Alpha hydroxy acid (AHA): Benefits, uses and side effects

For a brighter, smoother complexion, one group of acids may be helpful. Discover what they are, what exactly they can do and how to incorporate them into a skin care routine.

En este artículo:

• What is alpha hydroxy acid?
• Types of alpha hydroxy acids
• What does alpha hydroxy acid do?
• How to use alpha hydroxy acid
• Alpha hydroxy acid side effects

What is alpha hydroxy acid?

Alpha hydroxy acids (AHAs) are types of organic acids naturally present in sugarcane, fruit and sour milk.¹ Yes, we're talking lactic acid, glycolic acid and even citric acid - and they're in many cosmetics that help some people support their complexion. These potentially helpful acids come in many different forms including chemical peels, gels, lotions and serums.

Studies suggest that these acids stimulate cell renewal and can contribute to a reduction in the appearance of wrinkles and fine lines.²

Types of alpha hydroxy acids

Citric acid

Naturally found in citric fruits and juices, citric acid is used in personal care products to adjust the acidity of the skin, as well as promote skin turnover and stimulate cell growth.³

Glycolic acid

Glycolic acid, the smallest of the AHAs, has the ability to penetrate the skin. It may reduce the appearance of wrinkles, acne scarring and hyperpigmentation. It often comes as a chemical peel in skin care.⁴

Lactic acid

Lactic acid is used to help smooth and firm up the skin.⁵ Studies show that it can also improve the appearance of wrinkles and fine lines, while also potentially firming the skin.⁶

Malic acid

Malic acid adjusts pH levels in the skin.^7,8 It’s also used in exfoliants.⁹

Mandelic acid

A natural derivative of bitter almonds, mandelic acid gently exfoliates the skin when applied. It has antibacterial effects and can be used to reduce inflammation caused by acne and rosacea.¹⁰

Tartaric acid

Less well known than other AHAs, tartaric acid occurs naturally in grapes.¹¹ In the cosmetics world, it can be used to help lower the pH of the skin.¹²

What does alpha hydroxy acid do?

AHAs exfoliate dead skin cells from the skin's surface.¹³ This group frequently features in skin peels that can help reduce the appearance of acne, scars and possibly hyperpigmentation. These acids can also improve the appearance of wrinkles as they help thicken the skin.

AHAs can also increase the skin’s photosensitivity,¹⁴ which means that precautions need to be taken. Avoid direct sunlight and regularly apply a sunscreen with a sun-protection factor (SPF) of 30 or higher.¹⁵

How to use alpha hydroxy acid

The best way to introduce AHAs into a skin care routine is to speak with your dermatologist or other health care provider before starting. They can advise you on the optimal ways to use them. After you've brought a product home, always follow the instructions on the label. But there are some general ways to approach using AHAs.

When exfoliating, products containing AHAs should generally be applied to clean skin using small circular motions. Wash off with lukewarm - but not hot - water and moisturize immediately after to keep exfoliated skin hydrated.¹⁶

How often to exfoliate with an AHA depends on your skin type and sensitivity. Consult with your health care provider first. Consider experimenting with a small amount of an AHA and see how the skin reacts.¹⁷

For itchy or overly dry skin, immediately stop use of an AHA product and contact your health care provider.¹⁸

Use of AHAs can increase sensitivity of the skin to ultraviolet (UV) light. When using products containing AHA, avoid spending time in direct sunlight and regularly apply sunscreen.

Alpha hydroxy acid side effects

Always refer to the product label for directions and safety information. Common side effects after using AHA products include burning, itchiness, redness, skin sensitivity and swelling.¹⁹ If you experience adverse effects from using a product with AHA, stop using the product and contact your health care provider.

Este contenido es solo para fines informativos y no constituye un asesoramiento médico. Consult your health care provider before taking any vitamins or supplements and prior to beginning or changing any health care practices.