This post may contain affiliate links, which means I may receive a small commission, at no cost to you, if you make a purchase.
Found yourself digging deep into the rabbit hole of AHAs and BHAs after facial scrubs didn’t do your skin any good?
You’re not alone; in fact, chemical exfoliants like salicylic acid and lactic acid are making waves online — and for good reason!
Instead of physically ridding your face of dead skin cells by rubbing your skin with grains or microbeads and in the process causing micro-tears (yikes!), salicylic acid and lactic acid dissolve dead skin cells from the top layer of your skin.
But before we dive deep into the world of chemical exfoliants, allow us to get you to the basics.
What Are AHAs and BHAs?
The idea of putting acids on your face may sound horrifying, but did you know that AHAs and BHAs have been used in skincare products for decades now?
Chances are that you may have seen AHAs and BHAs on your favorite skincare products’ ingredients list.
And in spite of being termed “chemical exfoliants,” these acids are actually derived from natural substances.
AHA stands for alpha hydroxy acid, while BHA stands for beta hydroxy acid. Both of these are families of chemical exfoliants, but each works differently and suits different skin types.
Alpha hydroxy acids are water soluble acids mostly extracted from naturally occurring sugars.
Being water soluble, AHAs lock in moisture but can’t penetrate deep into your pores. However, they effectively eat away at the “glue” that sticks dead skin cells together.
Meanwhile, beta hydroxy acids are derived from tree bark or leaves.
They are oil-soluble acids that penetrate deep into your skin, unclogging your pores of dirt, bacteria, and excess oil.
Since AHAs are mild exfoliants, dry and sensitive skin types will definitely love the gentle and moisturizing exfoliation that AHAs bring.
On the other hand, BHAs pamper oily and acne-prone skin types better with their antibacterial and declogging properties.
What Is Lactic Acid?
Now that you understand the differences between AHAs and BHAs, it’s time to get to know the most popular acids in each family.
Lactic acid — if the word “lactic” isn’t enough to give it away — is extracted from the sugars in fermented milk. Yes, milk. Remember the legends of Cleopatra bathing in milk?
You can find lactic acid in many products such as cleansers, gels, serums, moisturizers, and creams, including products that vaguely list AHAs among their ingredients but don’t specify which one.
Unlike fellow AHAs, lactic acid is composed of the largest molecules, making it the gentlest alpha hydroxy acid and the least irritating.
Benefits of lactic acid
Along with glycolic acid, lactic acid is one of the most popular AHAs out there due to the various scientifically proven skin benefits it offers. So yes, Cleopatra, Catherine Parr, and Elizabeth I were right!
Increases cell turnover
Like any AHA, lactic acid sloughs away dead skin cells to stimulate your skin’s process of producing fresh new cells.
According to Dr. Tiina Meder, dermatologist and founder of Meder Beauty Science, lactic acid enhances ceramide production, preventing skin dryness and locking in moisture as an AHA simultaneously.
Dead skin cells that block pores trigger acne breakouts. Without blocked pores, acne calms down.
Dead skin cells are what cause rough, dry, and dull skin.
Aside from promoting cell turnover, lactic acid also stimulates collagen production, reducing fine lines and resulting in firmer, smoother, skin!
Evens out skin tone
Regular exfoliation of dead skin cells eventually lightens dark spots and hyperpigmentation.
How do I use lactic acid?
Before you go about using lactic acid on your face, here are important tips to ensure you get the most out of its wonders:
Use at night.
Lactic acid is best used at night. This is because new skin cells are much more prone to sun damage, and skin restoration is at its optimum when you sleep.
Always use sunscreen the morning after.
Because regularly using exfoliants increases sun sensitivity, never forget to apply sun cream with an SPF of at least 30 in the morning.
Alternate with a hydrating serum.
Celebrity aesthetician Renée Rouleau recommends using lactic acid for three nights in a row and then taking a break for the next three nights by using a hydrating serum to nourish the new skin cells.
Check packaging instructions.
As mentioned, lactic acid comes in different forms. The frequency of use depends on whether the lactic acid you’re using is a cleanser, toner, moisturizer, cream, serum, or gel.
Always check your chosen product’s packaging for specific instructions.
What should not be used with lactic acid?
While lactic acid is the gentlest AHA, it is not advisable to mix it with a retinol at the same time of day especially if you have dry and sensitive skin.
However, you can use both during different times of the day or on different days of the week with a day of neither in between.
Lactic acid should also not be used with any citric AHAs. Citric acids or any vitamin C serums are notorious for being highly unstable when mixed with other acids.
Using any other acid with vitamin C destabilizes your skin’s pH balance, making all products useless.
What Is Salicylic Acid?
Salicylic acid is the most popular beta hydroxy acid. Naturally found in willow bark and wintergreen leaves, it is used in cleansers, toners, spot treatments, and serums.
As a BHA, salicylic acid is perfect for annoying breakouts, blackheads, whiteheads, and unsightly pores.
Unlike surface-focused lactic acid, salicylic acid exfoliates from deep within your pores.
It has antibacterial and anti-inflammatory properties, which is why it’s always touted in the skincare world as the holy grail for oily and acne-prone skin.
Benefits of salicylic acid
What exactly does salicylic acid do after it does its job inside your pores?
Accelerates skin cell renewal
Salicylic acid is technically a chemical exfoliant too, so it dissolves dead skin cells just like AHAs and increases cell turnover in the same way.
Reduces redness and inflammation
Did you know that salicylic acid, which belongs to a family of compounds called salicylates, is responsible for the anti-inflammatory action of aspirin?
That means salicylic acid fights any type of skin inflammation just like aspirin!
Fights acne, whiteheads, and blackheads
Because salicylic acid cleanses your pores of dirt, bacteria, excess oil, and dead skin cells, that ultimately means acne, whiteheads, and blackheads won’t have any chance to thrive.
Prevents greasy shine
One huge issue about having oily skin is the look and feel of grease on your face.
Thanks to salicylic acid though, your skin’s overactive oil glands are better regulated throughout the day. Say goodbye to grease!
Large pores are caused by congestion and overactive oil production.
Since salicylic acid unclogs pores and acts as an astringent, you won’t have to worry about enlarged pores anymore.
How do I use salicylic acid?
Because salicylic acid actively penetrates your pores, it’s best to be mindful of the side effects that come along with it.
Use at night.
Salicylic acid needs ample time to work its magic. Just like lactic acid, it also leaves your skin more vulnerable to sun damage, so it’s better to refrain from applying it when the sun is high up.
Always use sunscreen the morning after.
Since exfoliants dissolve the top layer of your skin, never forget to protect your precious new skin cells with sunscreen when you go out in the morning.
Do not use it every day!
Yes, there is such a thing as too much salicylic acid. Using it daily strips your skin of its natural oils, tricking your body into producing even more oil than usual.
Watch out for irritation if you have dry skin.
If you have dry skin, to begin with, salicylic acid will absorb all the vital oils you have left and result in flaky, red skin! So don’t use it too much too often.
What should not be used with salicylic acid?
Considering that salicylic acid is a much stronger ingredient than lactic acid, it should not be used with a retinol at the same time of day, unless you have really, really oily skin.
Even then, mixing them together should be done with caution (i.e., start this routine gradually).
Likewise, other BHAs should not be used with salicylic acid.
Too much of the same acids on your face is not just redundant; it’s also drying and irritating to the skin and may cause flare-ups, redness, stinging, and sensitivity.
Vitamin C should be also avoided when using salicylic acid for the same reason that vitamin C should not be mixed with lactic acid: it removes all applied acids’ effects, wasting all your products.
Lastly, salicylic acid should not be used with the most potent AHA, glycolic acid, in order to prevent irritation and dryness.
Can I Use Salicylic Acid and Lactic Acid Together?
Since salicylic acid should not be used with glycolic acid (an AHA), is it fine to mix lactic acid and salicylic acid together?
Fortunately, the answer is yes!
Being the mildest AHA, lactic acid is completely safe when used with salicylic acid at the same time of day.
This is because salicylic acid and lactic acid target different layers of the skin, which means using them both won’t overclean your pores or overhydrate your skin.
However, keep in mind that you’re using two types of exfoliants, so make it a point to lather on lots of sunscreens the next day.
When applying salicylic acid with lactic acid, make sure to follow these two general rules:
1. Introduce different skin care products gradually.
This includes doing a skin test to check whether you’re allergic to the product or not.
And when you decide to add a new product to your routine, wait a few days before your next application.
This allows your skin to restabilize its pH levels, thereby ensuring the full effectiveness of other products.
2. Apply the product with the thinnest consistency first; the thickest ones come in last.
This means cleansers and toners come in first, while moisturizers and sunscreens come in last.
Whichever product contains your AHA or BHA, make sure whichever is thinner in consistency is used first.
Lactic Acid Versus Salicylic Acid: Which Is Better?
The verdict is … neither! You can’t pit these two against each other since they suit different skin types, and when carefully used together, both actually make a lovely duo.
Whether you choose lactic acid or salicylic acid or both, just don’t forget to put on sunscreen!