---
title: "AHA (Alpha Hydroxy Acid) — Glossary | School of Dermatology"
description: "Learn what alpha hydroxy acids (AHAs) are, how they exfoliate the skin, and why they're used to improve texture, tone, and signs of aging."
lang: en
json-ld: |
  [
    {
      "@context": "https://schema.org",
      "@type": "DefinedTerm",
      "name": "AHA (Alpha Hydroxy Acid)",
      "description": "Alpha hydroxy acids are a group of water-soluble acids derived from fruits, milk, and sugar cane. The most common AHAs in skincare include glycolic acid (from sugar cane) and lactic acid (from milk). They work by loosening the bonds between dead skin cells on the surface of the skin, promoting gentle exfoliation and cell turnover. AHAs are particularly effective for improving skin texture, reducing the appearance of fine lines, evening out skin tone, and addressing sun damage. They also help the skin retain moisture. Because AHAs increase sun sensitivity, sunscreen is essential when using them. They are best suited for normal to dry skin types and are generally used at concentrations between 5% and 10% in at-home products.",
      "url": "https://schoolofdermatology.com/glossary/aha-alpha-hydroxy-acid",
      "inDefinedTermSet": {
        "@type": "DefinedTermSet",
        "name": "School of Dermatology Skincare Glossary",
        "url": "https://schoolofdermatology.com/glossary"
      }
    },
    {
      "@context": "https://schema.org",
      "@type": "BreadcrumbList",
      "itemListElement": [
        {
          "@type": "ListItem",
          "position": 1,
          "name": "Home",
          "item": "https://schoolofdermatology.com"
        },
        {
          "@type": "ListItem",
          "position": 2,
          "name": "Glossary",
          "item": "https://schoolofdermatology.com/glossary"
        },
        {
          "@type": "ListItem",
          "position": 3,
          "name": "AHA (Alpha Hydroxy Acid)",
          "item": "https://schoolofdermatology.com/glossary/aha-alpha-hydroxy-acid"
        }
      ]
    }
  ]
---

[![School of Dermatology](/assets/logo-AGZDufdq.svg)](/)

Articles

[Skin Types](/skin-types)

Tools

[Glossary](/glossary)

[Home](/)/ [Glossary](/glossary)/ AHA (Alpha Hydroxy Acid) 

Glossary 

# AHA (Alpha Hydroxy Acid)

AL-fuh hy-DROK-see AS-id 

## Definition

Alpha hydroxy acids are a group of water-soluble acids derived from fruits, milk, and sugar cane. The most common AHAs in skincare include glycolic acid (from sugar cane) and lactic acid (from milk). They work by loosening the bonds between dead skin cells on the surface of the skin, promoting gentle exfoliation and cell turnover. AHAs are particularly effective for improving skin texture, reducing the appearance of fine lines, evening out skin tone, and addressing sun damage. They also help the skin retain moisture. Because AHAs increase sun sensitivity, sunscreen is essential when using them. They are best suited for normal to dry skin types and are generally used at concentrations between 5% and 10% in at-home products.

## Related Terms

[Glycolic Acid](/glossary/glycolic-acid)[Lactic Acid](/glossary/lactic-acid)[Chemical Exfoliant](/glossary/chemical-exfoliant)[Exfoliation](/glossary/exfoliation)

Was this definition helpful?

In This Entry

[Definition](#definition)[Related Terms](#related-terms)

More "A" Terms

[Antioxidant](/glossary/antioxidant)[Astringent](/glossary/astringent)[Atopic Dermatitis](/glossary/atopic-dermatitis)

#### Ingredients

-   [Browse All](/topics/ingredients)

#### Treatments

-   [Browse All](/topics/treatments)

#### Skin Concerns

-   [Browse All](/topics/skin-concerns)

#### Light Therapy

-   [Browse All](/topics/light-therapy)

#### Skin Care

-   [Browse All](/topics/skin-care)

#### Hair Care

-   [Browse All](/topics/hair-care)

#### Resources

-   [Skincare Glossary](/glossary)
-   [All Articles](/articles)
-   [Contact Us](/contact)

© 2026 School of Dermatology. All rights reserved. For educational purposes only.

[Privacy Policy](/privacy-policy)[Terms of Service](/terms-of-service)[Disclaimer](/disclaimer)

![](https://bat.bing.com/action/0?ti=343074860&Ver=2&mid=77e5a43d-40b6-4dae-8d61-e866ef74c914&bo=1&sid=582ddda0aafb11f18ffe95d2b8958126&vid=582e1340aafb11f19e7e9dafc1e3c0eb&vids=0&msclkid=N&pi=918639831&lg=en-US&sw=800&sh=600&sc=24&nwd=1&tl=AHA%20\(Alpha%20Hydroxy%20Acid\)%20%E2%80%94%20Glossary%20%7C%20School%20of%20Dermatology&p=https%3A%2F%2Fderm-school-hub.lovable.app%2Fglossary%2Faha-alpha-hydroxy-acid&r=&lt=1010&evt=pageLoad&sv=2&cdb=AQAQ&rn=73613)

![](https://bat.bing.com/action/0?ti=343220809&Ver=2&mid=b1ad1376-3e44-4c1f-a729-582ead74d67d&bo=1&sid=582ddda0aafb11f18ffe95d2b8958126&vid=582e1340aafb11f19e7e9dafc1e3c0eb&vids=1&msclkid=N&pi=918639831&lg=en-US&sw=800&sh=600&sc=24&nwd=1&tl=AHA%20\(Alpha%20Hydroxy%20Acid\)%20%E2%80%94%20Glossary%20%7C%20School%20of%20Dermatology&p=https%3A%2F%2Fderm-school-hub.lovable.app%2Fglossary%2Faha-alpha-hydroxy-acid&r=&lt=1010&evt=pageLoad&sv=2&cdb=AQAQ&rn=481376)