Ascorbic acid (vitamin C)

What is it? Ascorbic acid is also known as vitamin C; it’s a potent antioxidant with fabulous brightening + collagen-boosting skincare benefits.
INCI Ascorbic acid
Appearance Crystalline white powder; much like table salt or sugar.
Usage rate 3–25% (source)
pH 2.2–2.5 (5% solution in water) (source)
Solubility Water soluble
Why do we use it in formulations? Vitamin C helps increase collagen production, reduce excess pigment/brighten the complexion, boost healing, and counter UV damage. It’s an amazing, well-studied skincare active. Learn more about it with this great post from LabMuffin!
Do you need it? No, but if you’re interested in formulating high-performance skincare products it’s definitely something to consider.
Refined or unrefined? Pure ascorbic acid only exists as a refined ingredient.
Strengths Ascorbic acid is a well studied, highly effective skincare active. It’s also pretty inexpensive!
Weaknesses Ascorbic acid is very unstable in water, breaking down in less than a month.

Ascorbic acid can also be irritating to the skin, with higher concentrations having a higher irritation potential. More isn’t necessarily better; start with a lower concentration and work your way up if desired/required.

Alternatives & Substitutions Vitamin C derivatives like Tetrahexyldecyl Ascorbate, Ascorbyl Palmitate, magnesium ascorbyl phosphate, sodium ascorbyl phosphate, and L-ascorbyl palmitate can be good alternatives. These derivatives can be oil or water soluble, so make sure the solubility is compatible with your formulation. These derivatives are typically more stable than ascorbic acid and less irritating, but they’re generally not as effective and they’re usually more expensive ($7/oz vs $20/oz).

You can also look at using other ingredients that also offer similar skincare benefits (you may want to blend two or three ingredients). Niacinamide (Vitamin B3) would be my top choice as it has both skin-brightening and collagen-boosting effects. N-Acetyl Glucosamine (NAG) also offer skin-brightening benefits. Vitamin E is a great antioxidant.

How to Work with It When formulating with ascorbic acid and water you’ll need to include ingredients that stabilize it and/or plan to use it within a week or two. For a formulation including stabilizers, check out this Skinceuticals-Dupe Vitamin C serum from The Acid Queen. For an easier, use-it-up fast formulation, Lab Muffin has shared a 5-minute DIY Vitamin C Serum formulation.

As ascorbic acid is very acidic you’ll need to raise the pH of your formulation to around 3.5 using something basic; a 10% sodium hydroxide solution works well for this job.

You can also use ascorbic acid in anhydrous formulations, like ones sold by The Ordinary and Paula’s Choice. Since ascorbic acid won’t dissolve in an anhydrous base you’ll want to use a finely powdered version for a smooth finished product; you can purchase extra-fine versions or use a coffee grinder/mortar & pestle.

Storage & Shelf Life Lotion Crafter recommends purchasing ascorbic acid in amounts you can use up in 3–4 months. Learn more here.
Tips, Tricks, and Quirks Don’t use ascorbic acid products with copper ions or benzoyl peroxide as those ingredients will deactivate the vitamin C (source: LabMuffin).
Recommended starter amount 30g (1.06oz)
Where to Buy it Buy it from an online DIY ingredient supplier or Amazon. This is an ingredient that you can purchase as a supplement, just be sure to choose a pure powdered version rather than pressed tablets (those will have some other ingredients in them to bind the tablet together). The powdered L-ascorbic acid that The Ordinary sells will also work, and is reasonably priced for a small amount.

Some Formulations that Use Ascorbic Acid


Posted on

August 17, 2022