Lactic Acid vs Glycolic Acid: Which is Right for You?

If you’ve found yourself in an Internet rabbit hole trying to better understand AHAs and which one is actually right for your skin type and concerns, welcome, you’ve finally arrived at the right location! 

AHAs, or Alpha Hydroxy Acids, have become a skincare staple in recent years, and for good reason. While research on these incredible chemical exfoliants has been abundant for years, a growing number of clinical studies have further cemented their reputation and validated their brilliance — the exfoliating heroes that can do it all, from skin brightening and smoothing to anti-ageing and acne support.

Yet, there are key differences between AHAs that are important to be aware of. In this guide, we’ll break down the two most popular AHAs — Glycolic Acid vs Lactic Acid — covering what they do, their benefits, limitations, and how to know which one is better suited to your skin and goals. Lactic Acid vs Glycolic Acid: Is one better than the other? Let’s get into it…

If you’re new to the world of skincare, you may have already found yourself feeling a little in over your head with words like “acids” and “AHAs.” So, let’s quickly get you up to speed…

Alpha Hydroxy Acids (AHAs) are a group of acids that are used to chemically exfoliate the skin. When you think of “facial exfoliation,” you may associate it with physical or mechanical exfoliation, a method that uses pressure and motion to slough away dead skin cells (i.e., think a granule facial scrub or Dr Tanya's NuSonic exfoliating device). 

However, chemical exfoliation works differently, dissolving the glue that binds dead skin cells on the surface of the skin. In doing so, it allows them to easily slough off the skin. Among AHAs, the best-researched and most well-known are Glycolic Acid and Lactic Acid.

[Read Full Article: The Guide to Modern Exfoliation]

Lactic Acid gently exfoliates and hydrates the skin. Among the AHA family, Lactic Acid is generally considered one of the gentlest options, making it a great choice for chemical exfoliant beginners and people with sensitive or mature skin.

Fun fact: Lactic Acid is naturally found in sour milk and fermented foods. However, in today’s skincare products, it’s often made in a laboratory to ensure consistency and quality control.

What does Lactic Acid do for the skin? This incredible ingredient boasts an impressive list of benefits. Let’s take a look at a few of the most common ones:

• Hydrates the skin: Lactic Acid is unique among AHAs in that it exfoliates while also hydrating. Lactic Acid is a humectant, meaning it draws moisture from the environment into your skin, helping to maintain the health of your skin barrier.
• Brightens & Evens Skin Tone: By increasing the rate of skin cell turnover, Lactic Acid — like other AHAs — helps to shed dead, pigmented skin cells from the outer layer faster than the natural skin cycle. As a result, brighter, fresher skin cells can emerge, improving your complexion and tone. Secondly, Lactic Acid is suggested to help fade dark spots and PIH over time.
• Supports anti-ageing: Lactic Acid can help achieve younger-looking skin with consistent use. Firstly, as we already know, chemical exfoliants remove dead skin cells from the outer layer, thereby speeding up skin cell turnover. Secondly, Lactic Acid also hydrates the skin, which gives the appearance of plumper, smoother skin (while dehydrated skin accentuates fine lines and wrinkles).
• Gentle on the skin: Lactic Acid is suitable for most skin types, particularly sensitive/reactive and mature skin.

Lactic Acid consists of larger molecules, particularly when compared to Glycolic Acid’s remarkably small molecular size. While in many instances its size has benefits (i.e., it’s gentle and well tolerated by many skin types), the downside is that it is slower to absorb and won’t penetrate as deeply, so a slow and steady approach is needed to achieve results. Secondly, despite its gentle nature, it can still cause irritation if used incorrectly or too frequently, as it is an active ingredient.

Like Lactic Acid, Glycolic Acid is also part of the Alpha-Hydroxy Acid (AHA) family. Yet, unlike Lactic Acid, this adored ingredient is derived from sugarcane.

What makes Glycolic Acid most unique — especially when compared to Lactic Acid — is its small molecular weight. In fact, it is the smallest molecule of the entire AHA family. 

But what exactly does this mean in the world of skincare? The smaller the molecule, the deeper and more quickly it can penetrate the skin. While most AHAs focus on dissolving and loosening the bonds that bind dead skin cells together on the skin’s surface, Glycolic Acid can work beneath the surface to offer additional benefits, making it a great choice for those with oily and acne-prone skin.

Owing to its size and nature, Glycolic Acid boasts an impressive, versatile list of benefits that address many skin concerns and skin types. Wondering about Glycolic Acid uses for skin? Let’s take a closer look at a few of the key benefits and what it’s commonly used for:

• Faster Results: One clear advantage it has over Lactic Acid is its speed of action. While Lactic Acid is a gentle option that requires patience, Glycolic Acid is stronger and works more quickly.
• Smooths & Brightens Skin: Much like Lactic Acid, Glycolic Acid is widely adored for its chemical exfoliation benefits, which dissolve the bonds that hold dead skin together, helping reveal fresh, bright, and smooth skin cells that improve the texture and complexion of your skin.  
• Improves the efficacy of other skincare products: As it exfoliates the skin and unclogs pores, it can enhance the absorption of other products, allowing them to penetrate deeper and work more effectively.
• Supports acne-prone skin: Glycolic Acid can help in several unique ways. Firstly, owing to its deeper penetration and exfoliation benefits, it can help to clear blocked pores. It’s also regularly used to help correct uneven skin tone, particularly post-inflammatory hyperpigmentation caused by acne scarring/dark spots. However, as always, we recommend seeking expert advice from your dermatologist before trying any new products, especially on acne-prone skin.
• Supports anti-ageing: There are a couple of key ways Glycolic Acid is suggested to help slow the ageing clock. Firstly, studies have found a correlation between Glycolic Acid treatments and increased collagen production and fibroblast proliferation, which help keep our skin looking plump, smooth, and healthy. Secondly, speeding up skin cell turnover through chemical exfoliation helps to keep fresh, healthy cells at the surface, giving the appearance of younger-looking skin. However, while Glycolic Acid can help with fine lines, it is not recommended for more mature skin due to potential dryness and irritation.

While Glycolic Acid offers many benefits, it isn’t suitable for all skin types and concerns. Glycolic Acid can cause irritation, especially to those with sensitive skin. Secondly, it also makes your skin sensitive to the sun, meaning if you plan to incorporate it into your daily skincare ritual, you’ll need to always follow it up with sunscreen (which should be a non-negotiable part of your routine anyway!).

People with sensitive or dry skin will likely want to avoid Glycolic Acid, as it can worsen dryness. It’s definitely worth seeking guidance from your dermatologist before adding this one to your skincare ritual.

To put it simply, what sets Glycolic Acid and Lactic Acid apart is their molecular size. Lactic Acid consists of larger molecules, meaning it works more slowly and gently on the skin. However, Glycolic Acid has much smaller molecules, meaning it can penetrate the skin more deeply and deliver results faster.

Despite Glycolic Acid and Lactic Acid falling into the same family, it’s best to think of them as cousins, not twins. While they certainly share some benefits and similarities, there are also several key factors that set them apart. Here’s a quick snapshot to better understand how each looks on paper:

If you have specific skincare concerns in mind, it’s worth understanding the key differences between Glycolic and Lactic Acids and which may be more suited and better tolerated by your skin. Let’s take a closer look at lactic acid vs glycolic acid for specific skin concerns:

This one can be a little tricky to answer as there is a lot more that comes into play than just one’s skin type (i.e., the specific concerns they’re wanting to treat). However, the following may help you understand which option is naturally better suited to your skin type, or which may cause irritation. As always, we recommend consulting your dermatologist before starting any new skincare rituals.

Still not sure whether you should buy Glycolic Acid cream or Lactic Acid cream? You're not alone — and honestly, there's no single right answer. Both are excellent options, each with its own strengths depending on your skin type and concerns. That said, there are a few key things worth considering before you decide:

Glycolic Acid has more clinical studies under its belt. Don’t get us wrong, Lactic Acid still has a lot of research behind it, just not quite to the extent of Glycolic Acid. If your skincare decisions are largely dictated by clinical evidence, it’s worth considering this.

All of the above aside, a product’s results are only as good as its formulation. What exactly does this mean? Not all Glycolic Acid or Lactic Acid products are created equal.
When choosing a specific product, it’s important to consider the product’s concentration, pH level, other ingredients in the product (i.e., ceramides and hyaluronic acid may help counteract any irritation caused by glycolic acid), and the type of product and how long it will interact with the skin for (i.e., toner, serum, peel, etc.)

While all skin is unique and requires a personalised approach, the following general rule may help you decipher which acid is most suitable for you:

• Lactic Acid is better suited to sensitive/reactive, dry, and mature skin. It’s also generally the better option if you’re new to AHAs owing to its gentle nature.
• Glycolic Acid is better suited to oily, acne-prone, textured, pigmented, and ageing skin owing to its deeper penetration and faster results.