Tetrahexyldecyl Ascorbate
Vitamin C DerivativeBrighteningAntioxidantAlso known as: THDA, Ascorbyl Tetraisopalmitate
Tetrahexyldecyl ascorbate (THDA), also known as ascorbyl tetraisopalmitate, is a lipid-soluble ester derivative of L-ascorbic acid created by linking four 2-hexyldecanoic acid chains to the ascorbic acid molecule. This lipophilic modification fundamentally changes the skin penetration profile of vitamin C, allowing THDA to traverse the lipid-rich stratum corneum far more efficiently than water-soluble forms. Once inside the skin, cellular esterases cleave the ester bonds to release free ascorbic acid directly within the cells. THDA is one of the most stable vitamin C derivatives available, resistant to oxidation by air and light, and effective across a wide pH range including neutral pH. Its oil-soluble nature makes it particularly suitable for anhydrous formulations, facial oils, and emulsion-based products, and it is well tolerated even by sensitive and rosacea-prone skin types.
Routine placement
Serum · AM
Time to results
6-12 weeks for brightening and dark spot fading
Penetrates deeply into the skin through the lipid matrix of the stratum corneum, delivering ascorbic acid directly to viable epidermal and dermal cells. Provides antioxidant protection at the cellular level, neutralizing intracellular reactive oxygen species. Stimulates collagen synthesis from within the dermis by delivering ascorbic acid to fibroblasts more efficiently than water-soluble derivatives. Inhibits melanogenesis through intracellular suppression of tyrosinase, contributing to gradual skin brightening. Offers exceptional stability in formulation, maintaining potency throughout the product shelf life without the discoloration typical of L-ascorbic acid products. Compatible with oil-based formulations, making it ideal for dry or mature skin types seeking vitamin C benefits in a nourishing vehicle.
Apply THDA serums or oils to clean skin in the morning or evening. Because it is oil-soluble, THDA is often formulated in facial oils, oil serums, or anhydrous balms and should be applied after water-based products but before heavier creams or occlusives. In the morning, apply before sunscreen. THDA can be layered with water-soluble actives such as hyaluronic acid and niacinamide without compatibility issues, as it operates in a different phase. Effective concentrations range from 1% to 10%, with some formulations going as high as 20%. Allow the oil to absorb for a few minutes before proceeding with makeup or sunscreen application.
Research published in Biological and Pharmaceutical Bulletin demonstrated that tetrahexyldecyl ascorbate penetrates the skin at significantly higher levels than L-ascorbic acid and magnesium ascorbyl phosphate in ex vivo human skin models, with greater accumulation in both the epidermis and dermis. In vitro studies confirm that THDA is converted to free ascorbic acid by intracellular esterases in human keratinocytes and fibroblasts, with subsequent stimulation of type I collagen mRNA expression. A clinical study found that 10% THDA cream reduced hyperpigmentation scores and improved overall skin luminosity in subjects with melasma after 16 weeks of use, with no adverse events. Stability testing shows that THDA retains over 95% of its potency after 12 months at room temperature in both anhydrous and emulsion formulations, outperforming all water-soluble vitamin C derivatives. Comparative penetration studies using Franz diffusion cells demonstrate approximately 3 to 5 times greater percutaneous absorption for THDA compared to L-ascorbic acid at equivalent concentrations.
Cautions
THDA is very well tolerated and almost never causes the stinging, redness, or dryness associated with L-ascorbic acid. However, its oil-based nature may not be ideal for very oily or acne-prone skin, as the lipid carrier can potentially contribute to congestion in some individuals. The conversion efficiency from THDA to free ascorbic acid in the skin is subject to individual variation depending on esterase enzyme activity. Results may be more gradual compared to direct L-ascorbic acid application despite superior penetration, because the intracellular conversion rate is a limiting factor. High-concentration THDA products can feel greasy if over-applied.
What does Tetrahexyldecyl Ascorbate do for skin?
Tetrahexyldecyl Ascorbate is used in skincare primarily as a vitamin c derivative ingredient. Its effects depend on concentration and formulation. Check the benefits section above for specific details.
Is Tetrahexyldecyl Ascorbate safe for sensitive skin?
Tetrahexyldecyl Ascorbate is generally well-tolerated, but sensitivity varies by individual. Start with a patch test if you have reactive skin, and introduce gradually into your routine.
Can I use Tetrahexyldecyl Ascorbate every day?
For most skin types, daily use is appropriate at standard concentrations. If you experience any irritation, reduce frequency to every other day.
How long does Tetrahexyldecyl Ascorbate take to fade dark spots?
Most brightening ingredients take 8-12 weeks of consistent daily use to show visible improvement in hyperpigmentation. Results vary by skin tone and spot severity.
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