Regenerist Thermal Skin Polisher ($13.99 for 4.2 ounces) is a topical, nonaqueous scrub that lists magnesium sulfate (commonly known as Epsom salt) as the second ingredient. Massaging it over wet skin (as the directions indicate) causes an exothermic (heat) reaction. Essentially, heat is released, and you’ll feel an intense warming sensation that gets stronger as the product is massaged over skin. The heat doesn’t really benefit skin, though I am sure some consumers would comment their skin feels energized or invigorated as a result. The result is not akin to a mini-peel as Olay alleges. The polyethylene beads exfoliate skin, but the glycolic acid is useless because the magnesium sulfate keeps this product alkaline, and AHAs need an acidic pH to exfoliate. Still, although it’s somewhat gimmicky, this is an okay scrub for all skin types, except very oily.
Source: Paula Begoun