CAFFEINE is a quite common cosmetic ingredient. It can be found mostly in eye creams or anti-cellulite products but lately it has been added even to soaps or shower gels.

Chemical Name: Caffeine
Chemical Formula: C8-H10-N4-O2
Molecular Weight: 194.2 g/mole
Color: White.
pH (1% soln/water): 6.9 [Neutral.]
Solubility: The product is equally soluble in oil and water; log(oil/water) = -0.1.
Caffeine is moderately soluble in water at room temperature (2 g/100 mL), but very soluble in boiling water (66 g/100 mL). It is also moderately soluble in ethanol (1.5 g/100 mL). It is weakly basic (pKa = ~0.6) requiring strong acid to protonate it.
Incompatibilities with Other Materials: Strong oxidizing agents.
Hazardous Decomposition Products: Nitrogen oxides, carbon monoxide, irritating and toxic fumes and gases, carbon dioxide.
(Source: here and here)
KEEP ON READING