Tuesday, February 26, 2013

Clenbuterol as a fat loss agent. By Vic Goyaram

Clenbuterol as a fat loss agent
 Researched and composed by Vic Goyaram

Clenbuterol: the new wonder 'mainstream' weight-loss drug
Clenbuterol (henceforth, Clen, for short) very often features in the fat burner arsenal of experienced competitive bodybuilders who probably have a decent understanding of the effects and side effects of the drug. However, I have recently been alarmed at the number of questions about Clenbuterol that I have received from a number of people who are most likely unaware of the basics of fat loss dieting and who have probably been told by their peers in the gym to use pop some Clen tabs to get ripped. In the pharmacies where I work part-time I often get women who come looking for Clen and Anavar for fat loss. 

This article is intended to give you a background on Clen, its effects and side effects in order to help you make an informed decision.  I have personally never used Clen and most of my experience comes from my understanding of biochemistry, pharmacology, physiology and my interaction with people who have used it for its physique enhancement effects.

The regulatory status of Clenbuterol

"Clen is not approved for human use in the US"
In the USA, Clen is not approved for human use even for medical purposes. It is only approved for use in horses suffering from respiratory problems. Clen is not intended for human use or for use in food producing animals in the USA. Outside the U.S., Clen is available on prescription for the treatment of breathing disorders like bronchial asthma in humans. Livestock producers in countries like Mexico and China use Clen in animals to improve meat quality. Clen is available in tablets (0.01 or 0.02 mg per tablet) and liquid preparations as Clenbuterol hydrochloride. 
In the US Clen is allowed only as a veterinary drug 

"Clen is listed as a banned substance by the WADA and natural bodybuilding federations"
Clen is listed by the World Anti-doping Agency (WADA) as a performance enhancing drug. Some natural bodybuilding federations like the International Natural Bodybuilding Association (INBA) list β-2 agonists like Clenbuterol and Salbutamol on their banned substances list as they follow the WADA protocol. 

Advertisement: Tired of wasting money, with no results?
I offer consultations on diet, supplements, training for your individual needs. No one-size fits all diet and exercise programs but custom-made programs. I tell you what supplements are worth investing your money on, based on your own needs. You get to ask me any and as many questions as you want if you are my student. At the end of the day, no more guess work, no more trial-and-error, no more wasting thousands of rupees on supplements that didn't do a damn for you. I tell you the secrets based on scientific research and my experience in the gym. They want to enrich themselves selling you products that may not work for you, me I enrich you with knowledge so you can go on and achieve bigger things. I haven't only been to school: I have been under the bar too! 

Here is my card:

Basic pharmacology of Clenbuterol
The chemical structure of Clenbuterol
Clen is a classified as a sympathomimetic drug. It is so named because it stimulates the sympathetic nervous system whose general action is to initiate a "flight or fight" response (an overall stimulant effect). Clen does this by activating receptors called β-2 adrenergic receptors. 

Stimulation of these β-2 adrenergic receptors gives rise to effects like:

  • Smooth muscle relaxation in the bronchi (bronchodilation). The main pharmacological use of Clen, asthma treatment, is in fact based on this effect.
  • Fat breakdown in adipose tissue (triglycerides broken down into fatty acids that can be oxidised) hence it's effect as a cutting drug.
  • Dilation of arteries that lead to skeletal muscle, allowing more efficient oxygen transportation to muscles.
  • Stimulation of anabolism in muscle (relevance of this effect in humans will be discussed below).
After ingestion, Clen is readily absorbed (70-80%) and remains in the body for awhile (25-39 hours). As a result of its long half life, the adverse effects of Clen (more below) are often prolonged.

Be seen by the 10,000 people who read this article every month!!
Clen use in bodybuilding

A. Thermogenic and stimulant effects
Clen is used at about 60-120µg per day by bodybuilders often in combination with other fat burner drugs like the thyroid boosting drug T3, Yohimbine and Ephedrine/ Caffeine/ Aspirin (ECA) stack. The dosage is split in several intakes of 20µg. First time users generally test their sensitivity to Clen for determining the dosage. Clen is a fast acting drug and results come very fast, nearly immediately. An increase in body temperature is generally noted which is typical of Clen's well-known thermogenic effects.
Bodybuilders in contest preparation mode also stack Clen with steroids like Winstrol, Anavar and Equipoise. Users also report an increase strength with Clen especially in the first 2-3 weeks of use. This is possibly due to the stimulant properties of the drug. 

B. Receptor down-regulation
The body gets used to Clen fairly rapidly because the beta receptors are rapidly down-regulated. This means that the number of receptors decrease in response to the excess of beta-agonist (Clen), a usual response of the body. That is why Clen is generally used for relatively short periods of time, usually 4-6 weeks and use drugs like Ketotifen to try keep the receptors up and running.
When the body sees too much Clen (beta-agonist), it will decrease
the number of beta-receptors as a means of protecting itself

C. Anabolic effects
I would like to elaborate a lot on this one because a lot of people have asked me about the anabolic effects of Clen because they have read about it and thus want to use Clen to avoid the side effects (including injection pain) of steroids. Stimulation of the beta-2 receptors activates anabolic pathways in skeletal muscle and is the mechanism by which Clen exerts its anabolic effects.  Besides its effects on fat loss Clen may also produce a mild anabolic effect. I know you must be thinking "Hell yeah, I found what I wanted! Losing fat while putting on a bit of muscle!". Please be warned that while the mechanism of beta-2 agonist  anabolism is well established these effects may not happen with the doses used in humans. Let me tell you why:

The anabolic effect of Clen has been found in animals and not in humans. In these studies large amounts of Clen were used which is far in excess of what is safe for human consumption and what is recommended for bronchodilation. In a study by Choo and colleagues (1992), an anabolic effect was seen in rats that were given 4mg of Clen per kg of bodyweight. This means 400mg Clen for a 100kg person. Now remember that common doses for fat burning is 60-120MICRO grams per day. Be careful not to extrapolate animal data to humans especially unsupervised drug usage. Some people I know have reported that they retain muscle very well on clen but then they were also using anabolics like Winstrol and Equipoise so they real anabolic contribution of Clen cannot be determined. 

Below are two good review articles on the topic of Clen use to increase muscle mass and both come to the agreement that knowledge of the effects of Clen on muscle come from animal (laboratory or slaughter stock) experiments and not human data and therefore cannot be extrapolated to humans. Experiments on the safety, efficacy and cardiovascular side-effects are needed.
(Spann and Winter, 1995)
(Prather et al., 1995)

Side effects
Although the reported fat burning effects of Clenbuterol are fantastic it doesn't come without a share of serious side effects. These side effects can be classified as follows:
  • Psychological side effects: As Clen is a nervous system stimulant emotional side effects are known to occur with its use. Many people report severe nervousness, paranoia and anxiety. Tremors are also very common and this reduced one's ability to perform physical tasks like writing, typing and holding objects. Insomnia may also result from Clen use especially when you have built up your dose. People who already suffer from psychological disorders like depression and anxiety are most likely to be at greater risk to experience the psychological side effects of Clen. Should you fall under such category it is best to speak to your medical practitioner before taking Clen. Do not play with your mental health.
  • Short and long term cardiovascular side effects: Clen users report that cardiovascular side effects appear quite rapidly. These side effects include tachycardia (heart palpitations) and high blood pressure and the headaches that accompany these. In some users these side effects have been enough to get them to quit using Clen. In experiments using rats, the long term use of Clenbuterol has been to cause an infiltration of collagen fibres in the heart wall. Collagen stiffens the heart muscle and reduces its functionality. Most Clen use is unsupervised and its consequences in people with pre-existing heart conditions and hypertension are not to be taken lightly. Taking Clen under these conditions can be a tragedy waiting to happen.  There have been cases of sudden death with Clen use.
  • Cramps: Clen is known to cause some bad cramps because it depletes the amino acid taurine. Taurine supplements help against Clen-induced cramps.
"Jumping" on Clen

First of all, I do not recommend Clenbuterol as a fat burner is you haven't mastered the basics of dieting like sorting out your diet and exercise program. Do not think you can get away by popping Clen tabs on a poor diet.  Do not look shortcuts and rather educate yourself. Do not listen to the guy who is selling you Clenbuterol and telling you "just drink this" without even talking about a proper diet strategy with you and asking about your medical history. Clen isn't your typical fat burner sitting on the shelves in the supplement store. Clen is serious business. Most of the questions about Clen use that I have received are from people who are clueless about their own nutrition. Imagine my horror when they also told me that they are doing endless sit-ups with no results and cannot answer me about the approximate number of calories they consume. I hope this article has shed some light on this topic. For those who want to learn more about dieting basics I will recommend the following two articles. Please read them carefully to know how your eating should be like before considering the use of Clen. They are written by two of my role models, Doug Brignole and Dr. Layne Norton.

The Ultimate Cutting Diet – Devised By Pro Natural Bodybuilder Layne Norton


Choo J.J, Horan M.A ,Little R.A, and Rothwell N.J. Anabolic effects of Clenbuterol on skeletal muscle are mediated by beta 2-adrenoceptor activation. Am J Physiol Endocrinol Metab July 1, 1992 263:(1) E50-E56

Prather ID, Brown DE, North P, et al. Clenbuterol: a substitute for anabolic steroids? Med Sci Sports Exerc 1995 Aug; 27(8):1118-21

Spann C, Winter ME.Effect of Clenbuterol on athletic performance. Ann Pharmacother. 1995 Jan; 29(1):75-7.

Join us for discussions on our facebook group
Free advice & daily bodybuilding talk
Your #1 Bodybuilding destination in Mauritius 

My Bio: I am a Mauritian originally from Roche Bois, Port Louis and now based in Cape Town, South Africa where I am busy with my postgraduate studies in molecular biology of exercise. My research, supervised by Prof. Edward Ojuka, looks at the influence of nutrition and exercise in gene expression in muscle, research which is relevant and applicable to exercising individuals, sports persons and diabetic individuals. The knowledge that I share with you stems from my 18 years of experience in bodybuilding and 8 years (and counting) of university education in the field. I have also published work in the American Journal of Physiology: Endocrinology and Metabolism (2013), International Journal of Sport Nutrition and Exercise Metabolism (2013) and co-authored two book chapters on exercise and diabetes. I also presented my research work at the 2012 International Sports and Exercise Nutrition Conference (UK). I am grateful to each and everyone at the UCT Research Unit for Exercise Science and Sports Medicine. "Knowledge without sharing is worth nothing"
Join us for discussions on our facebook group
Free advice & daily bodybuilding talk
Your #1 Bodybuilding destination in Mauritius 
©,2013, Veeraj Goyaram, Bodybuilding Mauritius. Any reprinting in any type of media is prohibited.
Disclaimer: The Content on this site is intended to be used for educational and entertainment purposes only. It is not intended to be and should not be interpreted as medical advice or a diagnosis of any health or fitness problem, condition or disease; or a recommendation for a specific test, doctor, care provider, procedure, treatment plan, product, or course of action. BODYBUILDING MAURITIUS is not a medical or healthcare provider and your use of this site does not create a doctor / patient relationship. We disclaim all responsibility for the professional qualifications and licensing of, and services provided by, any physician or other health providers posting on or otherwise referred to on this Site and/or any Third Party Site. Never disregard the medical advice of your physician or health professional, or delay in seeking such advice, because of something you read on this Site. We offer this Site AS IS and without any warranties.  Correspondence: vicgoyaram@gmail.com


  1. Good Stuff Vic, thanks for posting the side effects. I would avoid Clen like the plague. Caffeine is safer and if used wisely can help you with your cutting. I know of a Prominent Cardiologist who does bodybuilding also and he would not touch Clen due to irreversible Heart Chamber damage and tachycardia requiring long term beta blockers or pacemaker.