Medically reviewed by Kristin Hall, FNP
Written by Our Editorial Team
Last updated 9/5/2021
While anything with the word “acid” in the name may sound like a no-go for use on your skin, both salicylic acid and azelaic acid are popular topical skincare ingredients that can boost your routine when it comes to managing acne on your face.
In fact, willow bark, in which salicylic acid is naturally present, was allegedly prescribed by Hippocrates to reduce fever and help with laboring pains over 2000 years ago.
The two ingredients have some overlap, including their antibacterial and anti-inflammatory properties, and the fact that they both target the epidermis, or outermost layer of the skin.
However, they have fundamental differences, as well.
This article will tell you everything you need to know so that you can make the best choice for your skin.
The first step to understanding salicylic and azelaic acid’s role in combating acne is understanding how acne works.
Acne occurs when hair follicles become blocked by a combination of oil and dead skin cells.
Our hair follicles are connected to what are known as sebaceous glands, which secrete oil known as sebum to lubricate the hair and skin.
Sometimes, those glands release an excess of sebum, creating the perfect environment for our natural oils to combine with dead skin cells and plug our hair follicles.
When these plugs form, the bacteria that naturally live on our skin will sometimes join the party, getting below the surface to cause inflammation, resulting in papules, pustules, nodules or cysts.
Acne can be tough to treat, cause discomfort and pain and also impact confidence — especially in cases of severe acne.
Here’s how salicylic acid and azelaic acid work to treat it.
Salicylic acid is benzoic acid derivative and skin exfoliant that works to dissolve the sebum that binds the plugs in our pores and cause acne, making it easier to clear our pores of debris.
While commonly used to clear and prevent pimples and blemishes in people who have acne, it can also be used to treat conditions that result in scaling or overgrowth of skin cells, such as psoriasis, ichthyoses, dandruff, corns, calluses and warts on the hands or feet, as well as a range of other skin conditions like mela
sma, photodamage, freckles and lentigines.
Salicylic acid is naturally produced in willow bark, sweet birch and wintergreen leaves, but it can also be synthesized artificially.
You’ll find this powerful ingredient in a number of skin products, including spot treatments, cleansers, toners, peels and body washes, with over-the-counter products capping out at 5% concentration.
The power of salicylic acid and its exfoliating properties lie in the fact that it is classified as a beta hydroxy acid.
As you learn more about this drug, you’ll likely come across frequent references to beta hydroxy acids and alpha hydroxy acids.
Without getting too deep into the chemistry, alpha hydroxy acids are water soluble, while beta hydroxy acids are oil soluble.
Therefore, alpha hydroxy acids (like glycolic acid and lactic acid) work just on the surface of the skin, while salicylic acid is able to penetrate a bit further into the epidermis.
Salicylic acid’s ability to break down oil is exactly what enables it to work against those plugs that cause acne. It dissolves the sebum within our hair follicles to make the debris easy to exfoliate away.
It also has the added bonus of decreasing the production of sebum in patients with acne, making it particularly effective for those with oily skin. Effectively, salicylic acid functions as a chemical peel for the skin.
Check out our full guide to using salicylic acid to treat acne.
Azelaic acid is a saturated dicarboxylic acid found naturally in wheat, rye and barley, and is also produced by a species of fungus that is often found on human skin.
The azelaic acid used in skin products however, is lab produced for quality control.
Azelaic acid can be used to treat mild to moderate inflammatory acne, rosacea and melasma.
Azelaic acid can be found as a prescription cream at 20% concentration, a gel or foam in a 15% concentration.
Like salicylic acid, azelaic acid works on the skin’s epidermis. Rather than focusing on dissolving the sebum in your pores however, it instead inhibits the buildup of bacteria that causes acne on the skin, helping to keep pores clear.
Okay, it’s time for a quick refresher.
In a nutshell, salicylic acid works by targeting the sebum that combines with dead skin and bacteria to plug up your pores, while azelaic acid targets the bacteria itself and focuses on stopping it from building up in the first place.
Now that we have the differences, what are the similarities? Well, both acids are:
Keratolytics. Keratolytics are chemical agents that work to dissolve flakes and scales of skin, making both acids effective at combating conditions that result from the buildup of skin (like psoriasis). Additionally, this process may encourage the growth of new skin and lighten scars and dark spots left behind by acne flares.
Antibacterial. While salicylic acid's antibacterial properties are secondary to its ability to dissolve sebum, this property plays an important role in maintaining healthy skin after acne has been managed. For azelaic acid, its antibacterial properties are the main event.
Anti-inflammatory . You know the drill. A pimple appears, you pick at it against your own best interests, bacteria gets involved and you pick at it even more. Well, both acids help reduce the inflammation that sometimes leads to persistent picking.
With great power comes great responsibility, and incorporating either salicylic acid or azelaic acid into your skin routine should be done with care. Here are some things to know:
Wear Sunscreen. Salicylic acid leaves your skin more vulnerable to sun damage, while azelaic acid does not pose this risk. However, if you’re using azelaic acid for hyperpigmentation, sun exposure can undo all of your hard work, so be extra certain to properly protect your skin with sunscreen.
Be Patient. Both acids take a few weeks to do their job, after which you may continue to use the product to maintain the health of your skin. Therefore, be patient with your new routine.
Test a Little.
As with any new skincare product, you never want to dive in without a test run. Try the new product on a small patch of skin, and if that goes well, incorporate your new product with a low frequency at first to allow your skin to adjust to the change.
Irritation Happens. Previous point aside, it isn’t uncommon to experience skin irritation with the use of azelaic and salicylic acids. Both products do a number on your skin (in a good way), but if it gets to be too much reach out to your dermatology provider for guidance.
Since both acids help remove flaky skin and therefore encourage the growth of new skin, they can have a drying effect. Make sure that you use a moisturizer to give your skin the boost it needs to fully heal, especially if you have naturally dry skin.
Both salicylic acid and azelaic acid are effective & safe drugs for getting acne under control and keeping it under control.
Their antibacterial and anti-inflammatory properties provide an extra boost to calm skin.
Your dermatology provider will know best which acne treatment will be best for your skin and any issues you may be facing.
If you can use some guidance and tools in combating your acne, consult a dermatology practitioner to learn about the options available to you.
Just don’t forget to be patient on your journey to healthier skin.