Ingredient · Vitamin C Derivative (Fat-Soluble)
Tetrahexyldecyl Ascorbate (Fat-Soluble Vitamin C Derivative)
INCI · Tetrahexyldecyl Ascorbate
Related names and forms: THD Ascorbate. This list does not indicate synonyms or exact ingredient matches.
Tetrahexyldecyl ascorbate (INCI: Tetrahexyldecyl Ascorbate; THD ascorbate) is a stable, FAT-SOLUBLE DERIVATIVE of vitamin C, not pure vitamin C. Like SAP, it exists because pure L-ascorbic acid is unstable. THD's lipophilic structure suits the oil phase and skin lipids while resisting oxidation, making it common in premium oil-based serums. It is a precursor expected to convert to L-ascorbic acid in skin; conversion efficiency and effect size are read differently from pure vitamin C and debated in the literature. For "what does vitamin C do?", the main L-ascorbic acid page is useful. This page reads THD as a FORM through fat solubility, stability and conversion. Labels show "Tetrahexyldecyl Ascorbate"; PubChem records it under the trade-name heading "Nikkol VC-IP", but CAS 183476-82-6 confirmed its identity as tetrahexyldecyl ascorbate (CID 10260680, C70H128O10, the tetra-esterified form of ascorbic acid). Klaris reads it as a stable, fat-soluble derivative rather than pure vitamin C, within conversion context and the whole formula.
i. Cosmetic Functions
Frequently Discussed Effects
The following headings summarise areas of effect frequently discussed in the literature; visible results in each area require regular use and a suitable formula.
A Fat-Soluble Vitamin C Derivative
Oil-phase solubility associates it with lipid-based formulas and distribution within the texture.
A Stable Form
It resists oxidation better than pure L-ascorbic acid, underpinning longer-shelf-life messaging.
Tone and Radiance Appearance Context
It appears in antioxidant formulas with messaging about even tone and radiance.
Mechanism
What Happens Within the Skin?
The following points summarise mechanisms from dermocosmetic literature in plain English. Klaris presents them as background information to help readers understand the context, not as medical claims.
Step 1
A Fat-Soluble Vitamin C Derivative
It is a derivative, not pure vitamin C, whose oil-phase solubility associates it with lipid-based formulas and compatibility with skin lipids.
Step 2
Why It Exists: L-Ascorbic Acid Instability
Pure L-ascorbic acid is unstable; THD ascorbate offers a lipophilic, oxidation-resistant alternative to that problem.
Step 3
Stability and Shelf Life
Greater oxidation resistance than pure L-ascorbic acid underpins longer-shelf-life messaging.
Step 4
Precursor Conversion and Debated Efficiency
It is expected to convert to L-ascorbic acid in skin; conversion efficiency and effect size differ from pure vitamin C and remain debated.
Step 5
Tone and Radiance Appearance Context
It appears in antioxidant formulas with messaging about even tone and radiance.
ii. Role in the Formula
How Is It Read on a Label?
THD ascorbate is a fat-soluble precursor expected to convert to L-ascorbic acid in skin. Conversion efficiency and effect size are read differently from pure vitamin C and debated in the literature. Oil-phase compatibility makes it suitable for premium oil-based serums. Reading it alongside the main vitamin C page is useful.
A Closer Look · pH, Stability, Synergy
Like SAP, THD ascorbate is read as a FORM (a derivative), not pure vitamin C. This page leaves "what does vitamin C do?" to the main L-ascorbic acid page and assesses fat solubility, stability and conversion. Solubility distinguishes it from SAP: SAP is water-soluble, whereas THD is fat-soluble, making it suitable for premium oil-based serums and messaging about compatibility with skin lipids. It again exists because pure L-ascorbic acid is unstable; THD is more oxidation-resistant, supporting longer shelf life. The trade-off follows the same logic as SAP: THD is more stable and gentle, but is a precursor expected to convert to L-ascorbic acid in skin. Conversion efficiency and resulting effect size differ from pure vitamin C and remain debated. "Fat-soluble, therefore deeper or stronger" is not an automatic conclusion. There is a reference nuance: PubChem titles THD ascorbate under its trade name "Nikkol VC-IP", but identity was verified with CAS 183476-82-6. Reading only the title could have misled; a CAS cross-check confirmed it. Klaris reads its stable, fat-soluble derivative identity rather than pure vitamin C, conversion context, concentration and the whole formula together.
Typical Concentration Range
1% - 10% (depending on formula context)
Ingredient Family
Vitamins
iii. Sensitivity Advisory
A Note on Extra Care in Context
It is generally described as gentler than pure vitamin C, but a patch test remains a measured approach for sensitive profiles. Assuming this fat-soluble derivative delivers exactly the same effect as pure vitamin C requires context.
A sensitivity advisory is not an instruction for use; where individual health circumstances, pregnancy or known sensitivities are involved, discussing the decision with your doctor may be a more contextual approach.
Common Misconceptions
Frequently Confused Points
Common Belief
THD ascorbate gives exactly the same effect as pure vitamin C.
A More Contextual Reading
THD is a derivative expected to convert to L-ascorbic acid in skin. Conversion efficiency and effect size differ from pure vitamin C and remain debated. The two are assessed as separate forms.
Common Belief
Fat solubility means a deeper or stronger effect than pure vitamin C.
A More Contextual Reading
Fat solubility is a difference in form and oil-phase compatibility. Effect size depends on conversion context and the whole formula; it does not automatically mean "stronger".
Common Belief
A stable, premium form is automatically better.
A More Contextual Reading
Stability and gentleness are advantages, but THD is a precursor requiring conversion. "Stable/premium = better" is not automatic; needs and formula determine the reading.
Common Belief
All vitamin C derivatives, such as SAP and THD, are the same.
A More Contextual Reading
SAP is water-soluble and THD fat-soluble, suiting different water- and oil-phase formula contexts. Form differences affect how each is read within a formula.
Scientific Basis
Sources and Their Scope
The following headings indicate areas of research; they are not citations of a specific publication or confirmation that every statement on this page has been verified. The links provided should be read with their individual scope in mind.
- International INCI / CosIng Database
- Dermocosmetic Research Publications
- Formulation Chemistry Guides
Source Links
- Database RecordPubChem · Tetrahexyldecyl Ascorbate Record (CID 10260680; CAS 183476-82-6, Titled "Nikkol VC-IP")
Database records provide ingredient identity and registration information; on their own, they do not establish the effect of a finished product or its suitability for a profile. Search links are not specific research papers.
iv. Related Ingredients
Ingredients Often Read Together
v. Vitamins Family
Other Ingredients in the Same Family
Explore ingredients in the same functional family to deepen your reading of formulas.
vi. Academy · Related Reading
For a Closer Look
vii. Related Concern Guides
Guides That Include This Ingredient
Klaris · Example Analyses
How Does Tetrahexyldecyl Ascorbate (Fat-Soluble Vitamin C Derivative) Feature
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