Product

The Ordinary Ascorbyl Tetraisopalmitate Solution 20% in Vitamin F

20% THD ascorbate in an oil base, for about $20. The Ordinary is refreshingly honest that this is the gentle option, not the strong one.
At a Glance
Recommended

THD ascorbate is an oil-soluble vitamin C derivative. It must convert to active vitamin C in the skin, and the evidence that it does so usefully is weaker than for L-ascorbic acid. In exchange, it is more stable and far less likely to irritate.

The Ordinary is unusually honest about this, describing it as the gentler option and steering experienced users toward direct L-ascorbic acid instead. A brand talking you down from its own product is a good sign.

The oil base suits dry skin and layers well as a final step, and the added Vitamin F (essential fatty acids) supports the barrier. Do not read 20% as equal to 20% pure vitamin C — it is a different molecule.

Key facts

Key activeTHD ascorbate 20%
TextureLightweight oil
Best forDry or sensitive skin; vitamin C beginners
Approximate price$20–$22
FragranceFragrance free

How it works

The Ordinary tells you exactly what this is, which is rare enough to be worth noting.

Their own product page says it "contains an oil-soluble vitamin C derivative that converts into vitamin C once applied," offering "similar benefits with less irritation potential" — and they explicitly steer experienced users toward their direct L-ascorbic acid products instead. A brand talking you down from its own product is a good sign.

20% THD ascorbate for $20 is the value benchmark in this category. Revision charges eight times that for a comparable ingredient.

The oil base suits dry skin and layers well as a final step, and the Vitamin F (essential fatty acids) supports the barrier.

Everyday habits

How to use it
  • When: morning or night.How much: a few drops as one of your last steps. Steps: apply to clean skin; because it is an oil, use it after water-based serums. Sunscreen: vitamin C is not sun protection — follow with SPF in the day. Layering: The Ordinary flags a possible conflict with niacinamide, so consider using them at different times.
Who should be careful+

It is a derivative. The conversion to usable vitamin C in skin is the assumption the whole product rests on, and the evidence for it is much weaker than for L-ascorbic acid.

The oil format will not suit oily or acne-prone skin.

The Ordinary flags a conflict with niacinamide in their own compatibility guidance — worth knowing if you use both.

Do not read "20%" as equivalent to 20% pure vitamin C. It is not the same molecule.

Questions people ask+
Is this as strong as L-ascorbic acid?No. It is a gentle derivative that must convert in the skin, with weaker evidence.
Is it good for oily skin?Less so. The oil base suits dry or sensitive skin better.
Can I use it with niacinamide?The Ordinary flags a possible conflict, so consider using them at separate times.
Is it fragrance-free?Yes. The formula contains no added fragrance.
Where does it go in my routine?As one of the last steps, since it is oil-based.
Full ingredient list+

Coconut Alkanes, Tetrahexyldecyl Ascorbate, Ethyl Linoleate, Coco-Caprylate/Caprate, Simmondsia Chinensis Seed Oil, Solanum Lycopersicum Fruit Extract, Squalane

References+

1. Ascorbyl Tetraisopalmitate Solution 20% in Vitamin F | The Ordinary (https://theordinary.com/en-us/ascorbyl-tetraisopalmitate-solution-20-in-vitamin-f-vitamin-c-100416.html) — Manufacturer page confirming the 20% ascorbyl tetraisopalmitate formulation, its ~$20 (US$20.50) price, its hydrating oil-based positioning, and that The Ordinary frames derivatives as suited to newer users while offering direct L-ascorbic acid for others. 2. Double-blind, half-face study comparing topical vitamin C and vehicle for rejuvenation of photodamage. (https://pubmed.ncbi.nlm.nih.gov/11896774/) — Clinical trial showing an oil-soluble vitamin C (tetrahexyldecyl ascorbate) formulation produced statistically significant improvement in photodamage and new collagen without inflammation, backing the derivative's efficacy and low-irritation profile. 3. Benefits of combinations of vitamin A, C and E derivatives in the stability of cosmetic formulations. (https://www.mdpi.com/1420-3049/17/2/2219) — Confirms ascorbyl tetraisopalmitate is a chemically stable, fat/oil-soluble vitamin C ester derivative used in cosmetic formulations, supporting the page's description of an oil-soluble vitamin C derivative. 4. Photostability and efficacy studies of topical formulations containing UV-filters combination and vitamins A, C and E. (https://pubmed.ncbi.nlm.nih.gov/17614223/) — Study of ascorbyl tetraisopalmitate topical formulations reporting hydration and anti-aging (cell-renewal) effects and reduced skin irritation, supporting the derivative's benefits-with-less-irritation claim. 5. An Open Label Clinical Trial of a Multi-Ingredient Anti-Aging Moisturizer Designed to Improve the Appearance of Facial Skin. (https://pubmed.ncbi.nlm.nih.gov/26151786/) — Clinical trial of a moisturizer containing THD ascorbate that showed significant improvement in fine lines, tone and brightness while being mild and well tolerated, supporting efficacy and low-irritation claims for the vitamin C derivative.