Placebo | 52.5 mg/dL | −1.7 mg/dL |
| 0.1 mg | 56.1 mg/dL | −1.0 mg/dL |
| 0.3 mg | 50.3 mg/dL | −10.4 mg/dL |
| 1.0 mg | 49.2 mg/dL | −19.4 mg/dL |
At 1.0 mg, HDL fell by about 39% in three weeks. The authors noted that this pattern is typical of oral androgens and that its long-term cardiovascular meaning is unknown.
Liver injury
In the 21-day trial, liver enzymes (AST and ALT) did not change significantly at any dose. In the hip fracture trial, “hepatic enzyme increased” was recorded in 1 of 28 placebo patients and in 1 of 29, 1 of 26 and 4 of 25 patients on 0.5, 1.0 and 2.0 mg (ClinicalTrials.gov NCT02578095).
Outside trials, several case reports describe serious liver injury after ligandrol use:
- A 32-year-old man reported taking 10 mg daily for about 2 weeks. He developed jaundice, itching and 40 lb of weight loss, with total bilirubin reaching 35.0 mg/dL. Liver biopsy showed cholestatic hepatitis (injury that blocks bile flow) with mild fibrosis (Barbara et al., ACG Case Rep J 2020).
- A 37-year-old man had painless jaundice with bilirubin 30 times the upper limit of normal; biopsy showed cholestasis with loss of bile ducts and periportal fibrosis (Wallstab et al., Z Gastroenterol 2023).
- A 52-year-old man developed jaundice, itching and weight loss after three months of high-dose LGD-4033 (Labban et al., Cureus 2024).
- Two young men developed cholestatic liver injury after using ligandrol and/or ostarine followed by other drugs; both recovered after about 3 months (Koller et al., World J Clin Cases 2021).
- A 52-year-old man developed liver injury after products containing RAD-140 and LGD-4033; his liver enzymes normalized about 3 months after stopping (Barbara et al., ACG Case Rep J 2020).
A review of SARM liver cases describes a typical pattern: slow onset of jaundice with very high bilirubin but only mild enzyme rises, resembling the bland cholestasis seen with anabolic steroids. Most patients improve after stopping, and no specific treatment exists (Mohideen et al., J Clin Transl Hepatol 2023). In an Australian series of 23 liver injury cases linked to anabolic steroids, SARMs and bodybuilding supplements, median time to normal liver tests was 175 days, and one patient needed a liver transplant (Nash et al., Aliment Pharmacol Ther 2024).
Case reports cannot show how often this happens. Products were often not tested, and many patients took more than one substance.
Other reported harms
A systematic review of SARM safety in healthy adults (33 studies, 1,447 people exposed to a SARM, all compounds combined) found 15 case reports of drug-induced liver injury, one Achilles tendon rupture and one case of rhabdomyolysis (muscle breakdown). Elevated ALT was common in clinical trials, at a mean of 7.1% of SARM-exposed participants (Vignali et al., J Xenobiot 2023). These figures are for SARMs as a class, not LGD-4033 alone.
The long-term effects of LGD-4033 on the heart, fertility, prostate and bone are unknown. No trial has lasted longer than 12 weeks.
Who should not use it
There is no approved use and no labeled contraindication list. The healthy-men trial excluded people with active disease, raised PSA, abnormal liver tests or low HDL. Because of the liver case reports and hormone effects, people with liver disease, those trying to conceive, and anyone subject to drug testing face the clearest risks.
Quality and contamination
Products sold as ligandrol are unregulated. In a JAMA study, researchers bought 44 products marketed as SARMs online and analyzed them with WADA-approved methods (Van Wagoner et al., JAMA 2017):
| Finding | Products |
|---|---|
| Contained 1 or more SARMs (ostarine, LGD-4033 or andarine) | 23 of 44 (52%) |
| Contained another unapproved drug (e.g. ibutamoren, GW501516, SR9009) | 17 of 44 (39%) |
| Contained substances not listed on the label | 11 of 44 (25%) |
| No active compound detected | 4 of 44 (9%) |
| Amount matched the label | 18 of 44 (41%) |
A buyer of “ligandrol” therefore cannot be sure what compound, or how much, is in the product.
Legal status and use in sport
LGD-4033 is prohibited at all times under the WADA Code. Anti-doping laboratories test urine for its long-term metabolites. In one documented case, a female athlete’s positive test at very low levels was traced, using hair analysis, to contact with her husband, who was taking ligandrol; the Court of Arbitration for Sport lifted her provisional ban (Kintz and Gheddar, J Anal Toxicol 2025).
Key takeaways
- An unapproved investigational drug. LGD-4033 (VK5211) was tested in only two controlled trials, and no regulator has approved it. FDA says it cannot legally be sold as a dietary supplement.
- Lean mass rises at low doses. About 1.2 kg in 3 weeks at 1 mg/day in healthy men, and up to 9% placebo-adjusted in older adults after hip fracture at 2 mg/day. Strength and function gains were not shown.
- It does suppress testosterone. Even 1 mg/day for 3 weeks lowered testosterone and FSH and cut HDL by about 19 mg/dL, all reversible in the short trial.
- Liver injury is documented. Multiple case reports describe severe cholestatic liver injury after use, including one at 10 mg/day (ten times the highest dose in the healthy-men trial), with recovery often taking months.
- Products are unreliable. In a JAMA analysis, only about half of online “SARM” products contained a SARM, and only 41% matched their label.
- Banned in sport. WADA prohibits LGD-4033 at all times.
Sources
- Basaria S, Collins L, Dillon EL, et al. The safety, pharmacokinetics, and effects of LGD-4033, a novel nonsteroidal oral, selective androgen receptor modulator, in healthy young men. J Gerontol A Biol Sci Med Sci. 2013;68(1):87–95. PubMed.
- Viking Therapeutics. A phase II, randomized, double-blind, parallel group, placebo-controlled, multi-center study to explore the efficacy, safety and tolerability of VK5211 in subjects with acute hip fracture. NCT02578095. Results posted. ClinicalTrials.gov.
- National Center for Biotechnology Information. LGD-4033, PubChem CID 44137686. PubChem.
- Food and Drug Administration. Warning letter to Infantry Labs LLC, MARCS-CMS 535333. October 23, 2017. FDA.
- Food and Drug Administration. Warning letter to Titan SARMs LLC, MARCS-CMS 719645. December 12, 2025. FDA.
- World Anti-Doping Agency. The 2026 Prohibited List, valid January 1, 2026. WADA.
- Fragkaki AG, Sakellariou P, Kiousi P, et al. Human in vivo metabolism study of LGD-4033. Drug Test Anal. 2018;10(11-12):1635–1645. PubMed.
- Cardaci TD, Machek SB, Wilburn DT, et al. LGD-4033 and MK-677 use impacts body composition, circulating biomarkers, and skeletal muscle androgenic hormone and receptor content: a case report. Exp Physiol. 2022;107(12):1467–1476. PubMed.
- Barbara M, Dhingra S, Mindikoglu AL. Ligandrol (LGD-4033)-induced liver injury. ACG Case Rep J. 2020;7(6):e00370. PubMed.
- Barbara M, Dhingra S, Mindikoglu AL. Drug-induced liver injury associated with Alpha Bolic (RAD-140) and Alpha Elite (RAD-140 and LGD-4033). ACG Case Rep J. 2020;7(6):e00409. PubMed.
- Wallstab F, Jechorek D, Keitel-Anselmino V, Arnim UV. Ligandrol-induced liver injury: case report [in German]. Z Gastroenterol. 2023;61(5):522–525. PubMed.
- Labban H, Kwait B, Paracha A, et al. LGD-4033 and a case of drug-induced liver injury: exploring the clinical implications of off-label selective androgen receptor modulator use in healthy adults. Cureus. 2024;16(9):e69601. PubMed.
- Koller T, Vrbova P, Meciarova I, et al. Liver injury associated with the use of selective androgen receptor modulators and post-cycle therapy: two case reports and literature review. World J Clin Cases. 2021;9(16):4062–4071. PubMed.
- Mohideen H, Hussain H, Dahiya DS, Wehbe H. Selective androgen receptor modulators: an emerging liver toxin. J Clin Transl Hepatol. 2023;11(1):188–196. PubMed.
- Nash E, Nicoll A, Batt N, et al. Drug-induced liver injury from selective androgen receptor modulators, anabolic-androgenic steroids and bodybuilding supplements in Australia. Aliment Pharmacol Ther. 2024;59(8):953–961. PubMed.
- Vignali JD, Pak KC, Beverley HR, et al. Systematic review of safety of selective androgen receptor modulators in healthy adults: implications for recreational users. J Xenobiot. 2023;13(2):218–236. PubMed.
- Van Wagoner RM, Eichner A, Bhasin S, et al. Chemical composition and labeling of substances marketed as selective androgen receptor modulators and sold via the internet. JAMA. 2017;318(20):2004–2010. PubMed.
- Kintz P, Gheddar L. Drug transfer during intimate moments can produce an adverse analytical finding during a doping control: a case report with ligandrol. J Anal Toxicol. 2025;49(8):615–619. PubMed.