Hyaluronic acid is a skin hydrator, not an exfoliant like salicylic acid. You can definitely use both. In fact, applying hyaluronic acid with your salicylic acid is a very good idea. Salicylic acid can be a little drying to the skin because it's job is to absord excess oil.
Salicylic acid is ideally applied to dry skin while hyaluronic acid is ideally applied to damp skin and followed with a heavier moisturizer/occlusive to lock in moisture. Damp skin is more permeable which means that skincare ingredients find it easier to penetrate your skin's barrier.
Absolutely, hyaluronic acid and salicylic acid are perfectly safe to use together. This is because, although they are both carry the name acid, they do in fact work very differently on the skin. Hyaluronic acid is a highly effective skin ingredient because of the humectant properties it contains.
But overall, stick to using water-based products and serums together. AHAs and BHAs, such as glycolic, salicylic, and lactic acids should never be used with Vitamin C. Vitamin C is an acid, too, and is unstable, so the pH balance will be thrown off by layering these ingredients together and might as well be useless.
The key difference between salicylic acid and hyaluronic acid is that salicylic acid is a monomeric substance, whereas hyaluronic acid is a polymeric substance. Moreover, application-wise, salicylic acid is used as a medication in treating warts, dandruff, acne and other skin disorders.
“You can use a salicylic acid–based cleanser in the morning to unclog pores and avoid acne and a glycolic acid–based cleanser at night to exfoliate your skin and get rid of dead skin cells,” notes Jailman.
By using a salicylic acid enriched wash after cleansing the skin of any remaining makeup, you are helping to rid the skin of any dead skin cell build-up allowing any nourishing products applied afterwards to absorb quicker into the lower layers of the skin and show results quicker.
"If salicylic acid is an ingredient in your cleanser, it is fine to use it every day." However, if you are using an exfoliant that salicylic acid in the formula, Dr. Hu advises only using the product three times per week, to avoid over-exfoliating the skin and drying it out.
Don't use with: Although salicylic acid can be combined with other exfoliating ingredients, Mudgil says that in order to avoid irritation, it's best to stick to only one exfoliant at a time.
Niacinamide & Salicylic Acid
Niacinamide, a water-soluble form of vitamin B3, and salicylic acid, a beta-hydroxy acid, work particularly well when combined together. Both have anti-aging and anti-acne effects and offer some level of UV protection.
Can niacinamide and salicylic acid be used together? The simple answer is yes. They complement each other well. Being oil soluble, salicylic acid can penetrate deeper into the skin layers, but it can also dehydrate and irritate skin.
You'll want to use your BHA product first, not only because BHAs are lower in pH but also because they are oil soluble and AHAs are not.
Can I apply moisturizer after using salicylic acid? Yes. Moisturizers can help hydrate and repair skin, making it a good step to do after using an exfoliating treatment with salicylic acid.
It works by penetrating and dislodging the gunk (sebum) in your pores, so that it's no longer trapped — resulting in a lower chance of triggering an acne breakout." When you combine salicylic with a moisturizer, you're essentially chemically exfoliating your skin while also giving it the hydration it needs to avoid—you ...
A thick moisturizer with hyaluronic acid would be applied after a vitamin C serum, but a hyaluronic acid serum will come before a face cream with vitamin C in its formula. In the case that you have two separate serums, it still comes down to thickness. Apply whichever is thinner first.
Products that may cause purging
Retinoids such as Tretinoin, acids such as salicylic, and benzoyl peroxide are just a few of the products that cause purging. These products contain active ingredients that increase the skin cell turnover rate, therefore causing your skin to purge.
Apply hyaluronic serums after cleansing (and toning, if you use a toner). Moisturizers go over the top. During the day, your SPF will be your last skincare step. Most people notice a difference in how their skin feels immediately after applying a hyaluronic acid product.
Can I moisturise after salicylic acid? Absolutely, if anything I strongly suggest moisturising after using salicylic acid. Not only will this soothe and calm the skin after applying the potent BHA to your skin.
You can test this yourself with a well formulated exfoliant: at night, apply your AHA or BHA as usual after cleansing and toning, and do a "split-test." Wait 20 minutes before applying your serum and/or moisturizer to one side, but the other side of your face, apply those next steps immediately.
It will appear that applying hyaluronic acid after salicylic acid is a natural step that occurs when applying your skincare routine.
Second, avoid anything with harsh ingredients like alcohol and fragrance, or anything with a high acid concentration. “The majority of over-the-counter (OTC) cosmetic creams, lotions, and serums are water based and contain less than 2 percent hyaluronic acid,” Frey explains.
It is considered the best idea to apply niacinamide before salicylic acid. This is because the humectant traits of niacinamide ensure the natural skin barrier contains the correct levels of water. When the skin barrier is moisturised and healthy it can keep itself protected from exposure to free radical damage.
Niacinamide tends to work best in an environment with a neutral pH and because salicylic acid is, well, an acid it does not have a netural pH – it has an acidic one. If you want to use them both one after the other, the best thing to do is apply your salicylic acid, wait 10-30 minutes then apply your niacinamide.
Using both together will however can become too much for the skin and lead to irritation, rashes, redness, flakiness and all-round discomfort. Much like vitamin C and niacinamide, if you are wanting to use both separate the products completely and apply salicylic acid in the morning and retinol for the evening.