Alpha Hydroxy Acids

What are Alpha Hydroxy Acids?

Alpha hydroxy acids are also called AHAs. They are chemical compounds that are naturally occurring from plants and animals. They can also be synthetically made. Most AHAs in skin care are synthetically made. 

AHAs are popular additions to skin care for good reason. I’ve used them for over 30 years in my dermatology practice.

What are the different AHAs commonly used in skin care products?

• Glycolic acid (originally derived from sugar cane, the smallest molecule in the AHA class, and the best AHA for skin penetration)
• Lactic acid (originally from milk)
• Malic acid (originally from apples)
• Tartaric acid (originally from grapes)
• Citric acid (originally from citrus)

Most skin care products contain glycolic or lactic acid because they are definitely the most effective AHAs. The benefits of both are well studied.

What are the uses and benefits of AHA’s in skin care?

• AHA’s exfoliate the outer layer of skin, called the stratum corneum.

This brightens skin to a youthful glow. Glycolic acid is the best AHA for exfoliation.

• AHA’s treat dry skin by helping to bind water and stimulating skin to produce hyaluronic acid, which also binds water.

Both lactic acid and glycolic acid offer good benefit for dry skin.

• AHA’s brighten skin by a combination of exfoliation, hyaluronic acid production induction, and deep hydration.

Glycolic acid, with its small molecular size, is the most effective for this benefit.

• AHA’s can stimulate skin collagen renewal to reduce the appearance of scars, fine lines and wrinkles.

Glycolic acid is the best AHA for this. It’s ability to stimulate collagen renewal is well studied. Wrinkles, skin thinning, sagging, sallow and crepey skin all share a loss of collagen in the superficial dermis. All benefit from collagen renewal to help reverse these problems. To achieve this benefit, a glycolic acid product must have an acid pH and a concentration of glycolic acid over 10%.

• AHA's help reduceing skin hyperpigmentation from age spots, melasma and sun damage.

Glycolic acid is the best AHA for this. Pigmentation production is reduced and retained pigment in dead cells is sloughed, leading to improved uneven skin pigment. As with wrinkles, concentrations over 10% in acid pH products must be used.

• AHA's reduce acne lesions, especially blackheads.

AHAs are keratolytics, meaning they dissolve the 'glue' that holds dead cells together in clogged pores. When combined with salicylic acid (a beta hydroxy acid) they work even better, because salicylic acid is especially useful to penetrate down deep into oily pores.

• AHA's improve keratosis pilaris.

This genetic condition is characterized by follicular keratin plugs on the back of the arms, front of the thighs and even the back, facial cheeks and buttocks. Both glycolic acid and lactic acid work well to improve this condition.

• AHA's enhance penetration of other skin care ingredients.

All AHA’s help by virtue of their exfoliating benefits. Again, glycolic acid is well studied and highly effective owing to its small molecular size.

What are the side effects of AHA’s?

AHA’s can irritate sensitive skin. This can include redness, flaking and discomfort. If irritation continues, discoloration and even scarring may result. Exfoliation may also lead to sun sensitivity, and sun protection should be used with AHA skin treatment.

What is the best way to use AHA’s for skin care?

AHA’s are best used as daily products in creams, lotions or gels. Pick your product based on your skin type and product preference. Leave-on products are much more effective than rinse-off products such as cleansers. Strong AHA concentrations are also used professionally for chemical peels.

In my dermatology practice, the most popular AHA products include:

Glycolic Acid Anti-Wrinkle Face Cream. This hydrating, oil free cream comes in 10, 15 and 20% strength. It can be used day or night, and layers well with other products into your Dr. Bailey Complete Skin Care Routine for best results.

Glycolic Acid Face and Body Lotion is the go-to product for body care. The light-textured, hydrating and oil free lotion is made with 15% glycolic acid. It works especially well partnered with my Triple Action Exfoliating Cleanser and Salux Cloth in the Ultra-Fast Body Smoothing Triple Action Kit. Fight keratosis pilaris, uneven skin pigment from age spots, dry and flakey skin all in one routine. Get smooth skin with a dewy and youthful glow.

Ultimate Acne Solutions Kit combines glycolic acid with salicylic acid to clean deeply into pores. My Benzoyl Peroxide Acne Treatment Cream that is included in the kit penetrates more deeply with this product combination to help treat pimples and kill the P. acnes (now called C. acnes) bacteria that causes acne.

References

Bernstein, EF, et. al. (including Van Scott, E), Glycolic Acid Treatment Increases Type 1 Collagen mRNA and Hyaluronic Acid Content of Human Skin, Dermatologic Surgery 2001;27:429-433

Ditre CM et. al. (including Van Scott, E), Effects of alpha-hydroxy acids on photoaged skin; A pilot clinical, histologic, and ultrastructural study, Journal of the American Academy of Dermatology, 1996;34:187-195