Description
Clenbuterol is a selective beta-2 adrenoceptor agonist, originally approved as a bronchodilator in veterinary and human medicine (in some countries). Per study reports the compound is primarily relevant for its thermogenic and anti-catabolic properties.
Per study reports Clenbuterol activates beta-2 receptors in skeletal muscle, cardiac muscle and adipose tissue. The result is increased cyclic AMP concentration in target cells, stimulating lipolysis, glycogenolysis and thermogenesis. Body core temperature typically rises by 0.5-1.0°C, basal metabolic rate by 10-20%.
A second important property in anabolic research literature is the anti-catabolic effect: in animal studies Clenbuterol shows muscle-protective action during caloric deficit. The mechanism runs via suppression of proteolysis pathways and stimulation of muscle protein synthesis.
Pharmacokinetics are favorable: oral with about 26-34 hour half-life, allowing once- to twice-daily dosing. Known and very dose-dependent effects: tremor, palpitations, sleep disturbances, muscle cramps (hypokalemia-mediated), sweating.
The main issue is cardiac safety: animal studies show cardiac hypertrophy and fibrosis with longer use. In human medicine there are case reports of tachyarrhythmias and (very rarely) myocardial infarctions under Clenbuterol abuse. Recreational research protocols therefore typically stay limited to 2-3 weeks with subsequent breaks.
You can order Clenbuterol as oral tablets in one bottle with 40mcg per tablet.
This information is for research and educational purposes only. No medical recommendations.
Risks & Safety
Clenbuterol sits at the high end of the risk scale. The compound is highly effective, but its cardiac effects are consistently and seriously documented in the literature.
Documented in studies and the literature:
- Cardiac strain: tachycardia and palpitations are documented dose-dependently. Animal studies show cardiac hypertrophy and fibrosis with longer use.
- Tremor: pronounced shaking, especially of the hands, is one of the most commonly documented observations.
- Electrolyte shift: beta-2 activation drives hypokalemia, with muscle cramps as the lead symptom. Taurine depletion is also described in the literature.
- Anxiety and sleep disturbance: inner restlessness, nervousness and insomnia are consistently documented under Clenbuterol.
- Arrhythmia cases: human medicine has case reports of tachyarrhythmias and, very rarely, myocardial infarction under Clenbuterol abuse.
Monitoring via bloodwork is recommended. This classification does not replace medical advice. Risk and responsibility for any actual use lie entirely with the buyer.
Studies
- Clenbuterol induces lean mass and muscle protein accretion, but attenuates cardiorespiratory fitness and desensitizes muscle beta2-adrenergic signalling - The Journal of Physiology 2025, Hostrup et al: randomized placebo-controlled trial in healthy men, documents lean mass gain alongside reduced cardiorespiratory fitness and beta-2 receptor desensitization.
- Cardiac, pulmonary and neuromuscular effects of clenbuterol and terbutaline compared with placebo - British Journal of Clinical Pharmacology 1981, Whitsett et al: clinical comparative study of cardiac, pulmonary and neuromuscular effects of oral clenbuterol doses in humans.
- Effects of clenbuterol on skeletal muscle mass, body composition, and recovery from surgical stress in senescent rats - Metabolism 1991, Carter et al: animal study on the anti-catabolic effect, documents muscle mass and carcass protein gains across age groups.
- Comparison of the effects of salbutamol and clenbuterol on skeletal muscle mass and carcass composition in senescent rats - Metabolism 1994, Carter et al: direct comparison of two beta-2 agonists on muscle mass effects in an animal model.
- Effect of Clenbuterol on Recovery of Muscle Mass and Carcass Protein Content Following Dietary Protein Depletion in Young and Old Rats - Journal of Gerontology 1994, Carter et al: documents accelerated muscle mass recovery after protein depletion in an animal model.
