In this article:
Exfoliation is the process of cleansing the skin’s surface of dead skin cells, debris, bacteria, or oil. While your skin has some degree of natural exfoliation on its own, you can aid this process with the help of chemical or physical exfoliants.
Glycolic acid and lactic acid are two popular chemical exfoliants that belong to the alpha hydroxy acid (AHA) family. They help clear up built-up dirt and debris on the skin’s surface and give it a refreshed look. (1)
Note: It is essential to use sunscreen when you apply any acids – particularly AHAs – on your skin. They can make your skin ultrasensitive to the sun’s UV rays. (1)
Is It Safe to Use an Acid on Your Skin?
The AHAs used in skin care formulations are generally mild and do not cause skin peeling. However, they can make your skin sensitive to sunlight and should be avoided during the daytime.
Make sure to use sunscreen and try to limit sun exposure while using AHAs. Always use lower concentrations of the acid (around 2%) before moving on to higher concentrations.
For glycolic acid
Glycolic acid is effective in killing C. acnes bacteria in concentrations as low as 0.2%. Research suggests that it is most effective at a pH range of 3–3.5. (2)
For lactic acid
Lactic acid was found to be more effective at higher concentrations and lower pH ranges. Yet, it is recommended to start with a lower concentration if you are new to AHA use. (3)
If the alpha hydroxy acid is exfoliating your skin as it should, you may initially notice minor skin tingling or irritation. If you experience severe irritation, redness, or itching, it is advisable to discontinue use and consult a dermatologist for review. (1)
What’s the Difference Between Lactic Acid and Glycolic Acid?
Although glycolic acid and lactic acid are similar to some extent, they have a few key differences:
- Molecule size: Lactic acid has a larger molecule size than glycolic acid. Thus, glycolic acid can penetrate deeper into the skin and has better absorption capability. People with sensitive skin should choose lactic acid over glycolic acid due to the former’s inability to penetrate deep into the skin. (4)
- Speed of results: Due to its smaller size, glycolic acid provides deeper exfoliation and may give quicker results. On the other hand, lactic acid is gentler and might take longer to work. (5)
- Moisturizing benefits: Lactic acid has a higher moisturizing capacity. It can help your skin stay hydrated for longer. (6)
Research suggests that glycolic acid helps in deep exfoliation and is a more potent exfoliant than lactic acid. However, lactic acid is gentler on the skin and shows similar effects to glycolic acid in clinical trials. If you have sensitive skin, lactic acid should be a better option for you. (7)(8)
What Is Lactic Acid?
Commercial lactic acid is an organic acid made from the sugars present in milk. It is a colorless liquid and is similar to the lactic acid naturally found on the skin’s surface.
Lactic acid has potent hydrating properties (unlike other AHAs) and is mild on the skin. It helps increase collagen production and cell turnover (replacing old skin cells with new ones). It also helps bind water molecules to the skin cells and keeps the skin hydrated.
What Is Glycolic Acid?
Glycolic acid is another popular chemical exfoliant. It is the most powerful AHA used in skin care products and may not be tolerated well by sensitive or young skin.
It deeply exfoliates the skin by increasing cell turnover, deep penetration due to its small size and keratolytic (breaking down of skin cells) abilities, and increasing collagen content of the skin.
Glycolic acid is usually recommended for mature skin to help reduce fine lines and wrinkles. It can also be helpful in getting rid of acne scars. (10) Glycolic acid can help reduce hyperpigmentation, acne scars, and wrinkles and brighten the skin.
Can Lactic Acid and Glycolic Acid Be Used Together?
Yes, but only in products that contain both. Do not mix separate glycolic and lactic acid formulations.
Some products are formulated with both glycolic acid and lactic acid. However, using them may lead to overexfoliation and skin irritation. It is better to consult a dermatologist before using higher concentrations of AHAs on your skin.
Things to Remember When Using Lactic Acid and Glycolic Acid on the Skin
- Choose a skin care product that has both lactic acid and glycolic acid. Always check product formulations before use. (1)
- The US FDA has warned to look out for adverse reactions such as peeling, burns, and redness when using AHAs. Discontinue use immediately if you notice any of these. (1)
- Use lower concentrations of products to avoid these side effects. The ideal concentration may be less than 10%.
Note: Sun protection is essential while using AHAs. Also, if you are new to AHA use, always start with products that contain pH values around 4. Try to use lower concentrations (about 5% should be enough for daily use).
Which Acid Is Best for Which Skin Concerns?
Glycolic acid is usually recommended for aging skin or people with oily skin or acne scars. On the other hand, lactic acid is a good option for almost all skin types (including sensitive skin) as it is mild and has hydrating qualities.
Most-Asked Questions About Lactic Acid and Glycolic Acid for Skin
If I am new to acids, what should I start with – glycolic acid or lactic acid?
If you are new to AHAs, you can start by using lactic acid as it is milder on the skin and is a good hydrating agent. Start with lactic acid formulations that have lower concentrations (5%) before moving on to glycolic acid.
Can I use glycolic acid in the morning and lactic acid at night?
Always use glycolic acid at night as it can make your skin sensitive to sunlight during the daytime. Make sure to use sunscreen in the morning.
What can you not mix with glycolic acid?
Do not mix glycolic acid with vitamin C. Vitamin C, or citric acid, is also an AHA, and mixing it with glycolic or lactic acid can throw off the pH balance of the skin. It may even lead to redness or peeling.
Does lactic acid shrink pores?
Yes. Lactic acid can lead to the shrinkage of pores by gently exfoliating the skin and getting rid of debris and dead skin cells in enlarged pores.
Does glycolic acid lighten the skin?
No. Glycolic acid can reduce hyperpigmentation and acne scars to brighten your skin, but it will not lighten the skin.
What are some other AHAs other than lactic and glycolic acid?
Malic acid, tartaric acid, and citric acid are some other examples of AHAs other than lactic acid and glycolic acid.
Both lactic acid and glycolic acid can be good exfoliants for the skin. Choose the one most suited for your skin type and condition based on the information given above.
If you are unsure of your skin type, it may be a good idea to visit a dermatologist for proper assessment and guidance. Always perform a patch test before applying anything directly on your skin.