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

L-Arginine

What is it? L-Arginine is an amino acid with a basic pH—it’s useful for boosting the pH of our formulations.

It has moisturizing, skin conditioning, and barrier boosting properties, but if used at pH-adjusting amounts those benefits are unlikely to be noticeable in a finished product. The formulations I’ve found that use it as an active ingredient use it at 0.5–2%. Your mileage may vary, though! Depending on the formulation you may be able to work in enough L-Arginine to get skin benefits and a perfect pH.

INCI Arginine
Appearance White crystaline powder
Usage rate As needed to get the pH of your formulation where you want it; generally less than 1%.
Scent Nothing noticeable at pH-adjusting levels.
pH A 10% L-Arginine solution has a pH between 10.5–12.
Solubility L-Arginine is water-soluble.
Why do we use it in formulations? L-Arginine is used to raise the pH of our formulations; I find I’m most likely to need it when working with acid-based natural preservatives that dramatically lower the pH of a formulation.
Do you need it? No, but you should have something to raise the pH of your formulations and this L-Arginine is a good choice if you can get it.
Refined or unrefined? L-Arginine only exists as a refined ingredient.
Strengths An easy, gentle ingredient for raising the pH of our formulations.
Weaknesses It’s not terribly easy to find.
Alternatives & Substitutions A 10% NaOH (lye) solution or triethanolamine will work, but not in the same amounts—if you’re following a formulation that includes L-Arginine to adjust the pH you’ll have to test and adjust with the new base/pH raising ingredient.
How to Work with It L-Arginine isn’t super strong, so you can add the straight powder to some formulations, or make a dilution—whatever works for each formulation. I keep a 10% solution and the pure powder on hand.
Storage & Shelf Life Stored somewhere cool, dark, and dry,
Tips, Tricks, and Quirks Cosmetic grade L-Arginine is not the same as food, dietary supplement, or pharmaceutical grade. I’m unsure if L-Arginine purchased from the drug store would be a good workaround if you can’t purchase cosmetic grade L-Arginine.
Recommended starter amount 30g (1.06oz)
Where to Buy it I’ve only found cosmetic grade L-Arginine at Skin Chakra (Germany) and Essential Wholesale (USA).

Some Formulations that Use L-Arginine

Tocopherol (Vitamin E)

What is it? Vitamin E is a potent antioxidant and beneficial skincare ingredient, helping protect the skin from environmental damage. It’s a naturally occurring vitamin that can be found in many carrier oils, like argan oil and cherry kernel oil, but when we talk about adding vitamin E to our formulations, it is a refined and concentrated ingredient.

The term “vitamin E” refers to 8 different chemical compounds: four tocopherols and four tocotrienols (alpha, beta, gamma, and delta). Different vitamin E products can contain different blends or isolations of these different vitamin E chemicals. Those different blends can mean the product is better suited to certain uses than others, and can also impact the price. I recommend this very thorough article from Skin Chakra to learn more. The Wikipedia article on tocopherol is also very helpful.

It is important to know that vitamin E is not a preservative. While it can help extend the shelf life of our products by delaying the onset of rancidity, it does nothing to prevent microbial growth.

I use Vitamin E MT-50 Full Spectrum in my formulations. This product is composed of 50% tocopherols (d-alpha, d-beta, d-gamma, and d-delta) in a base of GMO-free soybean oil. You could use Vitamin E USP instead, but it is typically more expensive. I don’t recommend using vitamin E capsules or oils that are designed for direct application to the skin as these are not cosmetic ingredients, but cosmetic products.

INCI Tocopherol
Appearance Viscous amber liquid
Usage rate I typically use vitamin E at 0.5% of the oil phase to delay oxidization. New Directions Aromatics recommends 2–30% for skincare benefits.
Texture Sticky, thick
Scent Oily
Approximate Melting Point The 50% vitamin E I have is a thick liquid at room temperature; the more concentrated the product is, the thicker it will be.
Solubility Vitamin E is oil soluble.
Why do we use it in formulations? When you see vitamin E used at low concentrations (≤0.5%), it is there as an antioxidant, acting to delay the onset of rancidity. At concentrations of 2% and more, it will be contributing skin benefits as well as antioxidant benefits to the formula.
Do you need it? Yes.
Refined or unrefined? Vitamin E only exists as a refined product.
Strengths Vitamin E is an excellent, readily available antioxidant that also has skincare benefits.
Weaknesses It can be a bit pricy, but a little goes a long way!
Alternatives & Substitutions Look for other oil-soluble antioxidants; rosemary seed extract is a common one, though it is more expensive.

Vitamin E acetate is not a great alternative for tocopherol if you are including vitamin E in a formulation as an antioxidant (source). Vitamin E acetate can sub in for skin benefits, but not as an antioxidant.

How to Work with It Include tocopherol in the cool-down phase of your formulations.
Storage & Shelf Life Stored somewhere cool, dark, and dry, vitamin E should last 12 months. I don’t recommend purchasing vitamin E in bulk; at 0.5% you likely won’t use much over the course of 12 months!
Tips, Tricks, and Quirks Learn more about vitamin E with this great blog post from Realize Beauty! This awesome post includes a de-bunking of the myth that excess vitamin E becomes a “pro-oxidant”.
Recommended starter amount 30g (1.06oz)
Where to Buy it Buy it from an online DIY ingredient supplier or Amazon. I don’t recommend using dietary capsules, though if you really want to please research exactly what is in the capsules you want to use so you understand what you’ve got.

Some Formulations that Use Vitamin E

Ceramide Complex

What is it? Ceramide Complex is a cosmetic ingredient made from a blend of several different ceramides, free fatty acids, and phytosphingosine.
INCI Ceramide NP, ceramide AP, ceramide EOP, phytosphingosine, cholesterol, sodium lauroyl lactylate, carbomer, xanthan gum.
Appearance White semi-viscous liquid
Usage rate 1–15%
Texture Smooth, semi-viscous liquid
Scent Nothing much
Approximate Melting Point Liquid at room temperature
pH 5.5–7.0
Solubility Water
Why do we use it in formulations? Ceramides are naturally occurring fats that comprise over half of the skin’s barrier, helping protect the skin and retain moisture. They are regularly described as the “mortar” to your skin cell “bricks”. Your body does make ceramides, but they can be depleted by everything from age to hot water to UV exposure. Supplementing your body’s natural supply (and encouraging it to produce more ceramides) through topical application of products containing ingredients like Ceramide Complex can help rejuvenate and strengthen the skin.

Ceramide Complex contains a blend of different types of ceramides as well as the ceramide precursor phytosphingosine, which encourages our skin to make more of its own ceramides.

Do you need it? No, but if you suffer from dry/irritated skin it is a downright wonderful active.
Refined or unrefined? Ceramide Complex only exists as a refined product
Strengths Fantastic skin-identical skin care active.
Weaknesses It’s one of the more expensive ingredients we formulate with.
Alternatives & Substitutions There are quite a few different ceramide products on the market with different INCI values; I’d start there, seeing what is available where you live. I’ve also seen “vegetable ceramides” for sale, which could work—the INCI is very different, but the description of the benefits is very similar.

If you can’t get anything vaguely ceramide-esque you could look at other actives that will help strengthen the skin barrier; N-Acetyl Glucosamine, niacinamide (Vitamin B3), and panthenol (Vitamin B5) would be where I’d start, but make sure those ingredients are compatible with the overall formulation and ensure you are meeting any pH requirements.

You could also just replace the ceramides with more distilled water, but that’s a lot like using water where cream is called for in a soup—you’ll lose all the wonderful ceramide-y benefits, but whatever you’re making shouldn’t break.

How to Work with It Include ceramide complex in the cool down phase of your concoctions. It can result in a loss of viscosity.
Storage & Shelf Life Stored somewhere cool, dark, and dry, ceramide complex should last about 6 months. I store mine in my DIYing fridge.
Tips, Tricks, and Quirks Once you recognize the INCI values for different ceramides you’ll start to recognize them in the ingredient lists for tons of quite expensive skin care products!
Recommended starter amount 30mL (1fl oz) or less, given the short shelf life and high cost. If you can purchase less that might be a good idea, especially if you don’t already have plans to use a full 30mL (1fl oz) quickly.
Where to Buy it  Buy it from an online DIY ingredient supplier (both Making Cosmetics & Windy Point carry it).

Some Formulations that Use Ceramide Complex

Colloidal Oatmeal

What is Colloidal Oatmeal? Colloidal Oatmeal is an ultra-fine, very refined oat flour made from whole oats (including the beneficial bran). It’s a moisturizing skin protectant, recommended for soothing irritated skin. It is not the same thing as hydrolyzed oat protein, and it’s not the same thing as oats you’d grind up at home. Definitely give this article a read to learn more as there are some funny oddities and intricacies.
INCI Avena Sativa Kernel Flour
Appearance Fine off-white powder; looks a lot like all-purpose wheat flour.
Usage rate I’ve found wildly varying ranges. New Directions Aromatics recommends 0.05–2% while Making Cosmetics recommends 5–30%. I tend to use it in the 1–5% range for emulsions, and higher for anhydrous products like bath soaks and cleansing powders.
Texture Fine, smooth powder
Scent Low; slightly oaty, but barely noticeable.
Solubility I’ve found it listed as water-soluble and minimally soluble. In my experience, colloidal oatmeal does not dissolve in water but is so fine that it disperses smoothly in emulsions.
Why do we use it in formulations? Colloidal oatmeal is a great anti-inflammatory/soothing moisturizer, making it great for dry, irritated skin.
Do you need it? No, but I love colloidal oatmeal as a versatile, gentle skincare active.
Refined or unrefined? Colloidal oatmeal only exists as a refined product.
Strengths Excellent skin-soothing moisturizer, all-natural, inexpensive.
Weaknesses If you have a topical sensitivity to gluten there is a chance of cross-contamination.
Alternatives & Substitutions Panthenol is both soothing and moisturizing, so it could be a good alternative. You could also look at combining something soothing (like calendula extract) with something moisturizing (glycerin, propanediol, hydrolyzed proteins, etc.). Urea is also worth considering.
How to Work with It Colloidal oatmeal can be hot or cold processed, depending on the needs of the formulation. In emulsions I like to include it in the heated oil phase so it doesn’t cook up into a gloppy porridge if heated with the water phase. You can include it in the heated water phase if you want to, but I find it is much neater/easier to include it in the heated oil phase.
Storage & Shelf Life Stored somewhere cool, dark, and dry, colloidal oatmeal can last up to two years.
Tips, Tricks, and Quirks Check out this interesting article on the intricacies and oddities of colloidal oatmeal from LisaLise.
Recommended starter amount 30g (1.06oz)
Where to Buy it  Buy it from an online DIY ingredient supplier or Amazon.

Some Formulations that Use Colloidal Oatmeal