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Alpha- vs Beta-Hydroxy Acid: Which One Should You Use?

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Two popular ingredients commonly found in skin care products are alpha-hydroxy acids (AHAs) and beta-hydroxy acid (BHA). You’ve likely heard of them and know they’re important, but do you know the difference? If you’re like most individuals, you aren’t totally sure which one is right for your skin. So let us break it down for you.

First, the science: both AHAs and BHA are naturally derived organic compounds that contain a hydroxyl group and a carboxyl group. At the atomic level, the difference between AHAs and BHA is subtle, to say the least – AHAs have one carbon atom between their hydroxyl and carboxyl groups while BHA has two. In general terms, the most important difference is that AHAs are water-soluble, making them ideal for normal-to-dry skin types, while BHA is oil-soluble, and therefore perfect for oily and acne-prone skin. This isn’t a hard rule, however. AHAs and BHA have benefits for all skin types.

The most popular AHA is glycolic acid, which has been called by many the "holy grail" of skin care ingredients. Derived from sugar cane, glycolic acid has the smallest molecular size of any AHA, allowing it to penetrate more readily than other AHAs. Other AHAs include lactic acid (from milk), tartaric acid (from grapes), malic acid (from apples), citric acids (from citrus), mandelic acid (from almonds), and more. 

Salicylic acid is the common name for beta-hydroxy acid. Derived from willowbank, wintergreen and sweet birch, salicylic acid has properties similar to aspirin (acetylsalicylic acid), such an the ability to reduce inflammation.

The Case for Alpha- and Beta-Hydroxy Acids

As we age and after our skin has sustained damage – whether from sun exposure, hereditary skin conditions, medical conditions and the like – the skin’s natural exfoliation process becomes impaired. Instead of naturally sloughing off dead skin cells every 30 days, which is average for healthy skin, this regeneration process slows and dead cells build up on the surface of the skin. Because our skin must maintain a consistent thickness, as this dead skin layer (called “keratin”) becomes thickened, the dermis of our skin, where beneficial proteins like collagen and elastin are produced, becomes thinner and less able to keep our skin in optimal condition. To illustrate the point, the image below shows a slice of healthy skin on the left and that of unhealthy skin on the right, as characterized by a thickened keratin and unorganized skin layers.

AHAs and BHA work by dissolving part of the intercellular “cement” that holds together dead cells on the surface of our skin. By loosening their bonds, these cells can be easily sloughed off and the keratin thins, which, in turn, causes the dermis to thicken. This process is called  chemical exfoliation.

So Which One Should You Use? 

If you wish to reduce the signs of aging or sun damage, address dryness, control the occasional breakout and/or reduce skin sensitivity . . . an AHA is the right acid for you.

Do you have oily skin and/or frequent breakouts? If this describes you, you'll want to use BHA, which has the potential to penetrate deeper into pores to unclog them and can kill the bacteria that causes acne.

Keep in mind that, while one type might be more appropriate for your skin needs, many products, including  Lexli AloeGlyC, are formulated with both AHAs and BHA for optimal results. These products improve both signs of aging and acne, while helping to control skin's sebum (oil) levels.

As with any skin care product that promotes exfoliation, AHAs and BHA leave the skin more vulnerable to sun damage. For this reason, a sunscreen or moisturizer containing SPF 15 or higher should be applied daily when using products that contain these ingredients.

Have further questions about the use of AHAs and BHA? Leave us a comment!

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