AHAs For Skin: What They Are And How They Work

AHAs For Skin: What They Are And How They Work


AHA, or Alpha Hydroxy Acid, is a popular exfoliant used in various skincare products. An AHA is a type of water-soluble Acid that is commonly derived from sugary fruits. These acids gently peep away dead cells from the surface of the skin to allow better cell turnover, leaving your skin with an even tone and a smooth texture. 

History Of AHA

AHA is one of the two popular types of hydroxy acids used in skincare, the other being BHA or Beta Hydroxy Acids. There is a long history of use of hydroxy acids to promote healthy and radiant skin even before the actual chemical composition was discovered. 

In Egypt, sour milk baths were standard to improve the texture of the skin. During the reign of Louis XIV, French women often washed their faces with old wine to make the skin feel refreshed and radiant. Many traditional skincare preparations use honey, yoghurt and fruit for the same benefits. These fruit acids or hydroxy acids were known for their active ingredients that gave the skin an instant glow by peeling away dead cells. Fermented grapes, sugarcane and honey, were the earliest forms of alpha hydroxy acids used in traditional skincare remedies. 

Before AHAs were incorporated into skincare formulations in modern dermatology, they were originally used for chemical skin peels. Although the complete mechanism of AHA on the skin remains unknown, these acids' ability to moisturise the outer layer of the skin while exfoliating it gently makes them a common ingredient in various skin care products. 

Properties Of AHA

Alpha Hydroxy Acids have specific properties that help improve the way your skin looks and feels. The most important skincare properties of AHA are as follows: 

  • Exfoliant: AHAs are also known to promote keratolysis. This is the breakdown of the glue between the skin cells to gently remove the outer layer of the skin to improve cell turnover. 
  • Anti-ageing: AHA can remove fine lines and wrinkles by improving skin cell regeneration. 
  • Anti-inflammatory agent: The anti-inflammatory properties of AHA help improve blood flow to the skin, giving it a better complexion. 
  • Antioxidant: Studies have shown that the antioxidant properties of AHA also help prevent any damage caused by harmful UV rays. 
  • Humectant: AHAs are potent in retaining moisture in the skin. This is because they can absorb water molecules from the environment and lock them into the skin. 

Sources Of AHA

As mentioned before, AHAs or Alpha Hydroxy Acids are commonly derived from fruit acids. They are found in a higher concentration in fermented foods like sour yoghurt or wine as well. Some of the best known natural sources of AHA are: 

  • Apples 
  • Sugarcane 
  • Honey 
  • Yoghurt 
  • Lemon 
  • Grapefruit 
  • Papaya 

Most fresh fruits are a good source of AHA and can be used in natural skin care remedies like home-made face masks. 

Different Types Of AHA

Six types of AHAs are used in skincare products: 

  • Glycolic Acid 
  • Lactic Acid 
  • Malic Acid
  • Citric Acid 
  • Tartaric Acid 
  • Mandelic Acid 

Differences Between Different Types Of These Ingredients

Each type of AHA has unique properties that affect its usage in skincare products. Here are some details to help you understand the difference between each of them and which one is best suited for your skin-related issues: 

Glycolic Acid

Among all the AHAs, Glycolic Acid is used in skincare products most often. This is because it is also the most well researched AHA along with Lactic Acid. 

Glycolic Acid stands out because of its size. The smaller molecules allow it to penetrate the outermost layer of built-up skin cells to remove them effectively. It also hydrates the skin naturally and improves skin ability to hold moisture for an extended period of time. 

Lactic Acid 

This AHA has all the properties of Glycolic Acid. The only difference is the time it takes to show results. Glycolic Acid acts faster than lactic Acid, making it more popular in skincare products. Since lactic acid molecules are larger, the ability to penetrate the outermost skin layer is reduced slightly.  

Malic Acid 

This is a type of AHA that is found in apples. The synthetic version of malic Acid is used in skincare products for maximum benefits. While malic Acid is larger than lactic and glycolic acids in terms of molecule size, it retains AHAs' exfoliant properties. However, malic Acid is a more potent antioxidant that makes it an excellent supporting ingredient in products led by lactic Acid or Glycolic Acid. This gives a multi-layered exfoliating effect for more radiant and glowing skin. 

Tartaric Acid 

The molecules of tartaric Acid are twice the size of glycolic Acid. This AHA is found in grapes. While Tartaric Acid provides notable exfoliation, it is better known for its ability to maintain the skin's natural pH range. This is why tartaric Acid is used along with other AHAs to improve the effect they have on the skin. Tartaric Acid, along with other AHAs, is best for targeted exfoliation.  

Citric Acid 

Citric Acid is found in various fruits and is readily available. It acts as an exfoliant only when used in large quantities. However, it has a naturally lower pH of 2.2, making it more likely to irritate the skin. Citric Acid is used in small quantities in skincare products to help improve the antioxidant effect. It can also balance the pH of the product itself, making it more effective.  

Mandelic Acid 

This is one of the least used types of AHA when it comes to skincare. One prominent reason is the lack of research on Mandelic Acid. It is also the largest of all AHAs, making it slower in penetrating the layers of the skin. This property is beneficial for those who have sensitive skin. Mandelic Acid is also known to prompt oil production in the skin. This is an excellent property for those who struggle with chronic skin dryness. 

Benefits Of AHA

AHA, whether used in its natural or synthetic form, has several benefits: 

  • It purifies the skin.
  • Fine lines are visibly reduced. 
  • Cell turnover improves 
  • Collagen production improves 
  • Helps treat acne 
  • Skin pigmentation is reduced. 

How AHA Functions For Each Skincare Benefit

The various properties of AHA or Alpha Hydroxy Acids provide the benefits mentioned above. Here is a detailed understanding of the various functions of AHA that are responsible for its popularity as a skincare ingredient: 

  • It purifies the skin: A common reason for including AHA as part of a skincare routine is chemical exfoliation. These acids break down the glue between the outer layer of dead skin cells, gently peeling it off to reveal newer, fresher skin. Although chemical exfoliation sounds like harsh skin treatment, it is gentler in comparison to using a scrub which can cause extreme skin irritation as you rub it over your skin several times. 
  • Fine lines are visibly reduced: When you age, the cell turnover of the skin also slows down. Because the skin doesn't shed the dead cells fast, they tend to accumulate on the surface, making skin look dull and increasing the appearance of wrinkles and fine lines. AHA clears this layer of dead skin cells, improving texture and removing minor imperfections almost instantly. Of course, deep-set wrinkles take a longer time to reduce. Additionally, AHAs do not strip the skin of moisture, retaining a supple and soft texture. 
  • Cell turnover improves: The cells of the body are bound together by a glue-like substance. This is also true for the keratinocytes or the skin cells. AHAs, through a process called keratolysis, unbind the dead cells, causing them to peel off gently. As the dead skin cells are shed, newer ones appear faster to replace them. As a result, overall cell turnover improves, making your skin look younger and more radiant. 
  • Collagen production improves:  Repeated use of AHA boosts collagen production. Collagen is a type of protein that is responsible for maintaining the tightness of the skin. With age, these proteins break down, leaving the skin sagging and wrinkled. Harmful free radicals accelerate this process. Glycolic Acid, which is one of the most popular AHAs used in skincare, has specific receptors that stimulate collagen production to keep your skin looking younger for longer. 
  • Help treat acne: Although BHAs are most recommended for acne, AHAs also have several benefits. Acne is usually the result of excessive sebum production, dead skin cell build-up and bacterial infection. The exfoliating properties of AHA help remove this dirt and gunk that clogs pores and even reduces the skin's oil production. As a result, acne is kept at bay. 
  • Skin pigmentation is reduced: With improved cell turnover, any pigmentation in the skin caused by acne scars, sun damage, pollution or several other factors is visibly reduced. Dead cells can store added pigments for several weeks, making the skin look patchy. When these cells are removed regularly, hyperpigmentation is reduced. 

What Skin Type Is AHA Used For And Why?

AHAs are considered safe for almost all skin types. They are gentle in their exfoliating action, causing negligible adverse effects. 

However, in the case of extremely oily skin, BHAs are a better option. AHAs are mostly recommended for skin that is sun-damaged and has surface issues like acne. They act best when applied on normal to dry skin. This is because they also hold and lock in some moisture on the surface of the skin. They can also be used on oily skin at regular intervals to remove any dirt or debris in the pores and reduce the activity of the sebaceous glands. 

What time of the day should this be used? 

AHAs can be used during the day or at night. If you wish to use both BHAs and AHAs on your skin, it is recommended that you use them on alternate days or use one with your daytime routine and the other with your nighttime routine. 

The application depends on the product that you are using. Some products that use AHA maybe night time serums while others may be masks or creams suitable for day time use. 

What quantity is suitable to use to show results?

Apply 3-4 drops of AHA on the skin and gently massage the face and neck to exfoliate and remove the outer layer of dead skin cells. 

Duration of usage for results

With AHAs, the results are almost instantaneous. Since they act as a chemical peel, you will notice that the skin becomes softer to touch in the very first application. For visible reduction of fine lines and wrinkles, using AHAs regularly for 4-8 weeks is recommended. 

What skin types are this ingredient not suitable for and why? 

AHAs are not suitable for sensitive skin as they may cause allergic reaction or redness and swelling. You must also not use these acids on the skin with conditions like rosacea. Because it breaks down the cells' walls to cause the exfoliating action, it can irritate very sensitive skin. Additionally, being acidic, the skin's pH may also be altered, leading to irritation of overly sensitive skin. 

Combinations And Conflicts

What other Ingredients can White Willow Extract Be Used With?

AHA, when combined with certain skincare ingredients, can provide added benefits. Some of the most recommended combinations for AHA are: 

  • AHA and Hyaluronic Acid: Hyaluronic Acid is a humectant. This means that it retains moisture in the skin, preventing any irritation after the exfoliating action of AHAs. Although AHAs do not extract as much moisture from the skin's surface as BHAs, it is recommended that you use a hydrating ingredient like Hyaluronic Acid or aloe vera along with it for best results. 
  • AHA and SPF: Since AHA tends to peel off the outer skin layer, it can cause sun sensitivity. Using an SPF and AHA will prevent any sun damage and keep your skin protected for longer. 

What ingredients should not be used in combinations/ succession with AHA?

Avoid the following combinations with AHA to prevent any damage to your skin: 

  • AHA and retinol: Retinol is also a powerful exfoliant. When combined with AHA, it can cause chronic skin dryness, increasing the appearance of fine lines or wrinkles. Additionally, a combination of AHA and retinol can irritate the skin, causing rashes or redness. 
  • AHA and vitamin C: Both these ingredients are acidic in nature. However, Vitamin C is pH sensitive. When used with AHA, its pH levels are altered, rendering it useless for the skin. The antioxidant property of vitamin C diminishes considerably when used with AHA. This combination can also result in skin irritation, especially if you are Vitamin C sensitive. 
  • AHA and niacinamide: Niacinamide, a type of B vitamin, can alter the pH level of AHAs. This reduces the absorption of the AHA in the skin. With AHAs like lactic Acid that already have larger molecules, mixing them with Niacinamide negates all their potent benefits. 


AHA is used in a variety of product formats. It is primarily used as a face serum for its chemical skin peeling effects. It can also be used in masks, lotions, exfoliating face washes, cleansers and toners along with other hydrating ingredients for improved daytime and nighttime skincare routines.

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Biocule has strict sourcing guidelines and relies on peer-reviewed studies, academic research institutions, and medical associations. We avoid using tertiary references. You can learn more about how we ensure our content is accurate and current by reading our editorial policy.

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