Lactic Acid: What Is It, Skin Benefits, Cosmetic Uses & Side Effects

Fact-Checker: Priya Singh
This article was last updated on: May 21, 2023
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Ever found yourself flipping over a fancy tube of cream or a bottle of face wash, scanning the dizzying array of names listed under “ingredients”? Each of them seems to have stumbled out of a complex chemistry textbook, leaving you more puzzled than informed. Amid this baffling list, you’ve probably spotted “Lactic Acid”.

The name itself sounds like something you’d hear in a high school science lab, not an ingredient in your everyday skincare regimen. But the world of cosmetics is full of such surprises, and Lactic Acid is certainly one of them.

This article aims to unravel the enigma that is Lactic Acid. In the following sections, we will dig into its scientific origins, its functions in the world of cosmetics, and the benefits it brings to your skin. Not to forget, we will also shed light on any potential side effects.

What is Lactic Acid?

Lactic Acid, also known by its scientific moniker “Propanoic acid, 2-hydroxy-“, is a type of alpha hydroxy acid (AHA). It’s derived from sour milk but can also be produced synthetically for cosmetic applications. As an AHA, Lactic Acid is primarily used in skincare products for its exfoliating properties.

In the complex formulation of cosmetics, Lactic Acid serves several functions: it acts as a buffering agent, helps retain moisture as a humectant, and conditions the skin. It works by gently loosening the bonds between skin cells, allowing dead cells to be sloughed off more easily, revealing a fresher and brighter complexion.

Concentration levels in cosmetic products can vary. Typically, you can find Lactic Acid in concentrations ranging from 2% to 10%, depending on the product and its purpose. It is also available as a standalone product for those who prefer a more targeted application, although it is most commonly found as part of a broader formulation of ingredients.

Who Can Use Lactic Acid?

In general, Lactic Acid is suitable for a broad spectrum of skin types. It’s particularly well-suited to sensitive skin and those with a drier skin type, given its hydrating properties. However, everyone’s skin is unique, and individual tolerance to Lactic Acid can vary.

From a dietary perspective, Lactic Acid is safe for both vegans and vegetarians. Although it was originally discovered in sour milk, the Lactic Acid used in skincare is typically synthetic or plant-derived, making it an animal-friendly option.

Pregnant and breastfeeding women can generally use products containing Lactic Acid without concern. However, as with any skincare product, it is always advisable to consult with a healthcare professional or dermatologist if you’re pregnant or breastfeeding.

Lactic Acid Skin Benefits

Lactic Acid, as a prominent member of the alpha hydroxy acid family, offers a multitude of benefits for the skin. These include:

  • Exfoliation: As an exfoliant, Lactic Acid works by breaking down the ‘glue’ that holds dead skin cells together. By gently sloughing off these cells, it aids in revealing a smoother, more radiant complexion. Exfoliation also helps unclog pores and reduce the appearance of acne.
  • Hydration: Unlike many other exfoliants, Lactic Acid also serves as a humectant. This means it draws moisture into the skin, helping to hydrate and plump up the skin cells. This leads to a more moisturized and refreshed skin appearance.
  • Skin Conditioning: Beyond exfoliation and hydration, Lactic Acid is known for its skin conditioning properties. It helps to soften the skin, improve texture, and support overall skin health.

It’s important to note that these benefits aren’t permanent. Like with most skincare ingredients, consistent use is required to maintain the benefits of Lactic Acid. Once its application is stopped, your skin will gradually return to its pre-treatment state.

Lactic Acid’s Non-active Cosmetic Uses

Even when it’s not the star player, Lactic Acid still brings value to the cosmetic table. Its non-active roles in cosmetic formulations include:

  • Buffering Agent: Lactic Acid can regulate and maintain the pH of cosmetic products. A stable pH is crucial for the efficacy and safety of these products. This buffering capacity ensures that the product remains gentle on the skin while still performing effectively.
  • Humectant: Even when it’s not the primary active ingredient, Lactic Acid’s humectant properties play a crucial role in keeping the skin moisturized. It does this by attracting water molecules and locking them into the skin, providing a hydrating effect.
  • Skin Conditioning: In a non-active role, Lactic Acid contributes to the overall sensory experience of using a cosmetic product. It helps improve the texture and feel of the product, making it more pleasurable to use while conditioning the skin at the same time.

Lactic Acid Potential Side Effects

While Lactic Acid offers a multitude of skin benefits, it’s essential to understand that skin responses to any cosmetic ingredient can differ greatly from person to person. This variability arises from individual differences in skin type, skin sensitivity, and even lifestyle factors. As such, what might work wonders for one person could potentially cause discomfort for another. If you’re unsure about your skin type, you can refer to this resource to find your skin type.

Potential side effects of Lactic Acid may include:

  • Skin Irritation: Some people might experience temporary skin irritation, such as redness or a slight burning sensation. This is usually more common when first introducing Lactic Acid into a skincare routine or using it at higher concentrations.
  • Dryness: While Lactic Acid is known for its hydrating properties, in some cases, it can cause dryness, particularly if used excessively.
  • Photosensitivity: Like other AHAs, Lactic Acid can make the skin more sensitive to the sun. Therefore, always remember to use a broad-spectrum sunscreen when using products containing Lactic Acid.

If you experience any of these side effects while using Lactic Acid, it’s recommended to immediately stop using the product and consult a dermatologist or skincare professional. However, it’s important to remember that adverse reactions to Lactic Acid are relatively rare. Generally speaking, this ingredient is considered safe and effective when used appropriately.

When introducing any new cosmetic product, it’s always wise to perform a patch test to assess your skin’s tolerance. Doing so can prevent potential discomfort and adverse reactions on your entire face or body. You can refer to this comprehensive patch testing guide for detailed instructions. Taking these precautions will help ensure a positive and beneficial experience with Lactic Acid or any new skincare ingredient.

Comedogenic Rating

Lactic Acid has a low comedogenic rating of 1. This rating indicates that it’s unlikely to clog pores, a quality that makes it suitable for individuals with acne-prone skin. Its gentle exfoliating properties can actually help keep pores clear and reduce the occurrence of breakouts. However, as with any skincare ingredient, individual responses can vary, so it’s important to observe how your skin reacts to a product containing Lactic Acid.


Achieving success in skincare is a journey often paved with a degree of experimentation and trial and error. Every skin type is unique, and what works phenomenally for one person may not yield the same results for another. Lactic Acid, with its multi-faceted role in skincare, embodies this complexity.

This ingredient straddles active and non-active effects, providing immediate benefits like exfoliation and hydration while also working behind the scenes as a buffering agent and skin conditioner. These versatile characteristics might motivate a user to opt for products containing Lactic Acid over others.

Lactic Acid has steadily risen in popularity, primarily due to its beneficial effects and its suitability for various skin types. As more consumers strive to understand their skincare products, ingredients like Lactic Acid have come under the spotlight.

In terms of results, the timeframe can vary, but typically, improvements in skin texture and appearance might be noticeable after a few weeks of consistent use. However, factors such as the concentration of Lactic Acid in the product, your skin type, and how often you use the product will influence this.

To sum things up, in the realm of skincare, Lactic Acid stands out as a versatile and beneficial component, offering a unique blend of immediate and long-term benefits. Its appeal lies in its dual role, enhancing the skin’s health and appearance while contributing to the overall efficacy and texture of the products it’s a part of.

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