One of our favorite blogs, Vivawoman, recently blogged about using yogurt as a facial exfoliant because it contains an Alpha Hydroxy Acid (AHA). According to her blog post, “I’m not sure what’s the concentration of AHA in the yogurt but the pH level is definitely under 5 and so most people can use it quite regularly” and that “there is no need to purchase cleansers or creams containing AHA because yogurt is a natural and viable option.” We thought this was an intriguing statement and decided to look at the facts behind lactic acid in yogurt and lotions.
Is yogurt a natural exfoliant?
First the good news: the pH of yogurt is about 4.5 which IS low enough for it to be effective as an exfoliant. However, according to this food science reference, yogurt only contains about about 0.9% free acid. Even if we assume that ALL the acid in yogurt is in the form of lactic acid (a common AHA) that’s still a very low concentration for an active exfoliant.
How much lactic acid do skin lotions contain?
In formulated products, AHAs are used at different levels depending on the intended effect. Regular “Over the counter” exfoliant lotions contain as little as as 5 to 10% AHA. Products formulated for professional application, like chemical peels, contain much higher levels (50 to 80%). As you can see, the amount of AHA in yogurt is only a fraction of what is needed for effective exfoliation.
The Beauty Brains bottom line
While it won’t hurt to use yogurt on your face it’s not an effective substitute for an exfoliant with 5 to 10 times as much lactic acid.
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Gee, I always heard that yogurt was good for your skin because the bacteria in it fought acne. Never heard anything about it having AHA.
In our experience, as distributors for private label skincare products, 50-80% is too high. Our clients, estheticians and consumers alike are using a professional product with 20%(sensitive skin) or 30%(oily, resistent). We also recommend a cleanser with both AHA and BHA. BHA is a able to stabilize free radicals and is retained on the skin to dissolve cellular debris. The time released exfoliation works for a while after the cleanser is rinsed off.
I’ve read that hydroxy acids, in order to be effective as an exfoliator, have to be in a product with pH less or equal pKa value, e.g. pKa for lactic acid is about 3.86, so apart from very low concentration of acid, pH of yogurt is a bit too high. Apparently it has something to do with unionized form of an active ingredient being better absorbed and more effective.
While not a super exfoliant, I’ve found yogurt is the perfect ingredient for a gentle exfoliating mask for my sensitive acne-prone skin. Whenever my face decides to rebel for whatever reason, I grab yogurt. It leaves my skin super soft and helps get rid of any flakiness.
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