Every vitamin C serum I’ve tried before this one oxidized into orange juice within two weeks. Prequel bets big on tetrahexyldecyl ascorbate — a fat-soluble C that doesn’t die the moment it hits air.
It’s 15% THD, which sounds aggressive, but the molecule penetrates deeper than L-ascorbic acid and stays active for hours, not minutes. That’s the whole point.
This is a $28 serum. No frills. The claim that made me bite: it’s supposed to deliver brightening without the sting or the shelf-watch anxiety.
No water in the formula
Means less degradation. It’s suspended in a blend of oils and glycerin.
Deep lipid-layer delivery
THD doesn’t just sit on top — it slips into the lipid barrier. Less waste.
Low irritation profile
I didn’t get that “acid tingle” everyone says is normal. It felt like nothing.
Photo: Mockup Free / Unsplash
No fluff. Here’s what’s doing the work. The hero is THD, but the supporting cast pulls weight too — specifically the ferulic acid and vitamin E that stabilize the whole thing.
- Tetrahexyldecyl Ascorbate 15%: Fat-soluble C that penetrates deep and resists oxidation
- Ferulic Acid: Boosts photoprotection and slows C degradation
- Tocopherol (Vitamin E): Synergizes with C for collagen support
- Sodium Hyaluronate: Adds hydration without messing with the oil base
Photo: Sonia Roselli / Unsplash
It’s an oil. Not greasy — think lightweight body oil, not frying oil. Absorbs in about 20 seconds. Leaves a faint sheen that sinks in by minute five.
Week two: I noticed my sunspots didn’t darken after a weekend of forgetting sunscreen. That’s the THD doing long-haul work. One weird thing — it smells faintly of play-doh. No fragrance, just raw ingredients.
Photo: El S / Unsplash
Three weeks in: my overall tone is more even — not dramatically brighter, but the dullness is gone. One stubborn dark spot near my jaw is visibly lighter. Texture didn’t change. Pores are the same.
Photo: Vedansh Agrawal / Unsplash
This serum won’t make you look airbrushed, but it will keep your vitamin C from turning into regret by week three. It’s a workhorse, not a show pony.