Clenbuterol is a powerful bronchodilator commonly used to treat asthma and other respiratory conditions, but it has also gained popularity for its fat-burning and performance-enhancing properties. Despite its benefits, understanding what is clenbuterol side effects is crucial before considering its use. Clenbuterol side effects can vary from mild to severe and may affect different individuals differently. Common side effects include increased heart rate, palpitations, and elevated blood pressure, which can pose serious risks for those with cardiovascular issues. Users often report nervousness, anxiety, tremors, and headaches due to clenbuterol’s stimulating effects on the nervous system. Insomnia is another frequent complaint, as clenbuterol can disrupt normal sleep patterns.