Review title is Fast acting; the cooling lasted about 90 mins., before room temperature was achieved [SEP] Hola: due to the salicylic acid, there is a limit as to how many times to apply each 24 hours.  I would take two acetaminophen, apply Ken's Best Sportarub, and sleep, hard, for 90-120  minutes.  I'll purchase again.  Cuidate, CL