Get ready people. This is going to be a pretty long post but it’s the ultimate guide to exfoliating acids (aka chemical exfoliants). There are three types of acids: alpha-hydroxy acids (AHAs), beta-hydroxy acids (BHAs) and poly-hydroxy acids (PHAs). While no acid is better than the other, they do target different skin types and needs. We’re going to cover what the different acids are, what they do for the skin, how to decide which acid to use and how to incorporate it into your routine. So buckle up!
What are Exfoliating Acids?
First things first: what is an exfoliating acid? By now, you might be familiar with physical exfoliants such as facial scrubs and tools that physically exfoliate the skin. However, it’s important to be gentle with these products as they can be quite harsh and cause micro-tears in the top layers of the skin. This is why it’s best to keep physical exfoliation to a minimum and to switch to acids. Exfoliating acids contain ingredients that help remove dead skin cells without having to physically scrub the skin. They unstick the ‘glue’ that holds dead skin cells together, encouraging cell regeneration to reveal fresh, glowing skin.
Alpha-Hydroxy Acids (AHAs)
What are AHAs?
Alpha-hydroxy acids are derived from plant sources such as sugar cane and fruit. There are a number of acids that fall under the AHA category, namely glycolic acid, lactic acid, and malic acid. While each acid has its own set of benefits, they all perform the same basic function of exfoliating the skin’s surface layers.
- Exfoliates the surface layer of the skin: AHAs exfoliate the skin by splitting the bonds between dead skin cells at the surface of the skin. Once cut loose, the cells fall off, encouraging the skin to generate new cells. This leaves the skin looking brighter and more radiant.
- Evens texture: By removing dead skin cells, the newer and healthier cells underneath are no longer hidden, leaving a smoother and more even texture.
- Increases collagen production: Certain AHAs are able to penetrate the skin on a deeper level to promote collagen production. This is great for anti-ageing purposes as collagen reduces the appearance of fine lines and wrinkles.
- Hydration: Most AHAs are humectants which means that they attract water to the skin, helping it to stay hydrated.
Beta-Hydroxy Acids (BHAs)
What are BHAs?
Beta-hydroxy acids are a group of organic acid compounds that are best known for their acne-busting superpowers. They are oil-soluble, meaning that they are able to penetrate into the pores and clean out oil to prevent breakouts. BHAs are often preferred by oily skin types that are prone to bumps, clogs, blemishes and enlarged pores.
- Exfoliates the top layers of the skin: BHAs soften, separate and shed the top layer of dead skin cells. By sloughing off the dead skin, it encourages cellular turnover to improve skin dullness and texture.
- Removes excess oil: Since BHAs are oil-soluble, they work beneath the skin’s surface to clean out excess oil from your pores. This can then lead to an improvement in the appearance of pores.
- Cleanses clogged pores: BHAs are able to penetrate the pores and loosen the glue that holds skin cells and debris together, removing the contents of the clogged pore.
- Prevents superficial breakouts: Not only do BHAs directly treat existing breakouts, but they also prevent them from returning.
- Reduces inflammation: Due to the anti-inflammatory properties of BHAs, it helps with any irritation and redness caused by breakouts.
Poly-Hydroxy Acids (PHAs)
What are PHAs?
Poly-hydroxy acids (PHAs) are very similar to traditional AHAs because both exfoliate the skin by dissolving the glue that binds dead cells to the surface of the skin. The main difference between them is their molecular structure – PHAs have much larger molecules. This means that they cannot penetrate the skin as deeply as other acids, working exclusively on the skin’s surface without disturbing the deeper layers.
- Non-irritating exfoliant: PHAs are a great alternative to AHAs as they offer the same exfoliating benefits but are less likely to cause irritation.
- Gentle on the skin: PHAs are much gentler on the skin due to their large molecule size.
- Hydration: Just like AHAs, PHAs are humectants that attract and retain moisture in the skin to keep it hydrated.
- Anti-inflammatory and antioxidant properties: PHAs also contain tons of anti-inflammatory and antioxidant properties that are great for fighting bacteria, redness, and for protecting the skin from environmental stressors.
AHAs vs BHAs vs PHAs
Now that we’ve covered each acid group, what are the main differences between them all?
Here’s a quick summary:
Choosing the Right Acid
To break it down:
- AHAs may be more appropriate for age-related and/or dry skin concerns
- BHAs might be best for oily, acne-prone skin
- PHAs are good for more sensitive skin that cannot tolerate the other acids
When choosing an acid, it comes down to the way you want the products to work. If your goal is to exfoliate only the top layer of your skin, you should be using an AHA or PHA. If your skin concerns are deeper, such as acne, you’ll want to use either BHA or an AHA/BHA combination.
It’s also important to note that products containing AHAs can cause a slight tingling sensation which is totally normal! But if the tingling feeling leads to redness, wash off immediately and use hydrating products to soothe the skin.
Mixing Exfoliating Acids
It’s also important to be careful when mixing your acids as it can cause irritation if doses are too high. However, mixing AHA, BHA and PHA products can work wonders for the skin if you are choosing well-balanced and gentle exfoliants. The key here is to monitor how your skin reacts and adjust your usage accordingly. If you’re too nervous to mix your acids, try alternating them throughout the week or find products that contain a balanced blend of the different acids.
Mixing with Active Ingredients
Remember to be mindful of other active ingredients (such as retinol and antioxidants) when using acids. Too many active ingredients can cause an imbalance in the skin which can lead to irritation and breakouts. As a rule of thumb, avoid using vitamin C and retinol with your acids in the same routine.
It’s also worth noting that acids do make your skin more sensitive to sunlight, so be extra diligent about applying and re-applying SPF afterwards or use acids in your PM routine instead. Don’t make the mistake of using an acid-based product in the morning without following with SPF after – your skin is much more likely to burn and breed irritations.
When to Use Exfoliating Acids
Once you’ve found the right product for you, make sure that you do not overuse it. Over-exfoliation is a common mistake that many people make when using acids.
Using Acids in Your Early 20s
If you’re under 20 years old, you should not be using any exfoliating acids unless prescribed by a professional. In your early 20s, though, you can start introducing exfoliating acids into your routine by using lower concentrations a few times a week. Start with a glycolic acid 5% (for normal/combination/dry skin) or salicylic acid 0.5% (for acne-prone/oily/combination skin) around three times a week. Higher concentrations can be used for a deeper exfoliation, but should not be used more than once weekly. It’s important to remember to avoid using on broken or inflamed skin!
Using Acids from Ages 25-35
At this point, most skin types can tolerate a glycolic acid 10%, but those with sensitive skin should always patch test first. For dry and dehydrated skin, lactic acid is gentler and is slightly more hydrating. This can be used up to four times a week.
Salicylic acid 2% is great for oily skin types and acne sufferers as this mild ingredient regulates oil production and unclogs the pores. A cleanser with salicylic acid is safe for daily use at this stage, but a higher concentration or a leave-on product should be used every other day or once daily at most. It’s always best to read product instructions when deciding how to incorporate acids into your routine!
Using Acids from Ages 35-45
While the visible ageing process might start setting in, you don’t need to dramatically ramp up your acid usage. Simply hone your daily routine and continue with your acid usage above to make sure you’re taking care of your skin.
Using Acids from Age 45+
If you have been using exfoliating acids over time, your skin should have built up a pretty good tolerance to them. If you’re happy using glycolic acid, try a 10% formula for daily use, or a 30% once or twice a week. For lactic acid, try a 10% formula every other day. For oily skin, a salicylic acid cleanser can be used twice a day, followed with the use of a 10% glycolic acid toner every other day.
Following each acid-based product, it’s imperative to use SPF daily, even in the winter months!
While this exfoliating solution is super effective, it’s important to note that it might not be suitable for everyone. It can be quite intense, so if you’re looking for a deeper exfoliation, this is a great product for you! Sensitive skin should patch test first, and younger skin should not use this more than 1x a week.
This acid toner is formulated with glycolic acid and betaine salicylate to smooth and balance the skin. This toner is an ideal way to mildly exfoliate on a more regular basis (once a day or every other day) while resetting your skin’s pH and preparing it for the next products in your routine.
This gentle, lightweight serum is a great introduction to exfoliation. It makes use of PHAs, making it more gentle on the skin and safe for sensitive skin types. The serum also contains honey extract, offering soothing and healing properties.
This lightweight serum contains a super-six acid blend (lactic acid, salicylic acid, glycolic acid, mandelic acid, tartaric acid, and pyruvic acid) to clarify pores and support natural cell renewal. It also has activated charcoal and hyaluronic acid to detoxify and hydrate the skin.
If you’re willing to drop some cash on a more premium acid serum, this Drunk Elephant night serum is amazing. Blended with raspberry extract, this 12% AHA/BHA blend helps to refine and resurface the skin, revealing a smoother and more radiant complexion.