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SK-II

Facial Treatment Essence

$185·160 ml·~$121/mo to use

Reviewed by SerumTruth Editorial · Price and formula checked July 2026

The essence that built a cult, and a pleasant fermented hydrator, but the evidence is limited and mostly brand-led while the price is extraordinary for a single-ingredient story. You are paying for the name and the ritual far more than for proven actives.

What we like
  • Every active discloses its concentration
Watch-outs
  • Key actives carry only limited or preliminary evidence
  • Costly to use, about $121 a month
SerumProof score58 / 100
  • Evidence14 / 30

    Strength of the research behind the key actives

    • Galactomyces Ferment Filtrate (Pitera): limited evidence

    The average of the key actives’ evidence grades.

  • Potency21 / 25

    Dosed at studied levels, not fairy-dusted

    • Galactomyces Ferment Filtrate (Pitera) (>90%): dosed at a studied level

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

  • Delivery & stability14 / 20

    Delivery tech + packaging that protects fragile actives

    • Delivery: standard
    • Packaging: clear dropper
    • No fragile actives here, so packaging barely moves the score.

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

  • Formulation6 / 10

    Disclosure, active breadth, and ingredient generation

    • 1 of 1 actives disclose a concentration
    • 1 key active (breadth credit caps at 3)
    • No current-generation or synergy bonus

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

  • Value3 / 15

    What a month of use costs vs. the category

    • About $121 per month to use
    • $185 for 160 ml, used about twice a day (about 1.75 ml each time), so a bottle lasts about 1.5 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 #80 of 84 hydration & barrier serums we have scored.

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What’s inside

ActiveDisclosedDose
Galactomyces Ferment Filtrate (Pitera)>90%Studied

A famous single-ferment essence built on over 90% galactomyces ferment filtrate, branded as Pitera, in a clear glass bottle you shake into your hands. It is a hydrating, conditioning first-step layer aimed at the appearance of a smoother, brighter-looking complexion. It is essentially one ferment blend plus preservation, so there is little else on the label.

How it’s delivered

DeliveryStandardPackagingClear dropper

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

In a small trial, a serum with this ferment filtrate plus other actives was linked to a better look of lingering dark spots after 8 weeks.

The Effectiveness of Galactomyces Ferment Filtrate, Dexpanthenol, and Centella Asiatica Combination Serum in the Treatment of Post-Acne Hyperpigmentation in Subjects with Skin of Color. Skinmed, 2021. 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

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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.