Salicylic acid

What is it? Salicylic acid is a beta hydroxy acid that is primarily used as a chemical exfoliant in skincare. It’s very common in anti-acne products as its oil-soluble-ness means it is able to get into pores and break down clogs and other gunk that can lead to pimples and congestion.

Learn heaps more about salicylic acid with this fantastic post from Simple Skincare Science: Salicylic Acid for Skin Explained (34 Studies): Everything You Need to Know! Some key, interesting points from the post:

  • Salicylic acid is not pH dependent.
  • A 2% solution used for 3.5 weeks did not increase susceptibility to sunburn.
  • Start low and go slow!
INCI Salicylic acid
Appearance Fine white crystalline powder
Usage rate 0.1–2%.

Salicylic acid is a restricted ingredient in Canada with a maximum usage rate of 2% in cosmetic products.

Scent Nothing noticeable
Approximate Melting Point 159°C (318°F)
pH 2.4
Solubility Salicylic acid isn’t terribly soluble:

Source: Making Cosmetics

Why do we use it in formulations? Salicylic acid is anti-inflammatory, prevents & addresses clogged pores, improves skin cell turnover, chemically exfoliates, and has anti-bacterial properties.
Do you need it? No, but if you are interested in anti-acne skincare it’s a good ingredient to have.
Refined or unrefined? Salicylic acid only exists as a refined ingredient. You can purchase less potent white willow bark solutions and extracts; refer to supplier documentation for usage (here’s an example).
Strengths Effective, proven anti-acne active ingredient.
Weaknesses Salicylic acid can be irritating if over-used. Start with low concentrations and infrequent (2–3x/week) use. Increase usage slowly.
Alternatives & Substitutions Allantoin is also anti-inflammatory and keratolytic, so that could be a potential option.

Alpha hydroxy acids like lactic acid and glycolic acid are also chemical exfoliants, though they are water soluble.

How to Work with It Wear a mask, eye protection, and gloves when working with pure salicylic acid as it is both potent and floaty.

Do not exceed 2% usage rate.

You’ll need to include an adequate amount of solvent to dissolve the salicylic acid; how much is enough will depend on what solvent you’re using.

Aim for a final pH of no less than 3.2–3.8 in hydrous formulations. Salicylic acid is not pH dependent (source).

Storage & Shelf Life Stored somewhere cool, dark, and dry, salicylic acid should last at least five years.
Tips, Tricks, and Quirks Do not use salicylic acid if you’re allergic to aspirin.
Recommended starter amount 30g (1.06oz)
Where to Buy it  Buy it from an online DIY ingredient supplier or Amazon.

Some Formulations that Use Salicylic Acid


Posted on

June 22, 2022