This product is really the one I prefer. At the dosage that suits me I feel a real but gentle stimulation and without its bad effects (palpitations, nervousness, anxiety) that lasts several hours. Does not prevent me from sleeping. The quality of the product is constant and allowed me to find a balanced dosage. The delivery is very fast, I recommend to take the delivery insured because in case of seizure by the customs the free redirection is assured.