The most common side effects associated with the whole group of stimulants are: tremor (shaking hands), insomnia, sweating, headache, increased blood pressure, and feeling sick. Side effects are quite common and likely to occur in each individual taking clenbuterol.
High dose for the purpose of burning fat is usually in the range of 120 – 160mcg daily. However, no one should start at this dose for safety reasons. A rapid increase in dosage or immediate administration of the maximum dose can be very unpleasant and even fatal. Therefore, it is strongly recommended that individuals slowly and gradually increase the clenbuterol dose every day. The first dose should be 20 – 40mcg, and every third day another 20mcg can be added. Clenbuterol is detectable in urine for 20-25 days.