Salbutamol

What salbutamol is and how it works

Salbutamol, called albuterol in the US, is a short-acting beta-2 agonist. In Germany it is prescription-only, for example as Sultanol metered-dose inhaler, and approved for the prevention and treatment of respiratory diseases with narrowed bronchi such as asthma, chronic bronchitis and pulmonary emphysema. In acute shortness of breath it acts within a few minutes.

Salbutamol activates beta-2 adrenoceptors and thereby relaxes the smooth muscle of the bronchi. The same receptors are also found in skeletal muscle, the heart and fat tissue. In muscle, their activation can stimulate protein synthesis and shift fiber types: in a training study, slow fibers converted into fast type IIa fibers, and these grew more than under placebo (Jessen 2021). In the short term, salbutamol raises the resting metabolic rate (Liu 2015), the heart rate rises, and the potassium level in the blood can fall (prescribing information). With a half-life of about 6 hours after infusion, salbutamol acts considerably shorter than clenbuterol.

What the studies show

Strength, sprint and power: meta-analysis of 34 studies

Riiser 2020 pooled 34 randomized, placebo-controlled trials with 472 healthy participants without asthma that tested performance lasting up to one minute. Overall, beta-2 agonists improved this performance by about 5 percent. The effect depended strongly on dose and form: inhaled it was small (standardized difference 0.16), as a tablet considerably larger (0.51); with doses permitted in sport small (0.14), with banned doses larger (0.46). Strength and sprinting benefited; whether WADA-compliant doses improve performance is uncertain according to the authors.

Endurance: meta-analysis of 47 studies

Riiser 2021 analyzed 47 studies on performance lasting more than one minute. Beta-2 agonists had no effect on endurance performance, time trials, time to exhaustion or maximal oxygen uptake, regardless of substance, dose, route of administration, duration and training status. Consistent with this, inhaled salbutamol improved lung function in 49 trained cyclists, but not performance in a 10 km time trial, with and without exercise-induced asthma (Koch 2015).

11 weeks of resistance training with salbutamol tablets

Jessen 2021 randomly assigned 26 young men to salbutamol tablets or placebo; both groups trained three times a week. Mean power in a 10-second sprint rose by 12 percent under salbutamol and by 7 percent under placebo; peak power and muscle strength rose equally in both groups. The fast type IIa fibers grew by 35 versus 21 percent, and fiber types shifted toward type IIa only under salbutamol.

Muscle mass, heart and endurance at high doses

Hostrup 2026 studied 30 trained men around 23 years of age who took salbutamol tablets at a dose well above therapeutic levels, or placebo, for 11 weeks and did resistance training three times a week. Fat-free mass rose by 1.8 kg more under salbutamol than under placebo. On cardiac MRI, heart structure and function did not differ, but on ultrasound the heart walls were thicker under salbutamol. Time to exhaustion in the exercise test rose by 7 percent under placebo, but not under salbutamol; capillary density and oxidative enzymes in the muscle decreased. The authors speak of a trade-off between muscle gain and harm.

Metabolism and fat loss

Liu 2015 showed that albuterol, that is, salbutamol, raises the resting metabolic rate in humans in the short term. More fat-free mass and less fat mass were found in this work only in rats, most clearly in combination with caffeine. A human study demonstrating fat loss through salbutamol does not exist so far.

Where the data stop

• Dose. The clear muscle effects come from studies with tablets at doses above therapeutic levels. Whether inhaled salbutamol at a permitted dose improves performance is uncertain according to the meta-analysis (Riiser 2020).
• Fat loss. Evidence in humans is lacking; the data on body composition come from animal experiments (Liu 2015).
• Duration and heart. The training studies ran for 11 weeks with 26 and 30 men. What the thicker heart walls mean in the long term is open.
• Women and older people. The training studies included only young men.

Status, approval and legal

In Germany, salbutamol is an approved, prescription-only medicine. One puff of the Sultanol metered-dose inhaler contains 100 micrograms; according to the prescribing information, the dosage depends on the type and severity of the disease. It is not approved for muscle building, performance enhancement or fat loss.

In sport, under the 2026 WADA Prohibited List, all beta-2 agonists are listed under S3 and banned at all times. The exception is inhaled salbutamol up to a maximum of 1,600 micrograms in 24 hours, divided into individual doses of no more than 600 micrograms in 8 hours. A urine level above 1,000 nanograms per milliliter is considered an adverse analytical finding, unless the athlete proves in a controlled pharmacokinetic study that it resulted from a permitted inhaled dose. Tablets are therefore always banned in sport. The prescribing information points out that use can lead to positive results in doping controls.

Unlike clenbuterol, salbutamol is not listed in the annex of the German Anti-Doping Act; possession, even of larger quantities, is therefore not prohibited under § 2 (3). Manufacturing, trading, supplying and prescribing it for doping in sport, by contrast, are prohibited under § 2 (1), because the substance is on the international Prohibited List.

Safety

In therapeutic use, the prescribing information lists tremor, headache, racing heart and elevated blood sugar as common, restlessness and palpitations as occasional, low potassium as rare, and cardiac arrhythmias including atrial fibrillation as very rare. Potassium falls more sharply in combination with theophylline, cortisone, diuretics or digitalis. Clearly exceeding the single or daily dose can be dangerous because of the effect on the heart. Caution applies in severe heart disease, racing heart, untreated high blood pressure, hyperthyroidism and diabetes that is difficult to control.

For use without an indication at high doses, so far only one randomized trial provides cardiac data: on ultrasound the heart walls became thicker, on cardiac MRI there was no difference; at the same time, the endurance adaptation to training failed to occur, and the oxidative capacity of the muscle declined (Hostrup 2026). The severe poisonings known from clenbuterol concern a different, much longer-acting substance and cannot simply be transferred.

Sources

• Sultanol metered-dose inhaler prescribing information, as of 11/2025 – indications, side effects, note on doping controls (German)
• NADA – 2026 Prohibited List, informational German translation (S3 beta-2 agonists, exception for inhaled salbutamol)
• Riiser A et al., Br J Sports Med 2020 – meta-analysis: beta-2 agonists and strength, sprint and power, 34 RCTs
• Riiser A et al., Br J Sports Med 2021 – meta-analysis: beta-2 agonists and endurance performance, 47 RCTs
• Hostrup M et al., Scand J Med Sci Sports 2026 – RCT: high-dose salbutamol in resistance training, fat-free mass, heart and muscle, 30 men
• Jessen S et al., J Appl Physiol 2021 – RCT: salbutamol in resistance training, fiber types and sprint performance, 26 men
• Koch S et al., Br J Sports Med 2015 – RCT: inhaled salbutamol and time-trial performance in 49 cyclists
• Liu AG et al., Obesity 2015 – caffeine and albuterol: resting metabolic rate in humans, body composition in rats
• German Ordinance on Prescription-Only Medicines (AMVV), Annex 1 – prescription requirement
• German Anti-Doping Act (AntiDopG), § 2 – prohibited handling of doping substances