Clenbuterol is a prescription drug for sufferers of breathing disorders as a decongestant and bronchodilator. It's most commonly available in salt form as Clenbuterol Hydrochloride, and people with chronic breathing problems like asthma use it as a bronchodilator. Clenbuterol is a Beta2-adrenergic receptor agonist with similarities to ephedrine; however, its effects are more potent and lasts longer as a stimulant and thermogenic. The use of Clenbuterol causes an increase in aerobic capacity, increase in blood pressure and oxygen transportation. However, various studies have shown long term use can reduce exercise performance.
Clenbuterol is not a steroid, although it is often mistaken as one due to its use in athletics. Often referred to as "Clen", the drug is actually a veterinary drug used mostly on horses. It increases heart rate, and increases internal body temperature. Clen is a banned substance; however, it can be purchased with relative ease.
Clenbuterol Pill Profile (Clen)
Most studies done on Clenbuterol used rats or horses as the subjects, and many studies have documented the effects of Clen on exercise performance.
Several animal studies have shown the anabolic properties of Clenbuterol, increasing skeletal muscles - although without apparent increase in corresponding power output. This increase in muscle size has also lead to an increase in heart muscle size by as much as 20%. Evidence from these studies also suggest a decrease in physical performance due to long term use of clenbuterol by up to 40%. No studies of this sort has been performed on humans, and the amounts used in these animal studies are much higher doses than a human could safely consume. Some effects of Clenbuterol evident from these studies include:
Treatment with Clenbuterol increased size of both slow and fast skeletal muscles, and as well as the heart muscle; however without any increase in power output. 1
Clenbuterol treatment increased fatigability in Soleus and Diaphragm muscles by 30 to 40%. The results showed clenbuterol has positive effect on muscle growth and force generation, but has adverse side effects such as increased muscle fatigability and development of deformities. 2
It is reported that clenbuterol increases the lean- to fat conversion in livestock and is an illegal stimulating and growth promoter. Consumption of meat containing clenbuterol residues causes adverse health effects in human, reduces the performance in exercise and disturbs reproductive system & hormone response. 3
Treatment with clen exhibited cardiac hypertrophy where absolute heart mass increased by ~ 19% indicating strongly that chronic clenbuterol use adversely affects exercise performance in rats. 4
A few independent case studies involving Clenbuterol have also reported very rare, but serious cases of myocardial infarction, or heart attacks. In two unrelated cases, 2 otherwise healthy body builders aged only 26 and 17 experienced myocardial infarction from the use of Clenbuterol. It is a beta 2-agonist with anabolic properties that has not been seen previously with myocardial infarction. In a case of myocardial infarction in an otherwise healthy 26-year-old body-builder who recently used clenbuterol and anabolic steroids, synergistic effects of the two agents seem likely to have played a role in the myocardial infarction. 5
The above case was reported of a young bodybuilder using both clenbuterol and anabolic steroids. In another similar case of Myocardial infarction in a healthy 17 year old bodybuilder, only Clenbuterol alone was used. 6
Clenbuterol Cycle Dosage & Weight Loss
Clenbuterol is widely used in athletic circles for its positive effects on body composition where it decreases the body fat and increases fat free mass. Various animal studies have shown the use of Clenbuterol to reduce body fat mass, and increase fat free mass. In one study, clenbuterol without exercise decreased fat mass by 15.4% and clenbuterol with exercise decreased fat mass by 19.5%. The clen with exercise horses also increased fat free mass by 4.4%.7
The use of Clenbuterol results in down regulation of beta receptors, and therefore, it is should be used for only short periods of time. A clen cycle generally lasts 2 to 3 weeks with a break in between cycles lasting equal to or longer than the cycle itself. The cycle should start gradually, slowly increasing the Clenbuterol dosage and then tapering off gradually. The average dose of clenbuterol is 60 to 120 mcg/day. Your best course of action is to start slow with a low dose, gauge the effects it has on your body, see how well your body handles it, and then slowly increase the dosage accordingly.
1. Year-long clenbuterol treatment of mice increases mass, but not specific force or normalized power, of skeletal muscles.Lynch GS, Hinkle RT, Faulkner JA.
Institute of Gerontology, University of Michigan, Ann Arbor, USA.
2. Beneficial versus adverse effects of long-term use of clenbuterol in mdx mice.Dupont-Versteegden EE, Katz MS, McCarter RJ.
Department of Physiology, University of Texas Health Science Center at San Antonio, USA.
3. Zhang Y, Wu Y.
Institute of Nutrition and Food Hygiene, Chinese Academy of Preventive Medicine, Beijing 100050, China.
4. Deleterious effects of chronic clenbuterol treatment on endurance and sprint exercise performance in rats.Duncan ND, Williams DA, Lynch GS.
Department of Physiology, The University of Melbourne, Parkville, Victoria 3052, Australia.
5. Clenbuterol and anabolic steroids: a previously unreported cause of myocardial infarction with normal coronary arteriograms.Goldstein DR, Dobbs T, Krull B, Plumb VJ.
Department of Medicine, University of Alabama at Birmingham 35294-0007, USA.
6. Wei Sheng Yan Jiu. 2002 Aug;31(4):328-30.Links
[Toxicological effects of clenbuterol in human and animals][Article in Chinese]
7. Chronic administration of therapeutic levels of clenbuterol acts as a repartitioning agent.Kearns CF, McKeever KH, Malinowski K, Struck MB, Abe T.
Department of Animal Sciences, Rutgers, The State University of New Jersey, New Brunswick, New Jersey 08901, USA. J Appl Physiol. 2001 Nov;91(5):2064-70.