You ever go to a restaurant, and when you sit down the waiter asks, “Do you want still or sparkling water?” And you say “Still please, thank you,” and then they bring out a bottle, crack it open, and charge you seven bucks? The check comes, and you realize you’ve been duped into paying more just because you didn’t understand what was being offered.

Retinol body creams are kind of like that.

In order to understand them, you need to sit down at the table already knowing the following:

1. The skin on your face is thinner than the skin on your body. If you think of your skin cells like a stack of crepes, the cells in your body skin would be twice as tall as those in your facial skin. (It varies by where exactly on the face and body you’re measuring, but the gist remains the same.)
2. Because it’s thicker, body skin is less sensitive to irritation. You know this already if you wash your body with Dr. Bronner’s and your face with Milky Jelly.
3. So not only can body skin handle stronger exfoliators, it kind of needs the extra oomph to get the job done.
4. The only form of vitamin A your skin cells know how to put to use is retinoic acid, which is either available by prescription (as tretinoin) or in very few OTC products (as adapalene).
5. And retinol, a derivative of retinoic acid, is 10 to 20 times weaker than the prescription stuff.

The retinol in a big bottle of body cream is going to be far more diluted than what you’ll find formulated for the face—Skinceuticals makes a full 1-percent retinol face cream, but a Paula’s Choice body version only has .1-percent. Once your skin converts that to retinoic acid, you’ll only be left with .01 to .005-percent of the active ingredient—way less than what’s in most facial products, and probably not enough for the thick skin on your body! To make up for it, most brands pump their retinol body creams up with antioxidants, rich butters, and acid exfoliators—which are great! But not retinol. And then they charge a skincare-as-bodycare premium. (That Paula’s Choice one is the cheapest you’ll find!)

Instead of doing that, read between the lines—tap water is free, and an OTC retinoid like the one from The Ordinary will cost you less than $10. Why not mix a little bit into your favorite body lotion and make your own retinoid body treatment? A gigantic, family-sized bottle of Gold Bond lotion is just 13 bucks, and the pair will last you a really long time even if you slather yourself in it a few times a week before sliding into bed.

There are very few, if any, clinical studies on retinol body creams, so this is all just hypothesis. Maybe sit this one out if you have super sensitive, eczema-prone skin or burn easily in the sun. But if you try it out, let us know—and always remember to use lots of SPF in the morning.

Photo via ITG