Sunday Riley C.E.O. 15% Vitamin C Brightening Serum dupe

The Ordinary Ascorbyl Tetraisopalmitate Solution 20% in Vitamin F

−77%per oz

Sunday Riley · $40The Ordinary · $18.45

Shared: Tetrahexyldecyl ascorbate
The trade-off: Sunday Riley puts it in a water-based cream-serum, while The Ordinary dissolves 20% of it in a water-free oil with vitamin F (ethyl linoleate) and jojoba, which suits dry skin better than oily.
Sizes: 15 ml against 30 ml

C.E.O. 15% Vitamin C Brightening Serum costs about $40 for 15 ml ($78.86 / fl oz). The dupe below is The Ordinary Ascorbyl Tetraisopalmitate Solution 20% in Vitamin F at $18.45, about 77% less per ounce. Each pair is compared on format, finish and key ingredients, including what the dupe doesn't do.

Brightening serum with tetrahexyldecyl ascorbate, the oil-soluble form of vitamin C that is gentler than pure ascorbic acid, in a light water-based emulsion with squalane and a touch of glycolic acid. For dull, uneven tone.

Amazon prices as of Sep 28, 2026, 1:12 AM ET, subject to change: the price on Amazon at checkout is the one that applies.

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The dupe, side by side

The original

Sunday Riley

C.E.O. 15% Vitamin C Brightening Serum

$40

$78.86 / fl oz

Cost per fl oz

Sunday Riley$78.86 / fl oz

The Ordinary$18.19 / fl oz

$21.55 less at checkout than the original.

Size: Original · Sunday Riley15 ml; Dupe · The Ordinary30 ml
Key ingredients: Original · Sunday RileyTetrahexyldecyl ascorbate, Squalane; Dupe · The OrdinaryTetrahexyldecyl ascorbate, Ethyl linoleate

What matches

Same form of vitamin C: tetrahexyldecyl ascorbate, the oil-soluble ester that converts to vitamin C in the skin and stings far less than ascorbic acid, with squalane on both labels.

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Questions

What is the best dupe for Sunday Riley C.E.O. 15% Vitamin C Brightening Serum?

The Ordinary Ascorbyl Tetraisopalmitate Solution 20% in Vitamin F at about $18.45. Same form of vitamin C: tetrahexyldecyl ascorbate, the oil-soluble ester that converts to vitamin C in the skin and stings far less than ascorbic acid, with squalane on both labels.

How much cheaper is The Ordinary Ascorbyl Tetraisopalmitate Solution 20% in Vitamin F than C.E.O. 15% Vitamin C Brightening Serum?

C.E.O. 15% Vitamin C Brightening Serum costs about $40 for 15 ml, or $78.86 / fl oz. The Ordinary Ascorbyl Tetraisopalmitate Solution 20% in Vitamin F works out at $18.19 / fl oz, roughly 77% less per ounce.

What does The Ordinary Ascorbyl Tetraisopalmitate Solution 20% in Vitamin F do worse than C.E.O. 15% Vitamin C Brightening Serum?

Sunday Riley puts it in a water-based cream-serum, while The Ordinary dissolves 20% of it in a water-free oil with vitamin F (ethyl linoleate) and jojoba, which suits dry skin better than oily.