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Sunday Riley

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

$85·30 ml·~$51/mo to use

Reviewed by SerumTruth Editorial · Price and formula checked July 2026

A well-packaged, disclosed 15% of a stable vitamin C ester for skin that finds L-ascorbic acid too sharp. The derivative carries a thinner evidence record than pure vitamin C, and you pay a prestige price for one active. On comfort and packaging it is a strong pick.

What we like
  • Every active discloses its concentration
  • Air- or light-sensitive actives in protective, opaque packaging
Watch-outs
  • Costly to use, about $51 a month
SerumProof score71 / 100
  • Evidence21 / 30

    Strength of the research behind the key actives

    • Tetrahexyldecyl Ascorbate: moderate evidence

    The average of the key actives’ evidence grades.

  • Potency21 / 25

    Dosed at studied levels, not fairy-dusted

    • Tetrahexyldecyl Ascorbate (15%): dosed at a studied level

    How strongly the actives are dosed, led by the strongest, not how many there are.

  • Delivery & stability16 / 20

    Delivery tech + packaging that protects fragile actives

    • Delivery: standard
    • Packaging: airless, opaque
    • Air- or light-sensitive actives (Tetrahexyldecyl Ascorbate), so packaging is scored.

    Delivery tech plus packaging, and packaging only counts when actives are fragile.

  • Formulation8 / 10

    Disclosure, active breadth, and ingredient generation

    • 1 of 1 actives disclose a concentration
    • 1 key active (breadth credit caps at 3)
    • Current-generation or synergistic: Tetrahexyldecyl Ascorbate

    Disclosure, active breadth, and current-generation or synergistic actives.

  • Value5 / 15

    What a month of use costs vs. the category

    • About $51 per month to use
    • $85 for 30 ml, used about twice a day (about 0.3 ml each time), so a bottle lasts about 1.7 months

    What a month of use costs: full marks at $6 a month or less, the floor at $60 a month or more.

Tap any row to see how its score was built.

Ranks #16 of 27 vitamin c & antioxidants serums we have scored.

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What’s inside

ActiveDisclosedDose
Tetrahexyldecyl Ascorbate15%Studied

15% tetrahexyldecyl ascorbate, an oil-soluble, more stable vitamin C ester, disclosed at 15%, in an opaque bottle with a pump. THD ascorbate is gentler and less pH-fussy than L-ascorbic acid, and the opaque pump suits an oil-phase active that can still oxidise. It is a single vitamin C active rather than a full antioxidant network.

How it’s delivered

DeliveryStandardPackagingAirless, opaque

Air- and light-sensitive actives (vitamin C, copper peptides) lose potency fast in the wrong packaging, so delivery and the bottle are scored, not just what’s on the label.

The actives, explained

What the research says

A serum with this vitamin C ester was linked to a visibly more even tone and less visible sun damage in photographic assessment.

Hydroquinone-Free, Tetrahexyldecyl Ascorbate Antioxidant Serum for Hyperpigmented and Photodamaged Skin to Achieve Skin Health. Journal of Cosmetic Dermatology, 2026. PubMed ↗

A study of the active, not this exact product. What matters for the score is whether this serum uses it at a comparable dose.

Higher-scoring alternatives

Same category, better SerumProof score. Worth a look before you buy.

Revision history
  1. July 11, 2026
    Price and formula rechecked
  2. July 10, 2026
    Review published

Spot an error or a reformulation? Tell us and we will fix it.

Cosmetic information for general education, not medical advice. The SerumProof score reflects our reading of publicly available research and formulation disclosures. See how scoring works.