When it comes to acids in skincare, there is no shortage of opinions to choose from. So when you’re trying to find the best one for your skin concerns and goals, it can be hard to figure out which one you should use.

The most important thing to remember is that what works best for you might not for another person—and vice versa! 

That’s why it’s a good idea to understand how skincare acids work. That way, you can choose the right one for you. Allow us to guide you!

What are acids in skincare?

Chemistry lessons taught us acids are substances that have a pH below seven (neutral). But what exactly does that mean for your skin? It depends on the type of acid!

There are some things you should know before you start using acids on your skin.

How to use acids in skincare

Though acids can be super useful, you need to take some safety considerations into account:

1. You may want to patch-test an acid before applying to your full face.

2. Never exceed dosage recommendations.

3. If irritation occurs, reduce the frequency or stop using.

4. Consult with a licensed dermatology provider before use.

5. Increase use gradually over time as tolerated.

6. Be cautious when combining acids.

7. Some acids, like alpha-hydroxy acids (AHAs), cause UV sensitivity,¹ so always check the label.

Now let’s have a look at what skincare acids can do for you.

The top 9 skincare acids and how to wield their power

Find out how skincare acids are classified and the unique benefits and side effects of each one. 

Benefits of alpha hydroxy acids (AHAs) and how to use them

AHAs are some of the most popular acids for skincare. Why? Because they can help you get glowing skin!

Benefits: AHAs are excellent exfoliants, especially for dry skin, and can improve pigmentation problems, acne, and signs of aging.²

Mode of Action: AHAs help remove dead skin cells, increase water retention, and boost collagen production.³

Safety: AHAs may cause irritation and sun sensitivity,⁴ so be sure to wear sun protection and use them at night.

There are several different types of acids classified as AHAs: lactic acid, glycolic acid, mandelic acid, and more. So how are they different? Let’s take a closer look.

1. Lactic Acid

This alpha-hydroxy acid gets its name from milk, but it's also found in fermented veggies. Lactic acid is known to be hydrating so it can be a good option for dry skin. It's often recommended as an exfoliant to treat acne and reduce signs of aging.⁵

It’s found in night creams and cleansers—which you can use to improve skin texture—in concentrations of around 10% or less.⁶ You can also find it in peels.

2. Glycolic Acid

Glycolic acid is made from sugarcane. It's good for helping to treat acne and smoothing the skin, and you'll often find it in peels, but also in creams, gels and toners.⁷

Glycolic acid improves the skin’s appearance and may reduce the appearance of wrinkles. It’s also effective for treating sun spots.⁸ 

3. Mandelic Acid

Mandelic acid is an excellent option for sensitive and mature skin. It treats acne and hyperpigmentation, improving skin quality, elasticity, and firmness.⁹ When in a chemical peel, it delivers a similar level of effectiveness to salicylic acid and was better tolerated.¹⁰ 

You often find it in over-the-counter formulations of around 5-10%. 

4. Citric Acid

Naturally found in citrus fruits, citric acid’s distinguishing quality is its ability to increase collagen production and reduce sun spots.¹¹ 

Many citric acid products, such as Curology’s Cleanser and Moisturizer can be applied several times a week or even daily. In more concentrated products like peels you should check the instructions to find out how often to use them. 

Benefits of beta-hydroxy acids (BHAs) and how to use them 

BHAs are oil-soluble exfoliants. They enable deep penetration to unclog pores and remove impurities. The main BHA you’ll find in skincare formulations is salicylic acid. Let’s take a closer look at its benefits and possible side effects.

5. Salicylic Acid

Salicylic acid (SA), the main BHA is one of the most commonly used acids in skincare products. 

Benefits: SA is one of the best options for acne-prone skin. It's a potent anti-inflammatory, especially well suited to oily and blackhead-prone skin.¹²

Mode of Action: Similar to AHAs, BHAs help to exfoliate the top layer of dead skin cells, allowing them to slough off.  

Safety: BHAs are considered safe but can be drying, and may cause sun sensitivity.¹³

You can find 2% salicylic acid in Curology’s Acne Body Wash. 

Anti-aging acids

Aside from AHAs and BHAs, here are some extraordinary acids for skincare that you need to know about if you’re looking for anti-aging effects.

6. L-Ascorbic Acid

Benefits: Also called vitamin C, it has potent antioxidant properties and helps protect against sun damage, reduces dark spots, and increases collagen production.¹⁴

Mode of Action: Neutralizes free radicals which protects your cells' DNA from damage. It also decreases melanin production.¹⁵

Safety: If you have sensitive skin, you may experience some possible side effects.

Vitamin C’s effectiveness is proportional to the concentration, but only up to 20%.¹⁶ It’s often found in serums. To stop vitamin C from breaking down, keep it away from sunlight, heat, and air.

7. Hyaluronic Acid

Benefits: Hyaluronic acid is generally a great acid for aging skin. It helps reduce the appearance of wrinkles and hydrates the skin.

Mode of Action: Hyaluronic acid binds water into the skin, rehydrating on a deeper level.¹⁷

Safety: Side effects are rare and it is generally considered safe.¹⁸

Hyaluronic acid is a great addition to a moisturizing routine, especially those starting to show signs of aging. It’s usually found in moisturizing creams and cleansers.

8. Azelaic Acid

Benefits: If you suffer from rosacea, melasma and/or acne, azelaic acid could be the one for you.

Mode of Action: Naturally occurring in some whole grains, azelaic acid has anti-inflammatory and antibacterial properties and helps lighten dark spots.

Safety: Being an anti-inflammatory agent, azelaic acid typically causes few side effects, but occasionally causes irritation.¹⁹

You can find azelaic acid in varying strengths, some available by prescription only. It’s also used in combination with other acne treatments like benzoyl peroxide.²⁰

9. Kojic Acid

Benefits: Kojic acid could be a great choice for you if you suffer from dark spots, as it reduces hyperpigmentation and helps brighten the skin.²¹

Mode of Action: It inhibits melanin production, reducing the skin’s pigmentation.²²

Safety: While generally recognized as safe for use, some adverse effects such as irritation may occur.²³

Choosing the right acid in skincare

Need help deciding what acids will work best for your skin? Curology's got your back!

Get your personalized skincare routine with Curology

Get your personalized skincare routine with Curology

Start your skin quiz

By snapping a few selfies, and answering a short questionnaire about your skin, our expert team of healthcare professionals will set you up with a skincare routine catered to your specific concerns. For personalized skincare at your fingertips, get started with Curology with a 30-day trial*.

P.S. We did the homework so you don’t have to:

1. FDA. Alpha Hydroxy Acids. (2022, November 22).

2. Babilas, P., et al. Cosmetic and dermatologic use of alpha hydroxy acids. JDDG. (2012, May 11).

3. Babilas, P., et al. Cosmetic and dermatologic use of alpha hydroxy acids. JDDG. Ibid.

4. Tang, S.C. and Yang, J.H. Dual Effects of Alpha-Hydroxy Acids on the Skin. Molecules. (April 2018).

5. Abd Alsaheb, R.A., et al. Lactic acid applications in pharmaceutical and cosmeceutical industries. Journal of Chemical and Pharmaceutical Research (2015, n.d.).

6. FDA. Alpha Hydroxy Acids. Ibid.

7. Babilas, P., et al. Cosmetic and dermatologic use of alpha hydroxy acids. JDDG. Ibid.

8. Babilas, P., et al. Cosmetic and dermatologic use of alpha hydroxy acids. JDDG. Ibid.

9. Jacobs, S.W. and Culbertson, E.J. Effects of Topical Mandelic Acid Treatment on Facial Skin Viscoelasticity. Facial Plast Surg. (2018, December 4).

10. Dayal, S., et al. Comparative study of efficacy and safety of 45% mandelic acid versus 30% salicylic acid peels in mild-to-moderate acne vulgaris. J Cosmet Dermatol. (February 2020).

11. Greene, B., et al. Citric acid: An α and β hydroxyacid for antiaging. JAAD. (March 2005).

12. Moghimipour, E. Hydroxy Acids, the Most Widely Used Anti-aging Agents. Jundishapur J Nat Pharm Prod. (2012, January 4).

13. FDA. Beta Hydroxy Acids. (2022, February 25).

14. Al-Niaimi, F. and Chiang, N.Y.Z. Topical Vitamin C and the Skin: Mechanisms of Action and Clinical Applications. J Clin Aesthet Dermatol. (July 2017).

15. Telang, P.S. Vitamin C in dermatology. Indian Dermatol Online J. (April-June 2013).

16. Telang, P.S. Vitamin C in dermatology. Indian Dermatol Online J. Ibid.

17. Papakonstantinou, E., et al. Hyaluronic acid: A key molecule in skin aging. Dermato-Endocrinology. (July-August 2009).

18. Becker, L.C., et al. Final report of the safety assessment of hyaluronic acid, potassium hyaluronate, and sodium hyaluronate. Int J Toxicol. (July-August 2009).

19. Webster, G. Combination azelaic acid therapy for acne vulgaris. J. Am Acad Dermatol. (August 2000).

20. Webster, G. Combination azelaic acid therapy for acne vulgaris. J. Am Acad Dermatol. Ibid.

21. Saeedi, M., et al. Kojic acid applications in cosmetic and pharmaceutical preparations. Biomedicine & Pharmacotherapy. (February 2019).

22. Saeedi, M., et al. Kojic acid applications in cosmetic and pharmaceutical preparations. Biomedicine & Pharmacotherapy. Ibid.

23. Saeedi, M., et al. Kojic acid applications in cosmetic and pharmaceutical preparations. Biomedicine & Pharmacotherapy. Ibid.

Donna McIntyre is a board-certified nurse practitioner at Curology. She obtained her Master of Science in Nursing at MGH Institute of Health Professions in Boston, MA.

*Cancel at any time. Subject to consultation. Results may vary. 

Written by

Curology Team

Medically reviewed by

Donna McIntyre, NP-BC