How much THD ascorbate do you need? 1%+

What THD ascorbate percentage is effective?

The floor comes from the supplier's own placebo-controlled work, so weigh it as such: NIKKOL ran 1%, 2% and 3% tetra-isopalmitoyl ascorbic acid creams against placebo, split-face on the periorbital area, 23 women per group for 8 weeks, and all three reduced wrinkles by visual grading and topography, the effect profile differing by concentration (Yokota 2022).

Is more than 1% THD ascorbate better?

Nobody has measured it: no published dose comparison sets a ceiling for THD ascorbate, so a percentage above 1% is above the trials' floor, not above a measured maximum. The highest dose tested in leave-on use was 30% in a serum with other antioxidants and prebiotics (Maloney 2026), and it was tolerated.

No published dose comparison sets a ceiling for thd ascorbate. A declared percentage above 1% is above the trials' floor, not above a measured maximum: the trials say from 1% it works, and say nothing about whether more does more.

What does the THD ascorbate percentage on a label tell you?

A name that states a percentage ("THD Ascorbate 1%") is the only amount a cosmetic label ever declares, so it is the one number that can be read against the trials: at or above the 1% floor, or below it.

A name without a percentage leaves the position. The rules make a brand list ingredients in descending order of amount down to 1%, and in any order below it, so thd ascorbate above the 1% line is at least 1% and thd ascorbate below it can be any trace the brand likes. The floor the trials worked from is 1%, and a position alone cannot tell you whether a label reaches it.

The THD ascorbate percentages in our catalogue

2 labels carry it without a number, so the position is all there is:

• Paula's Choice Clinical 0.3% Retinol + 2% Bakuchiol TreatmentTHD Ascorbate sits 16th of 67, above the 1% line; the label does not say how much, and the trials worked from 1%.
• Medik8 Crystal Retinal 6THD Ascorbate sits 20th of 47, below the 1% line; the label does not say how much, and the trials worked from 1%.

Read on

• THD Ascorbate: the glossary page what it does, who it suits, where it fits
• THD Ascorbate vs Niacinamide
• THD Ascorbate vs Vitamin C (LAA)
• THD Ascorbate vs Retinol
• THD Ascorbate vs Retinal
• THD Ascorbate vs Hydroxypinacolone Retinoate
• THD Ascorbate vs Retinyl Palmitate

Other actives with a dose the trials pinned:

• Niacinamide 2%+
• Vitamin C (LAA) 5%+
• Retinol 0.075 to 0.3%
• Salicylic acid (BHA) 0.5%+
• Lactic acid 8%+
• Glycolic acid 5%+
• Retinal 0.05 to 0.1%
• Retinyl Retinoate 0.06%+
• Tretinoin 0.025%+
• Adapalene 0.1%+
• Tazarotene 0.045%+
• Azelaic Acid 15%+
• Sodium Ascorbyl Phosphate 5%+
• Palmitoyl Pentapeptide-4 0.0003%+
• Caffeine 2%+
• Benzoyl Peroxide 2.5 to 5%
• Tea Tree Oil 5%+
• Hydroquinone 4%+
• Bifida Ferment Lysate 10%+
• Thiamidol 0.2%+
• Cysteamine 5%+
• Menthol 0.1 to 5%
• Peppermint Oil 0.5%+
• N-Acetyl Glucosamine 2%+
• Alpha Lipoic Acid 5%+
• Ammonium lactate 12%+
• Acetylated Hyaluronic Acid 0.1%+
• 4-n-Butylresorcinol 0.1%+
• 4-t-Butylcyclohexanol 0.4%+
• Sphingomonas Ferment Extract 2%+