Clenbuterol, The Benefits, The Dangers, and The Misuse
Written by: THE BALANCE
Medically reviewed by Dr. Sarah Boss, MD
Last updated: January 19, 2026
Fact checked
Quick Summary
  • Clenbuterol has been popularized across the world as a non-steroidal drug with steroid-like effects.
  • Originally used to relax the muscles and open airways in people struggling with lung issues like chronic obstructive pulmonary disease and asthma, it has now become a hot topic due to its miscellaneous non-medical uses.
  • Over the years, studies have shown how clenbuterol possesses the ability to boost metabolism and improve stamina, thereby increasing fat-burning processes.
Reading time: 9 min

Clenbuterol has been popularized across the world as a non-steroidal drug with steroid-like effects. Originally used to relax the muscles and open airways in people struggling with lung issues like chronic obstructive pulmonary disease and asthma, it has now become a hot topic due to its miscellaneous non-medical uses.

Over the years, studies have shown how clenbuterol possesses the ability to boost metabolism and improve stamina, thereby increasing fat-burning processes. Its frequent use has also been associated with reduced muscle damage during physical exercise. The drug also prevents the body from getting fatigued due to increased performance and endurance, hence, becoming popular among bodybuilders, athletes, and other gym enthusiasts. Due to its ability to increase the rate of fat breakdown, some people have also turned to use clenbuterol to lose weight.

Despite the multiple off-label benefits, clenbuterol continues to be a controversial stimulant that comes with serious risks. If you or someone around you is planning to incorporate it into your life, it is imperative to familiarize yourself with the most common clenbuterol side effects for your safety.

Because clenbuterol is a stimulant, its short-term side effects are quite similar to other stimulants, such as amphetamines and coffee. These side effects largely vary based on the individual, especially in people who have developed some level of tolerance to the drug. Mentioned below are some common side effects of clenbuterol weight loss supplement, especially in people who are using it for the first time:

Increased blood pressure (source: MedlinePlus, n.d.)

Racing heart rate and palpitations

Dry mouth

Sleep disturbances

Tremors and shakiness, especially in hands

Increased anxiety, restlessness, and nervousness (source: NHS, 2024)

Vomiting and nausea

Heightened energy

Common symptoms of mania

Dizziness

headaches (source: NIDA, 2024)

Panic attacks

Intense sweating

Muscle cramps and spasms

Breathing difficulties

Increased body temperature (source: CDC, 2023)

Manic symptoms

Headaches, muscle cramps, and nausea are most common in users after a session of intense training. The severity, frequency, and intensity of these clenbuterol side effects are likely to vary from one person to another.

In addition to acute symptoms, clenbuterol can also trigger long-term side effects in people who continue using it for a longer duration of time. Mentioned below are the five dodgiest clenbuterol side effects males:

Uncontrollable Trembling

Clenbuterol works by manipulations it creates inside the nervous system. These manipulations cause uncontrollable shaking, especially in hands that continue to make it difficult to finish a task. This acute symptom can quickly turn into a long-term issue, hindering the simplest of daily activities. (source: NCBI Bookshelf, 2024)

Insomnia

Due to the stimulating properties of clenbuterol, this medication can make it difficult for some people to sleep at night. Moreover, because it enhances the process of fat burning, the amount of energy in the body increases which further induces insomnia-like symptoms. In the long run, this sleep deprivation causes enthusiasm to run out very quickly.

Sweating

One of the many mechanisms through which clenbuterol works is by increasing the core body temperature. This increased body temperature triggers fat cells and enhances the rate at which the body is breaking them down to release free fatty acids. While this may sound like good news to those trying to lose weight, others who are taking it for medical purposes may find themselves sweating profusely all the time.

Muscle Cramps

One of the ways clenbuterol works in the body is by increasing the amount of taurine and potassium it loses through urine. As the amounts of these two chemicals drop, users develop painful muscle cramps. For some, these cramps are so uncomfortable that they hinder them from doing everyday activities.

Muscle Deformities

Although the effect has not yet been observed in humans, the use of clenbuterol in animal studies has led to muscle deformities. Experts have raised concerns about counteracting similar side effects in human models, especially in users who have been using this drug for a long time.

Addiction

Because clenbuterol attaches itself to certain receptors in the brain and releases dopamine, it is capable of triggering the body’s reward system. In the long run, this effect can make the drug highly addictive and difficult to get off. (source: WHO, 2021)

Heart Attack

Clenbuterol increases the heart rate and generates abnormal heartbeats, chest pain, and palpitations in some users. In the long run, these symptoms increase the risk of a heart attack, especially in people who are already vulnerable to cardiovascular disease. Therefore, experts strongly discourage people with co-existing heart disease from using clenbuterol until it is necessary to manage a medical concern. The use of clenbuterol has also been associated with functional and anatomical heart changes, and some studies believe that it can even enlarge the heart and induce other related complications.

Drug Interactions

Due to the increasing popularity of clenbuterol and its off-label uses, many people have started taking it illegally without supervision. Such individuals usually do not let their physicians know about this illegal use and as a result, these healthcare professionals may prescribe medications that potentially interact with clenbuterol to produce serious side effects. For example, combining clenbuterol with other beta-2 receptor activators is particularly dangerous.

Similarly, combining it with drugs that use the same detoxification pathway in the liver can reduce or increase their efficacy and cause trouble for the users.

In general, women need lesser doses of clenbuterol than males to achieve the same benefits. However, this dose difference does not essentially remove the risks of side effects in females. Most side effects they encounter are similar to those faced by males, including increased heart rate, insomnia, sweating, and risk of cardiovascular complications. In most cases, these side effects are mild and tend to get better after using clenbuterol for the first couple of weeks.

Apart from the usual side effects of clenbuterol, females experience some additional risks. For instance, women using clenbuterol for weight loss may experience a disruption in their menstrual cycle. Some experts have also expressed concerns about the potential of this drug to affect fertility in females. Taking this drug for prolonged periods increases the risk of these life-changing side effects. This is one of the reasons why women must keep their daily dosage of clenbuterol as low as possible and avoid taking it without a doctor’s advice. (source: SAMHSA, 2023)

Unfortunately, if the side effects of clenbuterol related to fertility and menstruation develop, they may not go away even if the drug use is stopped altogether. There is a lack of research regarding the potential side effects of clenbuterol on the female anatomy. Moreover, how this drug can affect a developing baby is also not well understood, which is why experts warn against using clenbuterol during pregnancy and breastfeeding.

While clenbuterol remains an unsafe and potentially dangerous medication for most people, it is possible to manage some of its milder side effects by keeping the following precautions in mind:

  • Stick to very low doses of clenbuterol
  • Avoid using the drug in high doses in an attempt to seek faster or more pronounced benefits
  • Discuss with a doctor about adding a taurine supplement to your daily routine to minimize fatigue and muscle damage
  • Stay hydrated by drinking at least eight glasses of water a day
  • Do not combine clenbuterol with alcohol or any other carbonated drinks
  • Take your last dose of clenbuterol at least 6 hours before bedtime to tackle sleep issues
  • Avoid using any other drug with clenbuterol, such as cariprazine and carbimazole, as there is a risk of serious drug interaction and side effects. Always discuss with your doctor before adding a new drug to your daily routine.
  • Try clenbuterol cycle practices to avoid using it consistently.

FAQs

What is clenbuterol used for?

Clenbuterol is a bronchodilator medication that opens up air passages in the lungs that may become narrow due to muscle contractions or mucus buildup. It was originally approved for people with severe asthma or chronic obstructive pulmonary
disease (COPD). However, more recently, bodybuilders and athletes have been using it unofficially to burn fat, build muscle, and improve their sports performance. The drug can increase the development of skeletal muscles by improving muscle protein synthesis and aids in fat loss by enhancing the expenditure of resting energy.

What do you mean by clenbuterol cycling for weight loss?

Many people who use clenbuterol with the intention of losing weight do so in the form of cycles. There are different techniques for clenbuterol cycling; however, the most common one involves using the drug in two 8-week-long cycles per year.

Is clenbuterol a steroid?

Contrary to what most people believe, clenbuterol is not a steroid. Although it works very similarly to a steroid, it’s actually closer to a stimulant drug. Clenbuterol belongs to a class of medications known as beta-2 agonists, which were first developed to help individuals manage asthma symptoms. (source: WADA, 2024)

What is the mechanism of action of clenbuterol?

The mechanism of action adopted by clenbuterol involves activating the fight-or-flight system or the sympathomimetic system in humans. This activation leads to various effects, such as widening of the airways to improve airflow and to breathe in the lungs, increased muscle mass, enhanced burning of fat to release more energy, increased sweating, and preparation of the muscles for physical activity.

Is clenbuterol legal in the USA?

In most parts of the world, including the United States, clenbuterol is officially banned for human consumption by the FDA. The World Doping Agency (WADA) and the International Olympic Committee (IOC) have also banned the use of this medication as a performance-enhancing drug. Unfortunately, a large number of people still continue to use it for bodybuilding and weight loss.

Can Clenbuterol affect mental health?

Unfortunately, clenbuterol can negatively impact a person's mental health. These mental side effects include anxiety and depression that become prevalent as soon as someone stops using the medication. Additionally, some people also develop excessive moodiness secondary to this drug use.

How effective is clenbuterol for weight loss?

A lot of people have been using clenbuterol because of its supposed weight-loss properties. While it does seem to increase fat burning and oxidation in the body, keep in mind that it is only a supplement with potentially dangerous side effects. It will not likely cause any weight loss until you pair it with a healthy diet plan and exercise. Hence, it is always a good idea to talk to a specialist regarding weight loss and seek help from a safer and more effective approach.

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