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La Roche-Posay

Hyalu B5 Serum

$40·30 ml·~$24/mo to use

Reviewed by SerumTruth Editorial · Updated July 2026

A pharmacy-standard hydrator that does the comfort job well and is priced above the bargain HA serums for the finish and the brand. Be clear on what it is: the look of hydration and calm, not anti-aging. If you want a reliable, fuss-free hydrating layer, it delivers.

SerumProof score70 / 100
  • Evidence21 / 30

    Strength of the research behind the key actives

    • Hyaluronic Acid: moderate evidence
    • Panthenol: moderate evidence
    • Madecassoside: moderate evidence
    • Score is the average of the key actives’ evidence grades.
  • Potency20 / 25

    Dosed at studied levels, not fairy-dusted

    • Hyaluronic Acid: dosed at a studied level
    • Panthenol: dosed at a studied level
    • Madecassoside: present, but below a studied dose
    • Potency tracks 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: tinted glass
    • No fragile actives here, so packaging barely moves the score.
  • Formulation4 / 10

    Disclosure, active breadth, and ingredient generation

    • 0 of 3 actives disclose a concentration
    • 3 key actives (breadth credit caps at 3)
    • Current-generation or synergistic: Panthenol, Madecassoside
  • Value11 / 15

    What a month of use costs vs. the category

    • About $24 per month to use
    • $40 for 30 ml, used about twice a day (about 0.3 ml each time), so a bottle lasts about 1.7 months
    • Band: $6/month or less earns full marks, $60/month or more hits the floor.

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Where to buy at La Roche-Posay

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What’s inside

ActiveDisclosedDose
Hyaluronic Acidn/aStudied
Panthenoln/aStudied
Madecassosiden/aLight

Two molecular weights of hyaluronic acid with panthenol (vitamin B5) and a little madecassoside, in a tinted dropper bottle. It is a hydration and comfort serum aimed at the appearance of plumper, calmer-looking skin, not a tone or fine-line treatment. None of the actives are fragile, so packaging is not a concern here. It layers cleanly under moisturiser and sunscreen.

How it’s delivered

DeliveryStandardPackagingTinted glass

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

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.