|What is it?
|Tetrahexyldecyl Ascorbate is a stable, oil-soluble form of vitamin C, offering the benefits of L-ascorbic acid without the formulation challenge.
|Clear oily liquid
|0.5–20% (I’ve found upper limits ranging from 2 to 20%; the listed range is from Simply Ingredients)
|Approximate Melting Point
|Liquid at room temperature
|Why do we use it in formulations?
|Like L-ascorbic acid, Tetrahexyldecyl Ascorbate can help reduce pigmentation and age spots, increase collagen synthesis, and is a powerful antioxidant.
Unlike L-ascorbic acid, Tetrahexyldecyl Ascorbate is oil soluble (so it can be used seamless in anhydrous formulations) and it’s stable, so you don’t have to worry about pH and oxidization when formulating with it. It’s also less irritating than L-ascorbic acid.
|Do you need it?
|No, but I’d consider it a great luxury ingredient.
|Refined or unrefined?
|Tetrahexyldecyl Ascorbate only exists as a refined ingredient.
|It works and it’s easy to work with!
|It’s really expensive.
|Alternatives & Substitutions
|A different oil-soluble format of vitamin C like L-Ascorbyl Palmitate would be a good place to start.
Depending on the formulation you could look at other forms of vitamin C, like Sodium Ascorbyl Phosphate, Magnesium Ascorbyl Phosphate, or L-ascorbic acid.
Different formats of vitamin C will have different formulation requirements and usage rates, so make sure you are doing your research to ensure compatibility, safety, and success.
Depending on the formulation and role Tetrahexyldecyl Ascorbate is meant to play in it, you could also try replacing it with a different ingredient (or ingredients) that offer similar benefits. For example, Niacinamide (Vitamin B3) also has skin brightening benefits, and Tocopherol (Vitamin E) is a great antioxidant.
|How to Work with It
|A pH of 3–6 is recommended for hydrous formulations. Avoid prolonged heat, Sandream Impact recommends 80°C as the maximum temperature.
|Storage & Shelf Life
|Stored somewhere cool, dark, and dry, Tetrahexyldecyl Ascorbate should last 3 years.
|Tips, Tricks, and Quirks
|According to Sandream Impact, “THDA [Tetrahexyldecyl Ascorbate] is approved as a quasi-drug in Korea at 2%, and in Japan at 3%.”
|Recommended starter amount
|Where to Buy it
|Buy it from an online DIY ingredient supplier; mine was a gift from Simply Ingredients.