Clenbuterol: What is it Used To – Side Effects & Dangers

Clenbuterol: What is it Used To – Side Effects & Dangers

Clenbuterol is a controversial stimulant that has a variety of effects on the human body. Even though it might enhance breathing and is utilized off-label by bodybuilders looking to lose weight and gain muscle, it comes with serious dangers. Read along to find out more about the effects, side effects, and hazards of clenbuterol.

Disclaimer: We strongly urge against taking clenbuterol for any reason. A number of our subscribers who were taking the drug requested that we commission a post on it, and we are just providing information that’s available in the clinical and scientific literature.

The FDA has not approved clenbuterol to be used in people. Veterinarians administer clenbuterol to clear airway obstruction in horses, and out of the United States, it’s occasionally used as a treatment for chronic obstructive pulmonary disease (COPD). It’s important to discuss your medications with your doctor and to never take a drug with no prescription and supervision of a licensed medical practitioner.

What is Clenbuterol?

Clenbuterol is a synthetic stimulant (not a steroid), with similar short-term effects to other stimulants (such as amphetamines or ephedrine). These include increased heart rate, blood pressure, breathing, and metabolism. Actually, it was initially developed to promote mass gain from animals. Long-term utilization in animals has been linked to greater muscle mass and reduced fat, but no clinical studies have found similar results in humans.

Clenbuterol | Benefits | Brands | Cycles | Side Effects | Worth Risk?

Clenbuterol has multiple trade names, including Spiropent, Dilaterol, Ventolase, and NAB 365.

Clenbuterol Mechanism of Action

Clenbuterol activates the fight-or-flight system in humans (“sympathomimetic”). Its effects include:

  • Widening the airways to improve breathing and increase oxygen to the lungs (bronchodilator).
  • Increasing heart rate, and blood pressure.
  • Sends more blood to the muscles to get ready for physical activity.
  • Increasing muscle mass (catabolic) and burning fat to get additional energy.

It also raises sweating and short-term toxicity presents likewise to other stimulants (amphetamine or ephedrine).

Although varied, all of the effects are caused by activating beta-2 receptors located throughout the body.

Clenbuterol – Higher The Risk Of Side Effects


Clenbuterol triggers expansion prevents breakdown and speeds recovery of muscles. It stimulates protein production in cells, which eventually increases muscle mass (via beta-2 activation).

Muscle gain induced by clenbuterol happens because of increases in general protein amounts and creatine kinase. Creatine kinase increases muscle mobile connecting (myoblast fusion), an integral process in the formation and repair of muscles.

Clenbuterol also prevents muscle and protein breakdown after nerve damage, allowing the muscles to rebuild.

These findings come from animal research simply; no clinical studies have found similar effects in humans.

Genetics and Clenbuterol

The Effects of clenbuterol may vary based on someone’s genetics. Genetic variants in the beta-2 receptor in various individuals may change the body’s reaction to clenbuterol.

In Mice, clenbuterol caused changes in the activated genes to the beta-2 receptor, proteins involved in fat metabolism, and several muscle tissues. It may cause significant changes in humans also, which may have varying consequences.

In research on pigs, clenbuterol triggered improved the creation of many enzymes (in fat cells) involved in fat metabolism, decreasing fat stores along with also the size of fat cells.

A study on cells showed that clenbuterol raises levels of a genetic regulator (histone demethylase JHDM2a) by triggering beta-2 receptors (via protein kinase A pathway). This regulator regulates metabolic (and other related) genes, which reduces the size of fat cells.

Once Again, it’s important to remember that no human studies have found links between clenbuterol and the activity of any genes. This branch of research is highly speculative, and individual research will be asked to determine what relationship — if any — is different involving clenbuterol and human genetics.

Is Clenbuterol Legal?

Clenbuterol import for sale or human usage is prohibited in most states and is approved for human consumption from the FDA. Regardless of this, clenbuterol use is still high among bodybuilders and people looking for quick weight loss.

The World Doping Agency (WADA) and the International Olympic Committee (IOC) have banned clenbuterol as a performance-enhancing drug.

However, clenbuterol is still used in certain countries for treating asthma.

Clenbuterol is illegally used to boost expansion in livestock.

Contaminated Meat

Clenbuterol Was prohibited for livestock in many countries since large amounts of this drug can enter the body when eating the contaminated meat. That appeared to be true for Spanish cyclist, Alberto Contador, that failed a Tour de France drug test in 2010.

There are a number of other reports of clenbuterol-contaminated meats in different states:

  • 140 people in Spain hospitalized after ingesting meat (veal) tainted by clenbuterol.
  • 336 people in China poisoned after eating contaminated pork.
  • 50 cases of food poisoning in Portugal reported by lamb and beef contamination.
  • 62 people in Italy reported influenced by meat (veal) infected with clenbuterol.

How Long Can it Stay in Your System?

Clenbuterol is detectable in urine after multiple doses. Additionally, it may be found in hair samples one month after intake.

Uses of Clenbuterol

Clenbuterol Is illegal for humans in many countries, and we therefore strongly recommend against using it for almost any reason. The following is a summary of the available research on clenbuterol, a lot of that was conducted before the dangers of the drug were fully explained.

1) Enhances Breathing

Clenbuterol Improves asthma by improving obstructed breathing. It relaxes and widens blood vessels. This raises the quantity of oxygen from the blood and increases the body’s capacity to use oxygen for energy (aerobic respiration).

In two distinct studies (double-blind randomized controlled trials), clenbuterol significantly improved breathing in asthmatic patients. Clenbuterol needed a more rapid-onset and long-lasting effect in comparison with salbutamol.

In Addition, varying doses of clenbuterol were administered to 12 children with acute asthma. This significantly expanded their airways compared with the placebo.

Some states still use clenbuterol in people as a decongestant and bronchodilator. However, there are many safer alternatives.

Clenbuterol is also frequently utilized to treat breathing problems in horses.

2) Fat Burning

In animals given doses much greater than those required to unwind the airways, clenbuterol decreased fat mass over other fat burners, such as ephedrine. This is because of increased metabolic energy (thermogenic effect). But, the doses tested on these animals are deadly in humans.

Clenbuterol increases heart rate and blood pressure. This also leads to an increase in metabolic activity and body temperature, which then burns more fat and stored carbohydrates (glycogen).

Athletes Often illegally use clenbuterol as a fat-loss drug during cutting cycles. 19 people with chronic heart failure treated with clenbuterol (randomized controlled trial) had a significant increase in lean muscle and lean-to-fat ratio. These effects are also seen in rats and horses.

3) Muscle Growth and Healing

Clenbuterol Boosts the healing of patients from surgery. 20 healthy male patients (double-blind randomized controlled trial) were treated with clenbuterol for a month following operation (knee). Clenbuterol caused faster rehabilitation of muscle strength. Though these results are promising, the study was very small, and additional study is required into clenbuterol’s possibility of treating muscle-wasting conditions.

Clenbuterol Induces muscle growth by increasing the production of protein and diminishing muscle loss. Clenbuterol utilized on rats led to a marked increase in muscle mass and protein production rates. Additionally, muscle fibers became heavier in pigs using clenbuterol.

Although, Clenbuterol did not increase protein manufacturing in one study in rats. Rather, muscle-building was due to reduced protein breakdown.

A Study in rats indicates that the impact of clenbuterol is muscle-specific with fast-twitch muscles growing more rapidly and degrading less. Fast-twitch muscles are used in strong, rapid bursts of activity.

Though Now illegal in many countries, the meat industry has used clenbuterol to improve lean body mass (muscle) in animals for years.

4) Muscle-Degrading Requirements

16 patients using a muscle-degrading condition (muscular atrophy) were treated with clenbuterol. This significantly improved their freedom and reduced the worsening of the status. In accordance with this one small study, clenbuterol might have possible use in keeping muscles that are unused because of disease or injury. Notice, nevertheless, that clinical trials never followed up on this potential due to the hazards of clenbuterol.

Clenbuterol Therapy (6-18 months) improved the condition of four patients using a muscle-degrading disorder (muscular dystrophy).

Clenbuterol and Nerve Damage

71 Patients (double-blind randomized controlled trial) with neurological damage (brachial plexus injury) that results in muscle degradation were treated with a placebo or clenbuterol for 3 months. Those treated with clenbuterol had improvements in their muscle-related condition.

Clenbuterol and Burns

Muscle Degradation may occur as a result of a burn injury. Clenbuterol effectively reversed muscle degradation brought on by tissue burns in rats.

5) Stimulant

Athletes Utilize clenbuterol as a power enhancer. This is because clenbuterol acts similar to adrenaline in the body (activation of the sympathetic nervous system). It is regarded as a performance-enhancing medication by many sporting authorities.

A stimulant, clenbuterol temporarily increases alertness, focus, and energy. This can make workouts much more pleasurable and invigorating. Furthermore, users may experience a suppressed appetite and improved motivation, competitiveness, and aggression while working out.

6) Urinary Urgency

Clenbuterol improved symptoms by 65% in a study of 30 women with urinary urgency after fourteen days. Note that this was a tiny study conducted in 1986, and it had been abandoned as a result of the apparent dangers of this drug.

7) Labour Complications in Plants

Due To its muscle relaxant effects, clenbuterol is utilized in livestock to decrease labor complications. This indication was never investigated in humans because of the risks clenbuterol carries. In cattle, clenbuterol and corrected birth-complications, reducing the need for anesthesia. But even in animals, this class of drugs may cause adverse effects, such as an increase in heart rate, bleeding, and birth defects.

Dosage of Clenbuterol

Formerly utilized at low doses as an effective bronchodilator, clenbuterol use is currently confined to veterinarians and investigators. As such, there are no clear clinical dosage guidelines to follow.

Websites and sites selling clenbuterol may give extra information on dosing, which can be dangerous due to the lack of research and severe dangers. Recall that clenbuterol is just approved for use in horses and is regarded as too hazardous to be used in humans.

Side Effects and Interactions of Clenbuterol

Clenbuterol use can be dangerous, with many potential short- and long-term side effects. Clenbuterol is extremely powerful — very tiny doses are needed to get the effects. Unfortunately, this may lead to more overuse, overdose, and inadvertent poisoning.

Complications mainly arise from athletes abusing clenbuterol for performance enhancement. There have also been instances of clenbuterol poisoning from food contamination in Portugal and Italy.


Because Clenbuterol is a stimulant, short-term unwanted effects are similar to other stimulants like java and amphetamines. These can largely vary based on the person, especially if a certain level of tolerance is accomplished. The following are frequent short-term unwanted effects, particularly in first-time customers:

  • Increased blood pressure, heart rate, and palpitations
  • Insomnia
  • Dry mouth
  • Vomiting and nausea
  • Tremors (shakiness, particularly marked in palms )
  • Stress, Panic attacks, anxiety, and restlessness
  • Headaches
  • Breathing difficulties and rapid breathing
  • Intense sweating
  • Muscle cramps and migraines (due to dehydration or decreased potassium)
  • Dizziness
  • Increased body temperature
  • Manic symptoms (heightened energy)

Headaches, nausea, and muscle cramps are common after intense instruction. Clenbuterol also depleted taurine, which protects the heart, and potassium, which is vital for muscle movements.


The Long-term side effects of clenbuterol are mostly unknown. Most are recorded instances of athletes using clenbuterol for performance-enhancement.

Muscle Deformities

Although not seen in people, clenbuterol use caused muscle deformities and fatigue in mice.


Clenbuterol functions on dopamine, the body’s reward system, also can be quite addictive.

Heart Attack

Clenbuterol can increase heart rate (tachycardia), in addition, to cause abnormal heartbeats, palpitations, and chest pain. This increases the risk of a heart attack, particularly in those who are already vulnerable.

One patient with clenbuterol (and solifenacin) developed a severe and potentially fatal abnormal heartbeat (Torsade de Pointes).

In horses, clenbuterol should be avoided in those With existing heart problems or higher blood pressure. This usually means that clenbuterol might be particularly dangerous for people with heart disease.

In studies on rats and mice, clenbuterol caused anatomical and functional heart effects, including augmentation, which can have harmful effects.

Drugs Interactions of Clenbuterol

Many Folk are taking clenbuterol illegally and unsupervised. Physicians unaware of the patients’ clenbuterol use could prescribe medications that interact with this medication.

The Combination of clenbuterol along with other beta-2 receptor activators may be harmful and increase the possibility of serious unwanted effects.

Clenbuterol Is divided by CYP enzymes (CYP1A1 and 1A2), which might affect the activity of other drugs that use the exact same detoxification pathway.

Limitations and Caveats

Available evidence limits clenbuterol use in people. Just a few elderly double-blind studies or several cohort studies exist. But, there are lots of veterinary studies, a few of which may have consequences for individuals.

Additionally, Every time a low-cost drug is found to be harmful in humans, it is still frequently utilized in animals. This might be because it’s not quite as dangerous for the creatures, or the side effects are less suitable in people. That is how it is for clenbuterol, which is exactly why so much research can be found on animals and not humans.

There are other drugs that are as powerful as clenbuterol in people, with fewer unwanted effects. This adds to the lack of clinical research on clenbuterol, where the benefit to risk ratio is too low for the study to be well worth it.

A clinical study on clenbuterol was abandoned because of unacceptably high risk in people. Animals (horses, in particular) can tolerate the types of doses necessary for positive results on fat and muscle — even corrected for fat, similar doses of clenbuterol would kill a human being.

User Experiences & Abuse

Weight Reduction

Users say that clenbuterol assisted them to burn a few more calories but was not worth the side effects.

Many people noticed tolerance after more than 2 months, as the body gets used to its consequences. Bodybuilders abuse it in cycles.

1 brand new user said that the body temperature rapidly increased, felt hot-headed and nervous for a minimum of 30 minutes.

Performance-Enhancement Abuse

Athletes and fitness center users misuse clenbuterol for a performance-enhancer to maximize their energy levels, weight reduction, endurance, and diminished appetite.

Muscle Shaping

Bodybuilders abuse clenbuterol in a cutting cycle to acquire extra shredded for vanity purposes or for the contest.

One Realtor attained weight loss but underwent severe muscle cramps in toes, fingers, legs, and jaw.


Clenbuterol Is an illegal stimulant that a number of bodybuilders believe can help them lose weight and gain muscle. However, in its early clinical trials exploring its impact on the airway, clenbuterol has been found to be too dangerous to develop for human usage. The dosages required for this medication to influence muscle development could quite likely kill the individual user.

Clenbuterol’s Myriad unwanted effects include increased blood pressure, nausea, and insomnia. In the long term, it can lead to dependence, muscle deformities, And heart attack. We urge strongly against using clenbuterol to get Any objective.

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