Tetrahexyldecyl Ascorbate: The Best Vitamin C for Skin

August 08, 2022

spots of vitamin c oil- thd for skin

THD gives you all the benefits of vitamin C without any drawbacks of L-Ascorbic acid. THD brightens and evens skin tone, fights free radical damage, and supports our skin’s collagen production, while being extremely stable, non-irritating, and is fat-soluble (more on that later). 


What is Tetrahexyldecy Ascorbate?

Tetrahexyldecy Ascorbate, or THD for short, is a stable, oil-soluble form of vitamin C. It helps support skin’s collagen production and promotes a more even skin tone. As it is a powerful antioxidant, it fights free radicals that damage skin.

Until recently the most common form of vitamin C used in skincare was L-Ascorbic Acid. However, L-Ascorbic Acid has several downsides. It is known for being unstable and prone to oxidation. It requires a water-based formula, making it difficult for the serum to successfully penetrate beyond the skin’s protective water barrier. As well, these water-based formulas need to be highly acidic to be effective. This can disrupt a healthy skin barrier and cause skin irritation. Not exactly what you were hoping for, right? 


Benefits of Tetrahexyldecyl Ascorbate For Skin

THD provides the benefits of vitamin C without the drawbacks from traditional formulas.

It is an extremely stable, non-drying, less irritating oil-based form of vitamin C — making it a natural fit with Kari Gran Skincare (we love our oil). As THD ascorbate is a fat-soluble ingredient it actually gets absorbed deeper into skin to deliver its benefits.

As THD is so stable, it doesn’t oxidize or “go bad” as soon as you open the bottle — as L-Ascorbic acid formulas are prone to do. 


The Bountiful Benefits of THD Vitamin C

With the introduction of Tetrahexyldecyl Ascorbate we can enjoy all the wonderful benefits vitamin C is known for within an oil-based serum. 

Tetrahexyldecyl ascorbate promotes the appearance of a brighter, more even skin tone, and can reduce hyperpigmentation. 

THD acts as a powerful antioxidant, protecting the skin from free radicals generated by UV exposure and pollution. 

THD is especially gentle for those with sensitive skin because of its neutral PH and is less irritating than traditional forms of vitamin C found in water-soluble formulas.

THD helps to firm skin and reduce the appearance of wrinkles and fine lines by acting as a precursor for collagen production.  Meaning it helps to simulate and support the body’s natural collagen synthesis (which decreases as we age).

We believe THD is the best vitamin C for dry skin. As it is oil-soluble, it can be combined with moisture replenishing oils that help to soften dry skin, and enhance the brightening, glow-inducing benefits of a vitamin C serum.

The wait is over! Now you can have your vitamin C and Kari Gran, too. We’re so excited to include our new Kari Gran Vitamin C Serum featuring THD into our skincare line.



Clinics in Dermatology, July-August 2008, pages 367-374

Cosmeceuticals Aesthetic Dermatology, Volume 5, 2021, pages 38-46

Dermatologic Surgery, March 2002, pages 231-236


Leave a comment

Comments will be approved before showing up.