When it comes to oral "sports" substances, the liver is often the first thought: tablet steroids have long had a reputation for being hepatotoxic. Does this apply to ibutamoren? The editors analyzed what the clinical data say, how ibutamoren differs from alkylated steroids, and where the threat to the liver may actually come from.
Why the question arises about the liver
The liver is the main organ of metabolism of most oral substances. Everything that is absorbed from the intestine first enters the liver with the blood of the portal vein, where some of the molecules are converted by enzymes. Therefore, the issue of hepatotoxicity is natural for any tablet compound.
In sports pharmacology, this issue is exacerbated by experience with 17-alpha-alkylated anabolic steroids such as metandienone or oxandrolone. Their chemical modification, which allows them to survive the first passage through the liver, is associated with cholestasis, peliosis of the liver and tumors. These risks are detailed in a review by the Endocrine Society (Pope et al., 2014).
Ibutamoren does not belong to this class. It is not a steroid and does not have an alkylated steroid structure, so the mechanism by which pill steroids damage the liver does not apply to it.
At the same time, any substance can theoretically cause idiosyncratic drug-induced liver damage — an unpredictable reaction in individual people. Such reactions are rare and, as a rule, not detected in small studies.
What clinical studies have shown
In the older controlled trials discussed below, hepatotoxicity was not described as a characteristic adverse effect. The main adverse events reported by the authors were related to appetite, fluid retention, muscle pain, and carbohydrate metabolism.
In a two-year study by Nass et al. (2008), elderly people were monitored for a wide range of laboratory parameters. Among the changes noted by the author, glucose and insulin sensitivity, rather than liver enzymes, attracted the main attention.
At the same time, the scale of these data should be taken into account. The published trial population summarized here is in the hundreds, not the tens of thousands. Idiosyncratic liver damage often occurs with a frequency of one in thousands or tens of thousands, and is detected only after extensive use.
The trials discussed here did not identify liver toxicity as a common adverse effect, but this is not the whole literature. A July 2025 case report described elevated aminotransferases after two months of MK-677 use, with normalization after cessation. A single case does not establish incidence or a fully proven mechanism, but it rules out a blanket claim that no hepatic signal has been reported.
| A risk factor for the liver | Tableted 17α-alkylated steroids | Ibutamoren (pharmaceutical substance) | Product from an uncontrolled market |
|---|---|---|---|
| Structural hepatotoxicity | Well documented | No established steroid-like mechanism; reported liver injury exists | Depends on the actual composition |
| Idiosyncratic reactions | Possible | Cannot be excluded; limited clinical data | Possible |
| Impurities and substance substitution | Relevant for illegal drugs | Not the focus in controlled, characterized trial material | Main risk |
| Metabolic impact (insulin resistance) | Yes, through lipids | Yes | Yes |
Growth hormone, IGF-1 and the liver
The liver is not only a potential "victim" of ibutamoren, but also a participant in its action. It is in the liver under the influence of growth hormone that most of the circulating IGF-1 is synthesized. The increase in IGF-1 in the blood during ibutamoren reflects the hepatic response to a hormonal signal; it is not proof that the liver is healthy.
Growth hormone also affects fat metabolism in the liver. Growth hormone deficiency in adults is associated with more frequent nonalcoholic fatty liver disease, and replacement therapy in such patients can reduce liver fat, according to a number of studies. This is sometimes presented as an argument in favor of the "protective" action of ibutamoren.
However, we advise caution with this conclusion. Ibutamoren simultaneously increases appetite and reduces sensitivity to insulin. Namely, insulin resistance and excess caloric intake are the key drivers of fatty liver disease. The net effect on the liver may depend on diet, body weight, and baseline metabolic state.
Direct studies of the effect of ibutamoren on the fat content in the human liver, as far as the editors know, have not been conducted. So any claims about "treatment of fatty liver" with ibutamoren have no evidence base.
Real threat: product composition
Unknown product composition is an important additional risk. Online “research chemical” labeling does not guarantee identity, dose or pharmaceutical quality. It is not possible to rank this above intrinsic hepatic risk with confidence or assume every injury must come from contamination.
A study by Van Wagoner et al (2017) published in JAMA analyzed products marketed online as SARMs. A significant part of them did not correspond to the label: they contained other substances, a different amount of the active substance or did not contain it at all. Among the detected compounds were substances from other classes, in particular ibutamoren and the PPAR-δ agonist GW501516.
For the liver, this is important because SARMs and hidden oral steroids have been associated with drug-induced liver injury reported in the clinical literature. A person who believes he is only taking ibutamoren may actually be receiving a hepatotoxic substance.
A separate factor is the simultaneous use of several substances, alcohol, high doses of paracetamol or herbal "detox" supplements. Some herbal supplements are known to cause liver damage on their own, and combinations make it difficult to find the culprit.
- Product of unknown origin may contain SARMs or steroids.
- The actual dose may differ from the stated one.
- Combination with alcohol and other substances increases the load on the liver.
How to control the condition of the liver
Basic assessment of liver status includes alanine aminotransferase (ALT), aspartate aminotransferase (AST), total and direct bilirubin, alkaline phosphatase, and gamma-glutamyltransferase. These indicators help distinguish damage to liver cells from impaired bile flow.
An important nuance for people who train: intense physical activity can increase AST and ALT due to the release of enzymes from the muscles. Tell the clinician about recent exercise. A rest period may help interpret nonurgent repeat tests, but symptoms of liver injury require prompt assessment.
The American College of Gastroenterology's clinical guideline on drug-induced liver injury (Chalasani et al., 2021) emphasizes that a key step in suspected injury is discontinuing the suspected substance and taking a thorough history, including supplements and unlabeled products.
Alarming symptoms that require immediate medical attention: jaundice of the skin or sclera, dark urine, light-colored feces, itching, pain in the right hypochondrium, pronounced weakness and nausea.
Editorial conclusions
Ibutamoren is not an alkylated steroid. Older trials did not show the characteristic cholestatic pattern associated with oral anabolic steroids, but a 2025 liver-injury case report means that absence of all clinical hepatic concern would be an inaccurate claim.
However, there is insufficient data to rule out rare reactions, and the substance's metabolic effects—insulin resistance and increased appetite—could theoretically contribute to fatty liver disease.
Uncertain product identity and co-exposures complicate both safety and attribution. They add to the limited evidence rather than demonstrate that the molecule itself is harmless.
The editors also recommend materials on counterfeit ibutamoren and laboratory tests of products, on side effects of the substance and on liver tests for people who train.
References
- Nass R, Pezzoli SS, Oliveri MC, et al. Effects of an oral ghrelin mimetic on body composition and clinical outcomes in healthy older adults: a randomized trial. Ann Intern Med. 2008;149(9):601–611.
- Pope HG Jr, Wood RI, Rogol A, et al. Adverse health consequences of performance-enhancing drugs: an Endocrine Society scientific statement. Endocr Rev. 2014;35(3):341–375.
- 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.
- Chalasani NP, Maddur H, Russo MW, et al. ACG clinical guideline: diagnosis and management of idiosyncratic drug-induced liver injury. Am J Gastroenterol. 2021;116(5):878–898.
- LiverTox: Clinical and Research Information on Drug-Induced Liver Injury. Bethesda (MD): National Institute of Diabetes and Digestive and Kidney Diseases; 2012–.
