Lactic vs. Glycolic Acid: What’s the Difference?

When it comes to skincare ingredients, the term “acid” comes up repeatedly. While these ingredients are all in the same family, they each have a very different and unique role in your skincare routine. The two compounds we’ll be comparing today are lactic vs. glycolic acid. 

Both of these ingredients are alpha hydroxy acids (or AHAs) found in face serums and other products to help resurface your skin for a smoother, more radiant look. Depending on your skin’s unique needs, one might be a better fit for your complexion than the other. 

That’s why we’re providing you with this guide. Understanding how these two powerhouse ingredients work and where they shine is the first step to building a routine that really works for your skin. Let’s break down the difference between glycolic acid and lactic acid, and how to use them wisely. 



Key takeaways

• Glycolic acid is more potent and works quickly to improve the look of texture and dullness—best for resilient or oily skin types. 



• The main difference lies in molecular size and strength: glycolic acid acts faster but may cause irritation; lactic acid works more slowly with added hydration benefits. 



• You can use both acids together, but it’s important to introduce them gradually and always wear SPF. 



• Choosing between lactic vs. glycolic acid depends on your skin’s sensitivity level and what kind of visible results you’re looking for. 



What is lactic acid?

Lactic acid is one of the gentler exfoliating acids in the AHA family, and it’s made for refreshing your skin without the sting. It’s derived from sugar (yes, really!) and works by dissolving the bonds that hold dull, dead cells on the skin’s top layer. The result is skin that feels softer and glows just slightly brighter. 

Because lactic acid has a larger molecule size than glycolic acid, it doesn’t absorb as quickly, making it a favorite for those with delicate or easily reactive skin. So you’ll get the smooth, soft skin you’re after without any harshness.  



What is glycolic acid?

Glycolic acid is the overachiever of the AHA world. Known for its ultra-fine molecular size, it can work quickly on the skin’s surface—gently loosening dead skin cells to reveal a more luminous, even-looking complexion. It’s especially popular for smoothing texture and reducing the look of dark spots over time. 

Because glycolic acid is more potent than lactic acid, it can be a game-changer for those with thicker or more resilient skin types. However, the same potency may make it a bit too intense for sensitive skin, so a patch test is always a smart move. 



Glycolic vs. Lactic acid: What are the differences?

Understanding the differences in lactic acid vs. glycolic acid can save you from significant skin damage. Let’s take a closer look at some of the things that set them apart.  





Potency and absorption

One of the biggest distinctions between the two is molecular size. Glycolic acid has a smaller molecular structure, which means it works more quickly on the skin's surface. It’s often the go-to for people looking to visibly improve skin texture or brighten a dull complexion. But with great power comes a higher chance of sensitivity. If your skin tends to overreact or feel dry easily, glycolic acid might be a bit much. 



Gentleness and hydration

On the flip side, lactic acid has a larger molecular size, so it doesn’t absorb as rapidly. That’s actually a plus for sensitive or dry skin types. It exfoliates more gently, helping to reveal smoother-looking skin without the tingle. As a bonus, lactic acid is also an effective humectant—helping attract moisture and leaving skin feeling soft and hydrated by binding water to skin cells. 

Choosing lactic acid or glycolic acid all comes down to what your skin needs. If you’re newer to exfoliants, have dry or reactive skin, or just want a gentle glow, lactic acid might be your match. If your skin is more resilient and you’re chasing a more visible brightening effect, glycolic acid could be the one. 

The good news is you don’t necessarily have to decide between one or the other. Some face skincare products combine both acids at balanced concentrations, giving you the benefits of each without overdoing it. 

Can I use glycolic acid with lactic acid?

You can use glycolic acid and lactic acid together, but there are a few things to keep in mind so you don’t get yourself into trouble. Both acids are exfoliants, so layering them too frequently or in high concentrations can lead to over-exfoliation. This can show up as dryness, redness, or irritation. 

If your skin is resilient and already used to chemical exfoliants, using the two together—either in a combo product or spaced out across your routine—can offer a glow-boosting effect. Lactic acid hydrates while gently smoothing, while glycolic acid helps refine texture and enhance visible brightness. Together, they can create a more polished, luminous look. 

That said, moderation is key. Start slowly and always keep an eye on your skin. If you start to notice unevenness or irritation, it may be time to switch up your routine. Alternating application days may work better than using both at the same time, or you might choose to use one in the morning and the other at night. 

And no matter how you mix your AHAs, one golden rule always applies: sunscreen is non-negotiable. Acids can make skin more sensitive to sun exposure, so be sure to protect your glow with a broad-spectrum SPF during the day. 



Determining if lactic acid vs. glycolic acid is better for your skin

Choosing between lactic vs. glycolic acid really comes down to knowing your skin. If your skin is sensitive or new to exfoliating acids, lactic acid offers a gentler approach with added hydration. Glycolic acid, on the other hand, is ideal for those with more resilient skin looking to refine texture and brighten the overall look of their complexion. 

Whatever you choose, understanding the difference helps you use each one more confidently. Explore Clarins’ products with plant-based ingredients backed by science and take a step closer to creating a routine that works with your skin today. 



FAQ

Can I use glycolic acid with lactic acid?

You can, but it’s all about balance. Because both are exfoliants, using them together too often can lead to irritation, especially for sensitive skin. Start slowly, watch for any signs of dryness or redness, and always follow with SPF. 

What is lactic acid?

Lactic acid is an alpha hydroxy acid (AHA) known for gently exfoliating the skin while also attracting moisture. It’s ideal for dry or sensitive skin types that want a smoother, more radiant look without the sting. 

What is glycolic acid?

Glycolic acid is a fast-acting AHA that helps smooth skin texture and improve the look of dullness or uneven tone. Because of its small molecular size, it works quickly but can be a bit intense for more delicate skin types. 

Are glycolic acid and lactic acid the same?

Not quite. While both are AHAs and offer similar exfoliating benefits, they differ in strength and how they interact with your skin. Glycolic acid is stronger and more active, while lactic acid is gentler and more hydrating. 

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