Fact
Human sweat contains urea and ammonia. Urea is added to cigarettes.
Source 1:
Covington, and Burling. "Summary Of Data On Urea." Truth Tobacco Industry Documents, 17 Apr. 1986. Excerpt.
Source 2:
Pankow, JF, et al. "Conversion of nicotine in tobacco smoke to its volatile and available free-base form through the action of gaseous ammonia." American Chemical Society. 1997. 31(8): 2428-2433.
Source 3:
Huang, CT, et al. "Uric acid and urea in human sweat." Chinese Journal of Physiology, 30 Sept. 2002. 45(3): 109-15.
Source 4:
Foster, K.G. "Composition of the Secretion from the Eccrine Sweat Glands of the Cat's Foot Pad." The Journal of Physiology, 1966. 184(1): 106-09.
Source 5:
"Cigarette Ingredients. R.J. Reynolds List of Ingredients." R.J. Reynolds. 2013. Web.