Pas71 is curious about Curel: I read an ad for Curel’s Ultra Healing Lotion, which claims to give you “more moisture where you need it and less where you don’t.” Supposedly it works by making the lotion positively charged so that it is attracted to the negative charge of dry skin. Is this a great new way to moisturize or just another product cashing in on the “positive ion” trend?

The Left Brain responds:
Curel makes an interesting claim that is based on a bit of real science.

Ionic Moisture

Here’s the real science: Skin and hair protein do develop a slight negative charge when they are damaged. It’s also true that positively charged ions are attracted to negative charges. (Think of how a magnet works.) Looking at the ingredients in Curel I see that in addition to standard moisturizing ingredients like glycerin and petrolatum, it also contains something called Behentrimonium Chloride. This is a cationic (meaning positively charged) conditioning agent. It’s typically used in hair conditioners, but in theory it would be attracted to negatively charged, damaged areas of skin.

Real world

However, theory doesn’t always reflect reality. In reality, moisturizers work by forming a film on top of the skin that prevents water from evaporating. It’s not like one ingredient is going to migrate across your skin to magically reach the damaged spots. Just because a lotion contains cationic ingredients doesn’t necessarily make it moisturize better. Curel Ultra Healing Lotion appears to be a very good moisturizer but I think this claim is more marketing hype than moisturizing breakthrough.