Clenbuterol, or "clen," is a veterinary drug originally used to treat respiratory diseases in horses. It has since been used to add bulk to livestock, though the United States has banned and monitors such use. According to the Drug Enforcement Administration (DEA), clenbuterol is currently being used illicitly as a muscle-enhancing, fat-reducing agent among athletes, bodybuilders and others seeking a trim, muscular physique 2. Clenbuterol poses numerous side effects, some of which are life-threatening.
If you are experiencing serious medical symptoms, seek emergency treatment immediately.
Psychiatric Side Effects
Clenbuterol has been shown to produce serious psychiatric side effects in women. According to research published in 2000 in "Psychotherapy and Psychosomatics," 33 percent of female athletes studied reported abuse of clenbuterol currently or in the past, often in addition to other performance-enhancing drugs. Of these women, numerous described addiction to clenbuterol. Fifty-six percent of the women who used clenbuterol reported hypomania, which is an elevated or irritable mood, and 40 percent reported depression during withdrawal from the drug. Researchers indicate that female athletes who use or previously used clenbuterol often have history of psychological problems, such as eating disorders.
- Clenbuterol has been shown to produce serious psychiatric side effects in women.
- Fifty-six percent of the women who used clenbuterol reported hypomania, which is an elevated or irritable mood, and 40 percent reported depression during withdrawal from the drug.
Neurological and Cardiovascular Effects
Clenbuterol Side Effects
Clenbuterol is an adrenergic bronchodilator, meaning it works to open the bronchial tubes. Like other adrenergic bronchodilators, the DEA suggests that clenbuterol can produce serious, adverse neurological and cardiovascular effects. Women and men may experience rapid or irregular heartbeat, muscle spasms and general nervousness. Since clenbuterol is easily absorbed and stays in the body for up to 39 hours after ingestion, these effects may last for one to two days. Women with a family or personal history of heart problems, kidney disease or heart defects may reap the most serious cardiovascular effects from clenbuterol. Severe cardiovascular disturbances associated with clenbuterol may result in death.
- Clenbuterol is an adrenergic bronchodilator, meaning it works to open the bronchial tubes.
- Women with a family or personal history of heart problems, kidney disease or heart defects may reap the most serious cardiovascular effects from clenbuterol.
Clenbuterol continues to be used illegally as a growth-inducer in livestock in various parts of the world. According to the DEA, numerous outbreaks of flulike symptoms in people who consumed meat containing clenbuterol residue occurred in Spain, Italy, Portugal, China and France. Symptoms such as dizziness, nausea, vomiting, fever and chills developed within three hours after eating the clenbuterol-affected food and persisted for two to six days. While the United States and Europe monitor tissue and urine samples of livestock to prevent such outbreaks, similar symptoms may occur in women, men and children who abuse or consume clenbuterol.
- Clenbuterol continues to be used illegally as a growth-inducer in livestock in various parts of the world.
- While the United States and Europe monitor tissue and urine samples of livestock to prevent such outbreaks, similar symptoms may occur in women, men and children who abuse or consume clenbuterol.
Clenbuterol Side Effects
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- U.S. Department of Justice, Drug Enforcement Administration, Diversion Control Division. Clenbuterol. Updated July 2019.
- Drake SD, Hansen LE, Harris C, et al. Effects of clenbuterol on horses. Comp Exerc Physiol. 2013;9(3-4):181-187. doi:10.3920/CEP13022
- Medellín-Martínez MF, Luna-Zavala I, Martínez-Delgado M, Pérez-Urizar JT, Ramírez-Telles JA, Patiño-Rodríguez O. Sensitive Assay of Clenbuterol Residues in Beef by Ultra-High Performance Liquid Chromatography Coupled with Mass Spectrometry (UPLC-MS/MS) and Solid-Phase Extraction. Food Anal Methods. 2018;11:2561-2568. doi:10.1007/s12161-018-1222-1
- Jessen S, Solheim SA, Jacobson GA, et al. Beta2-adrenergic agonist clenbuterol increases energy expenditure and fat oxidation, and induces mTOR phosphorylation in skeletal muscle of young healthy men. Drug Test Anal. 2020;12(5):610-618. doi:10.1002/dta.2755
- Kim HK, Della-Fera MA, Hausman DB, Baile CA. Effect of clenbuterol on apoptosis, adipogenesis, and lipolysis in adipocytes. J Physiol Biochem. 2010;66(3):197-203. doi:10.1007/s13105-010-0024-8
- Santos RP, Pereira A, Guedes H, Lourenço C, Azevedo J, Pinto P. Anabolic drugs and myocardial infarction - A clinical case report. Arq Bras Cardiol. 2015;105(3):316-319. doi:10.5935/abc.20150111
August McLaughlin is a certified nutritionist and health writer with more than nine years of professional experience. Her work has been featured in various magazines such as "Healthy Aging," "CitySmart," "IAmThatGirl" and "ULM." She holds specializations in eating disorders, healthy weight management and sports nutrition. She is currently completing her second cookbook and Weight Limit—a series of body image/nutrition-related PSAs.