Depends on the person. Depends on how much is in the product. Depends on if the product is good quality and actually works. If you're concerned, don't use it, and fix your skin by eating better and better hygiene and eliminating artificial ingredients in the products you use on your skin. Some people have very sensitive skin, some don't. You only find out which one you are by trying the product and there is no health reason to use such a product, so again, if you are concerned, try a different method of accomplishing your purpose. Otherwise, it's just trial and error.