Ligandrol or Ostarine: What Is the Difference

Ligandrol (LGD-4033, later VK5211) and ostarine (enobosarm, MK-2866) are two SARMs for which published randomized studies in humans exist. This makes comparing them more meaningful than for most substances of this class. The editorial team examines how they differ in chemistry, pharmacokinetics, clinical data, and risks.

Two SARMs with different histories

Ostarine was created by GTx Inc.; it went the path from preclinical studies to phase III in patients with cancer cachexia. Ligandrol was developed by Ligand Pharmaceuticals, later the rights to the molecule passed to Viking Therapeutics, where it received the code VK5211.

Both substances were conceived as agents against loss of muscle mass: ostarine - in cancer and sarcopenia, ligandrol - in age-related muscle loss and after hip fractures. According to the developer's reports, VK5211 was studied in phase II in patients recovering after a femoral neck fracture.

Neither drug received registration as a medicine. However, they are better studied than most other SARMs, which allows comparing them on the basis of real data, not just marketing.

At the same time, it is important to remember: the published studies were short, had a small number of participants, and were conducted under controlled conditions. Their results cannot be transferred to long-term independent use.

Chemistry and pharmacokinetics

Both substances are non-steroidal, but belong to different chemical classes. Ostarine is an arylpropionamide, derived from early molecules created on the basis of non-steroidal antiandrogens. Ligandrol has a different structure containing a pyrrolidine ring and a benzonitrile fragment.

In a phase I study (Basaria et al., 2013) ligandrol had a long half-life, so with each day of intake its blood concentration rose until a steady state was reached. This is important from a safety standpoint: the exposure accumulates gradually.

Both substances are active when taken orally and are full or partial agonists of the androgen receptor in muscle tissue. Tissue selectivity, according to a review by Narayanan and colleagues (2018), is relative, not absolute.

What the clinical trials showed

In a randomized placebo-controlled study by Basaria and colleagues (2013), 76 healthy young men received ligandrol at doses of 0.1, 0.3, or 1 mg per day or placebo for 21 days. Lean body mass increased in a dose-dependent manner, most of all in the 1 mg group.

In the same study a dose-dependent decrease in HDL, total testosterone, and sex-hormone-binding globulin (SHBG) was recorded. After discontinuation the indicators returned to baseline values.

For ostarine the key study is the phase II study (Dalton et al., 2011): 120 elderly men and postmenopausal women, 12 weeks of intake. In the 3 mg per day group, lean body mass and a physical function measure improved compared with placebo.

There are no direct comparative studies of ligandrol and ostarine. Because of the different populations (young men versus elderly people), different durations, and assessment methods, it is impossible to correctly compare them as to "who is stronger."

Shared and distinct risks

For both substances, changes in the lipid profile, primarily a decrease in HDL, and suppression of one's own hormones were observed in the published studies. A review by Solomon and colleagues (2019) describes these effects as characteristic of the SARM class.

• Hormonal axis:both SARMs lower testosterone; in the ligandrol study the decrease was observed within as little as three weeks.
• Lipids:a decrease in HDL is the most consistent finding.
• Liver:cases of drug-induced liver injury have been described with the use of products containing ligandrol, ostarine, and other SARMs (Flores et al., 2020).
• Unknown:the consequences of long-term use, interactions with other substances.

The long half-life of ligandrol means that after discontinuation the substance and its effects persist longer than for substances with a short half-life. This can matter both for safety and for doping control.

A separate risk is product quality. According to Van Wagoner and colleagues (2017), products sold as SARMs often contained the wrong substance or the wrong amount than indicated on the label.

In clinical trials, participants underwent careful selection and monitoring. In the real world this is absent, so the frequency of side effects may be higher.

Doping control and legal status

Ligandrol and ostarine belong to section S1.2 "Other anabolic agents" of the WADA Prohibited List and are prohibited at all times. Anti-doping laboratories have methods for detecting both substances and their metabolites.

Ostarine is one of the substances most often detected in anti-doping samples among SARMs. Some of these cases are associated with contaminated supplements, which underscores the importance of certified products for athletes.

In many countries SARMs are not permitted dietary supplements. The FDA has repeatedly warned companies that sold them under the guise of supplements and informed consumers about the risks.

For athletes, the principle of strict liability applies: the presence of a prohibited substance in a sample is a violation regardless of how it got there.

Editorial conclusions

Ligandrol and ostarine are non-steroidal androgen receptor modulators of different chemical structure, each with its own clinical history. Ligandrol was studied in phase I in young men and in phase II after hip fractures, ostarine up to phase III in oncology patients.

Both lower HDL and one's own testosterone, are associated with cases of liver injury, and are banned by WADA.

Short controlled studies are not enough to speak of the safety of long-term use.

The editorial team also recommends reading "Ligandrol vs Ostarine: what to choose and for whom," the article "Ostarine or RAD-140: what is the difference," and a review of the lipid panel for athletes.

References

1. 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.
2. Dalton JT, Barnette KG, Bohl CE, et al. The selective androgen receptor modulator GTx-024 (enobosarm) improves lean body mass and physical function in healthy elderly men and postmenopausal women: results of a double-blind, placebo-controlled phase II trial. J Cachexia Sarcopenia Muscle. 2011;2(3):153–161.
3. Narayanan R, Coss CC, Dalton JT. Development of selective androgen receptor modulators (SARMs). Mol Cell Endocrinol. 2018;465:134–142.
4. Solomon ZJ, Mirabal JR, Mazur DJ, et al. Selective androgen receptor modulators: current knowledge and clinical applications. Sex Med Rev. 2019;7(1):84–94.
5. 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.
6. Flores JE, Chitturi S, Walker S. Drug-induced liver injury by selective androgenic receptor modulators. Hepatol Commun. 2020;4(3):450–452.
7. World Anti-Doping Agency. International Standard: Prohibited List. Montreal: WADA; 2025.