If you’ve been wanting to formulate with salicylic acid but haven’t been sure where to start; start here 😄 This five-ingredient Beginner-Friendly Salicylic Acid + Squalane Serum doesn’t contain any water, so you don’t have to worry about pH, making it super simple to whip up. This serum has made my skin more radiant, smooth, and even—I love it, and I think you will, too!

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Salicylic acid is an ingredient I’ve wanted to formulate with for ages. I think it’s probably one of the very first cosmetic ingredients I had any awareness of, dating back to my teenage days, perusing teen magazines for tips on preventing acne (oh goodness, the “toothpaste on zits” advice 😬). A combination of not owning any salicylic acid and being a bit daunted by its limited solubility and pH-plummeting abilities led to me just… formulate other things… for a very long time. Earlier this year Essential Wholesale offered to send me some ingredients, and I decided to take the plunge. I’m so glad I did! Once I started working with it I wondered what I’d been worried about (which is always a nice feeling!).

I got the idea to create an anhydrous salicylic acid formulation from The Ordinary. They make a 2% anhydrous salicylic acid formulation that looked really interesting, and had the obvious benefit of removing pH from the list of things to manage with a formulation. That idea merged with a small salicylic acid fact that has been hanging out in the back of my mind—salicylic acid is salicylic acid is 15–20% soluble in octyldodecanol, which is really quite good solubility for salicylic acid (compare that to its 3–6% solubility in propylene glycol, which is a very common solvent for salicylic acid). Octyldodecanol is a liquid fatty alcohol; much like cetyl alcohol, it’s a non-volatile emollient.

I’ve included salicylic acid at 1% in this formulation, which is more or less in the middle of the recommended usage range for cosmetic products. Salicylic acid is a restricted cosmetic ingredient in Canada, with a maximum usage level of 2% (higher concentrations can be found in drugs, like wart removal products). If you’re new to salicylic acid I’d recommend sticking with that 1% level as a starting point, but if you’re an experienced user and lover of salicylic acid you might want to increase the concentration to 1.5% or 2%. You’ll need to increase the solvent—octyldodecanol—as well. I’ve used a 1:10 ratio of salicylic acid to solvent in this formulation, which is more than strictly necessary, but makes it very easy to figure out how much to increase the solvent if you increase the salicylic acid! 1.5% salicylic acid, 15% octyldodecanol. 2% salicylic acid, 20% octyldodecanol. Simply reduce the squalane to make room for the additional salicylic acid and octyldodecanol, keeping the formulation adding up to 100%.

After the salicylic acid and octyldodecanol, the rest of the formulation is mostly olive squalane with some vitamin E and bisabolol for skin-soothing, anti-inflammatory benefits. If you wanted to swap out some of the squalane for another carrier oil (or blend!), I think that could be lovely—I just recommend sticking to fast-absorbing ones to keep this formulation from feeling greasy.

Making is very easy: dissolve the salicylic acid in the octyldodecanol (a bit of heat is helpful), stir in everything else, and you’re done! Easy peasy 😄

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Relevant links & further reading

• Salicylic acid in the Humblebee & Me Encyclopedia
• Octyldodecanol in the Humblebee & Me Encyclopedia
• Olive Squalane in the Humblebee & Me Encyclopedia
• Tocopherol (Vitamin E) in the Humblebee & Me Encyclopedia
• Bisabolol in the Humblebee & Me Encyclopedia
• Salicylic Acid for Skin Explained (34 Studies): Everything You Need to Know! from Simple Skincare Science
• More discussion & information on formulating with salicylic acid:
  • Salicylic acid in waterless formula; is it effective? on Chemist’s Corner
  • Salicylic acid Spec Sheet from Making Cosmetics
  • Salicylic Acid: Origins, Formulation Strategies & Delivery Forms from UL PROSPECTOR
  • Ingredient Profile: Salicylic Acid from Cosmetics & Toiletries
• More facial serum & cream formulations:
  • Brighten & Boost Facial Serum
  • Brightening Hyaluronic Acid & Niacinamide Facial Serum
  • Hyaluronic Acid B5 Facial Serum
  • Soothe and Glow Facial Gel Cream
  • Ice Palace Ceramide Glow Gel Cream
  • Prickly Pear Eye Gel Cream
  • Goji & Açaí Superfood Face Cream

Beginner-Friendly Salicylic Acid + Squalane Serum

0.2g | 1% salicylic acid (USA / Canada / UK / AU)
2g | 10% octyldodecanol (USA / UK / Germany)

17.4g | 87% olive squalane (USA / Canada)
0.2g | 1% tocopherol (vitamin E) acetate (USA)
0.2g | 1% bisabolol (USA / Canada)

Put on your dust mask and gloves.

Weigh the salicylic acid and octyldodecanol into a small beaker or heat-resistant glass measuring cup. Gently warm to get the salicylic acid to dissolve; I used my hot plate on its lowest setting, but you could also use a water bath. I did try leaving this solution overnight the salicylic acid didn’t dissolve much at all in 8+ hours.

Once the salicylic acid has dissolved, you’ll have a perfectly clear liquid. Weigh in the olive squalane, vitamin E, and bisabolol. Stir to combine—and that’s it!

I packaged my serum in 10mL airless pump bottles from YellowBee (gifted). A 20g batch will be approximately 23mL. If you want to fill a 1 fl oz container, scale the batch up to 25g. I suggest using a bottle with a dropper top or treatment pump cap.

To use, apply a few drops of the serum towards the end of your skincare routine, after cleansing and more watery products.

Start with just 2–3x a week and work up to daily use, making sure you’re paying attention to your skin and how it is reacting. If your skin is doing well you can work up to using it twice daily, but don’t feel like you have to! If you’re getting the results you need, that’s great. You can also increase the concentration of the serum up to 2%; just be sure to go slowly and make sure you are listening to your skin!

Shelf Life & Storage

Because this product does not contain any water, it does not require a broad-spectrum preservative (broad spectrum preservatives ward off microbial growth, and microbes require water to live—no water, no microbes!). Kept reasonably cool and dry, it should last at least a year before any of the oils go rancid. If you notice it starts to smell like old nuts or crayons, that’s a sign that the oils have begun to oxidize; chuck it out and make a fresh batch if that happens.

Substitutions

As always, be aware that making substitutions will change the final product. While these swaps won’t break the formulation, you will get a different final product than I did.

• As I’ve provided this formulation in percentages as well as grams you can easily calculate it to any size using a simple spreadsheet as I’ve explained in this post. As written in grams this formulation will make 20g, which is approximately 23mL.
• To learn more about the ingredients used in this formulation, including why they’re included and what you can substitute them with, please visit the Humblebee & Me Encyclopedia. It doesn’t have everything in it yet, but there’s lots of good information there! If I have not given a specific substitution suggestion in this list please look up the ingredient in the encyclopedia before asking.
• Do not substitute the salicylic acid or octyldodecanol.
• You can substitute some of the olive squalane for a carrier oil or two your skin loves. I’d keep things light and fast-absorbing, though.
• You can use tocopherol MT-50 instead of tocopherol acetate.
• You can replace the bisabolol with an oil-soluble extract (chamomile or calendula would be lovely), or just use more vitamin E or squalane.
• I don’t recommend adding a fragrance oil or essential oil to this formulation. There’s really no need—save it for your face cream!