With all the comings and goings of popular cosmetics ingredients, one natural option remains a mainstay for turning back the clock: alpha-hydroxy acids. They work.
Alpha-hydroxy acids—AHAs—include three kinds of acids that naturally occur in common foods: glycolic acid, lactic acid, and fruit acids. These light acids can exfoliate the skin, sweeping away the upper layer of dead skin cells and revealing the younger, smoother layer underneath. This can also stimulate new cell growth.
How do they work?
When we are young, it takes six to eight weeks for our skin cells to form in the basal (deeper) layer of the skin and eventually move toward the surface of the skin and then slough off. The constant turnover of cells keeps our skin looking smooth, wrinkle free, and vibrant in our teens and 20s. As we age, this process slows down. Our dead skin cells clump and build up on the surface, causing the skin to look dry, dull, and aged.
Exfoliating treatments that use AHAs can speed up cellular turnover. By clearing away the top layer of dead skin cells, they prompt the body to send a chemical signal to the skin's basal layer to rev up and get the skin cells turning over more quickly again.
The most potent of the AHAs is glycolic acid, which is found in sugarcane. The smaller size of the glycolic acid particles allows for better penetration into the skin. Glycolic acid is the most common AHA used in large-brand skin care products, and it can be concentrated to form a very effective in-office chemical peel. Try Pai's Copaiba Deep Cleanse AHA Mask ($60)
Lactic acid comes from milk and acts as a moisturizer and a gentle exfoliator. Women in ancient Egypt—including Cleopatra, according to legend—used to bathe in milk for its beautifying effects. Try Marie Veronique Daily Exfoliating Cleanser ($35)
Fruit acids include citric acid from citrus fruits. These are the easiest of the AHAs to use for DIY home masks and chemical peels. Try Juice Beauty Green Apple Peel Sensitive ($42)
Top tip: Look for products with an AHA concentration of 7 percent or higher for the best results. Doctors often prescribe AHAs at a concentration of 20 to 30 percent, but everyone's skin has a different tolerance for AHAs. Some people tolerate them well and benefit from a stronger concentration for the best results. Ideally, settle on a strength that produces some light initial flaking of the skin that resolves quickly and doesn't cause extended redness or irritation.
Interested in all-natural AHA treatments you can make and use at home? Here are two fun DIY ones to try:
DIY AHA mask
This mask doubles up on fruit acids from orange and lemon juices and lactic acid from yogurt. It also contains a healthy dose of the antioxidant vitamin C.
- 3 tablespoons orange juice
- 2 tablespoons lemon juice
- ¾ cup plain yogurt (unflavored and unsweetened)
- Mix the ingredients together with a fork until combined and apply the mixture to your face.
- Let the mask sit for 20 minutes or until dry.
- Rinse off with warm water. Your skin will feel softer and smoother. Repeat twice a week as desired for glowing skin.
DIY AHA exfoliating mask
The lactic acid in the milk will gently exfoliate your skin, and the cornstarch will soothe it. Lavender is a good essential oil to consider for this preparation due to its relaxing effects.
- 1 cup powdered whole milk
- ¼ cup cornstarch
- Several drops of the essential oil of your choice (lavender is a good one)
- Mix the ingredients together in a large bowl. Pour the mixture into the bath under warm running water.
- Sink in and feel like an Egyptian goddess!