Tetrahexyldecyl Ascorbate (THD Ascorbate)
The premium oil-soluble vitamin C — stable, deep-penetrating, non-stinging, and the gentlest form for sensitive skin and eyes
INCITetrahexyldecyl Ascorbate
- Category
- Antioxidant
- Risk level
- low
- Oil-soluble
- Penetrates the skin's lipid layers better than water-soluble vitamin C forms
- Very stable
- Formulated anhydrous at neutral pH — doesn't oxidise/brown like pure vitamin C
- Tolerability
- The gentlest vitamin C; allergy essentially unheard of; the usual choice for the eye area
- Catch
- Expensive, and results are gradual (8–12 weeks)
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This ingredient may appear under any of these names:
Commonly found in
Possible reactions
- No documented allergic reactions
- No stinging at any concentration
- Excellent stability — doesn't brown like L-ascorbic acid
- Suitable for sensitive and reactive skin
- Pregnancy-safe
Top picks with Tetrahexyldecyl Ascorbate (THD Ascorbate)
Highly rated products that feature Tetrahexyldecyl Ascorbate (THD Ascorbate) in their ingredient list.
Always scan the actual label before use — formulations change.
What is THD ascorbate?
Tetrahexyldecyl ascorbate — THD ascorbate, often sold as BV-OSC — is the most premium vitamin C derivative in skincare. Linking ascorbic acid to four long fatty-acid chains turns the fragile, water-soluble vitamin into a stable, oil-soluble molecule. The result: it doesn't oxidise easily, doesn't sting, and penetrates the lipid-rich skin layers better than water-soluble vitamin C. Inside the skin, enzymes release active vitamin C with a good yield.
The only real downside is cost — it's significantly pricier than L-ascorbic acid, SAP, or MAP — which is why it shows up mainly in premium and dermatologist-led formulas.
Why it's so well tolerated
Because it's formulated in anhydrous (water-free) bases at neutral pH, THD ascorbate avoids both irritation triggers of pure vitamin C (low pH and water-driven oxidation). It's rated safe at cosmetic levels (0.5–10%), and contact allergy is essentially unheard of — even people who react to L-ascorbic acid serums usually tolerate it. It's also the one vitamin C form that works well in oil and balm bases and is the usual pick for the delicate eye area.
The catch is slow onset: like other gentle derivatives, results take 8–12 weeks. It's a long-term investment, not an overnight glow.
How to use it well
- Be patient — 8+ weeks of daily use.
- Morning or evening — stable either way; morning adds antioxidant SPF support.
- Pair with sunscreen.
- Choose it if any L-ascorbic acid irritates you — the gentlest option.
- Great in eye creams and oil-based routines.
Alternatives
- Max potency, lower cost: L-ascorbic acid 10–20% (if tolerated).
- Cheaper gentle derivatives: SAP, MAP.
- Non-vitamin-C brightening: niacinamide, alpha arbutin, azelaic acid.
The bottom line
THD ascorbate is the luxury, low-irritation vitamin C — stable, oil-friendly, eye-area-safe, and tolerated by almost everyone. Pay more and wait longer for gradual results; in return you get the gentlest vitamin C there is.
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