Lactic Acid for Skin Care: Benefits and Side Effects

Using lactic acid for skin care can help you have a smoother, brighter complexion. As a gentle alpha hydroxy acid (AHA), lactic acid removes dead skin cells, lightens dark spots, and improves the look of fine lines and wrinkles on all skin types, including sensitive skin.

What Is Lactic Acid?

Lactic acid is one of the most widely used AHAs. It is commonly found in over-the-counter skin care products as well as stronger professional peels and treatments.

Naturally occurring in dairy products, lactic acid gives yogurt and sour milk their tangy taste. Historically, dairy has been used worldwide to soften and enhance the skin.

Though milk baths remain popular, most lactic acid in skin care products today is synthetically made in laboratories.

What Does Lactic Acid Do for the Skin?

Lactic acid promotes smooth, healthy skin by speeding up cell turnover. It also enhances your skin’s natural ability to stay hydrated, known as the natural moisture factor.

This results in a brighter complexion with smoother, softer skin.

While more research is needed to understand how lactic acid supports skin health, the following are some of the benefits of using the AHA according to experts:

• Supports collagen to keep skin firm
• Helps clear pores
• Regulates skin hydration
• Helps clear or prevent acne
• Reduces dark patches from freckles, sunspots, and age spots (hyperpigmentation)

The benefits of lactic acid may also be tied to the fact that it is an effective antimicrobial. That means it can stop the growth of bacteria on skin, which helps control breakouts.

Lactic acid is also an antioxidant. This is important for skin health because this property may help minimize the effects of heavy metals found in water, which can damage your skin.

In addition, products with lactic acid have been shown to help with these skin disorders:

• Eczema: Lactic acid reduces itching and restores your skin’s barrier.
• Psoriasis: Lactic acid can soften and remove scales.

Possible Side Effects

While lactic acid is milder than some other alpha hydroxy acids, it remains a powerful treatment. Here are some possible side effects of using lactic acid on your skin.

Sun Sensitivity

Lactic acid is that it can make your skin more sensitive to the sun. As the acid sloughs away skin cells, it leaves your skin more likely to be damaged by ultraviolet light from the sun.

Some studies have suggested that sun sensitivity can last for four weeks after you’ve stopped using a lactic acid product or peel treatment—maybe even longer.

Use SPF 30 or higher sunscreen daily to protect your skin from sunburn and sun damage, even on cloudy days. If you don’t protect your skin, you could undo the benefits of lactic acid, like its ability to fade spots and soften wrinkles.

Skin Irritation

Lactic acid may also lead to skin irritation. Watch for symptoms such as:

• Redness
• Burning
• Peeling
• Dryness
• Itchy skin
• Swelling

You may have mild redness, burning, and itching when you first start using a lactic acid product. As long as it is not bad and goes away within an hour or so, it’s nothing to worry about.

However, if the redness, burning, and itching are moderate to severe, or if you have swelling or a rash, wash the product off immediately and do not use it again. Call your healthcare provider for advice on what to do for your skin.

Who Should Not Use Lactic Acid on Their Skin?

Lactic acid is the gentlest of alpha hydroxy acids. Most people can use it safely, including those who are pregnant. Still, some people should not use products with lactic acid.

If you have very sensitive skin, lactic acid can irritate it. Start with a product that only has a small percentage of lactic acid (e.g., 5%) and see how your skin reacts to it. If you notice any irritation, stop using the product.

If you use topical retinoids like Retin-A or Refissa, don’t add lactic acid to your skincare routine. These products are already exfoliating your skin, so if you also use a product with lactic acid, your skin could get too sensitive.

How to Use Lactic Acid on the Skin

Over-the-counter (OTC) lactic acid products come in concentrations up to 10%. A higher percentage is available via professional therapies, but higher is not always better since more concentrated products can irritate your skin.

Lactic acid is considered generally safe at lower concentrations. Start with a product that has about 5% lactic acid. Before applying a new product, first perform a test on a small area of your skin to check for any adverse reactions.

As long as your skin can handle it, you may be able to use the products daily. However, using them every few days should be enough to see results. It can take a few months, though, to see noticeable results.

Types of products with lactic acid include:

• Cleansers: Used at nightly, these are a good choice for sensitive skin because you rinse them off.
• Moisturizing creams: Apply these at night rather than during the day to minimize sun damage. Even so, you’ll still need to apply sunscreen every morning.
• At-home peels and masks: These can be used one to three times per week, depending on the product.
• Professional lactic acid peels: These are done at a spa, dermatologist, or cosmetic surgery office. With higher concentrations of lactic acid, these peels are a better choice if you have a specific issue to address, such as dark spots or blackhead removal.