You might not want to believe me, but it’s fact: you cannot sweat out toxins. Sweat is composed of 99% water and a tiny percent of salt, urea, proteins and carbohydrates. Salt, proteins and carbohydrates are natural.Urea is a by-product of protein metabolism and is non-toxic.he water evaporates from your skin, cooling you. Excess sweating doesn’t eliminate excess salt or help hangovers. By forcing your body to copiously perspire, you’re only forcing your kidneys to save water (and ironically actual toxins) elsewhere.