Clenbuterol has a different name

ClenbuterolDrug groupsAntiasthmaticsBeta2 sympathomimeticsLABAClenbuterol is an active ingredient from the group of β2-Sympathomimetics for oral or inhalation treatment of asthma and chronic bronchitis. Due to its anabolic effect, Clenbuterol is misused as a doping agent in competitive sports and as an illegal growth-promoting agent in animal fattening. Possible adverse effects include tremors, headaches, restlessness, nausea, heartburn, dizziness, muscle pain, muscle cramps, and cardiovascular disorders. Overdosing is potentially dangerous. Anyone who consumes contaminated meat risks a false positive doping control.

synonymous: Clenbuterolum, Clenbuteroli hydrochloridumPhEur, Clenbuterol hydrochloride


In Switzerland, Clenbuterol is not sold as a medicinal product for human use, but exclusively as a veterinary medicinal product for the treatment of respiratory diseases (e.g. Ventipulmin® ad us vet). It is only available with a doctor's prescription. In other countries, Clenbuterol is on the market in the form of tablets and drops (Spiropent®).

Structure and properties

Clenbuterol (C.12H18Cl2N2O, Mr = 277.2 g / mol) is a phenylethylamine derivative and a racemate. It has a similar structure to other beta2-sympathomimetics, for example salbutamol (Ventolin®, generics). In pharmaceuticals it is present as clenbuterol hydrochloride, a white, crystalline powder that is soluble in water.


Clenbuterol (ATC R03AC14) has sympathomimetic, bronchodilator and anti-inflammatory properties. It is anabolic (promotes growth), promotes insulin release, builds muscle and breaks down fat. In low doses it stimulates the adrenergic β2-Receptors of the bronchial muscles. It is less selective in high doses. When taken orally, the effects occur within about 5-20 minutes and last for up to 14 hours. The terminal half-life is given as 34 hours.

Mechanism of action of the beta2 sympathomimetics, click to enlarge. Illustration © PharmaWiki


For the treatment of obstructive airways diseases, e.g. asthma and chronic obstructive bronchitis. For this purpose, Clenbuterol is approved as a veterinary medicinal product in Switzerland. Medicinal products for human use are not on the market.

Abuse as a doping agent

Due to its anabolic effects, Clenbuterol can be misused as a doping agent and anabolic steroid in competitive sports and bodybuilding. It is on the doping list and is forbidden before, during and after the competition. For example, professional cyclist Alberto Contador was convicted of clenbuterol abuse by the International Court of Justice in 2012 and had to surrender his victory at the Tour de France in 2010.

Clenbuterol is used in animal fattening as an illegal growth-promoting agent because it promotes the development of lean meat and breaks down fat at the same time. The consumption of contaminated meat can lead to false positive doping results, as is probably the case with table tennis professional Dimitrij Ovtcharov. It is not undisputed whether Clenbuterol is actually suitable as a doping agent in humans. Improper use is not recommended in any case.


According to the medicinal product information. Clenbuterol can be inhaled as a solution or taken orally.


The complete precautionary measures can be found in the medicinal product information sheet.


Numerous drug interactions are possible. They can be found in the specialist information for medicinal products. Clenbuterol is largely excreted unchanged in the urine.

unwanted effects

As with other beta2-sympathomimetics, the most common undesirable effects include tremors, headache, restlessness, nausea, heartburn, dizziness, muscle pain, muscle cramps, nervousness, allergic reactions and urinary retention. Cardiovascular disorders such as rapid pulse, cardiac arrhythmias, chest pain, extrasystoles and ischemia are possible. Hypokalaemia, hyperglycaemia, increased insulin, and kidney disorders are rare. Such side effects are also possible when consuming clenbuterol contaminated meat. This can also lead to dangerous overdoses with a rapid heartbeat, cardiac arrhythmias, low blood pressure, shock and cramps.

see also

Beta2 sympathomimetics

  • Pharmaceutical product information (Spiropent® tablets, drops, Ventipulmin® ad us vet.)
  • Beckett A.H. Clenbuterol and sport. Lancet, 1992, 340 (8828), 1165 Pubmed
  • Chan T.Y. Food-borne clenbuterol may have potential for cardiovascular effects with chronic exposure (commentary). J Toxicol Clin Toxicol. 2001, 39 (4), 345-8 Pubmed
  • European Pharmacopoeia PhEur
  • Kearns C.F., McKeever K.H. Clenbuterol and the horse revisited. Vet J, 2009, 182 (3), 384-91 Pubmed
  • Media reports
  • Parr M.K., Koehler K., Geyer H., Guddat S., Schänzer W. Clenbuterol marketed as dietary supplement. Biomed Chromatogr, 2008, 22 (3), 298-300 Pubmed
  • Perry H. Clenbuterol: a medal in tablet form? Br J Sports Med, 1993, 27 (2), 141 Pubmed
  • Prather I.D., Brown D.E., North P., Wilson J.R. Clenbuterol: a substitute for anabolic steroids? Med Sci Sports Exerc, 1995, 27 (8), 1118-21 Pubmed
  • Prezelj A., Obreza A., Pecar S. Abuse of clenbuterol and its detection. Curr Med Chem, 2003, 10 (4), 281-90 Pubmed
  • Spann C., Winter M.E. Effect of clenbuterol on athletic performance. Ann Pharmacother, 1995, 29 (1), 75-7 Pubmed
  • swell
  • Reynolds J. (Ed.) Martindale. The Extra Pharmacopoeia. London: The Pharmaceutical Press, 1989
  • Swissmedic
  • Compendium of veterinary medicinal products

Conflicts of Interest: None / Independent. The author has no relationships with the manufacturers and is not involved in the sale of the products mentioned.

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