Nucleo Longevity
it

Hyaluronic acid

hyaluronic acid · hyaluronan · sodium hyaluronate

The skin- and joint-hydrating molecule used topically, orally and as a dermal filler.

TypeSupplement / topical / injectable

The grade answers: What does the human evidence support for: Skin hydration & joint comfort?

Grade

C

Limited

The grade rates evidence quality — it is not advice to take or buy.

Class
Glycosaminoglycan
Primary use
Skin hydration & joint comfort
Evidence strength
medium
Last reviewed
2026-07-01

Bottom line

Well established for what it physically does — holding water — with decent evidence for skin hydration (topical/oral) and injectable use. As an ingested 'anti-aging' cure its systemic claims are more modest than the marketing.

What the evidence says

Hyaluronic acid is a natural component of skin and joint tissue that binds large amounts of water. The evidence splits by route: topical and injectable (dermal fillers, some osteoarthritis injections) use is well established for hydration and volume; oral supplementation has a growing set of small trials suggesting improved skin hydration and possibly joint comfort, though absorption and mechanism of ingested HA are debated. There is no systemic longevity evidence. Grade C: real, route-dependent cosmetic and joint benefits, not a longevity intervention.

Key studies

  1. [1]

    Oral hyaluronic acid and skin hydration · RCT

    Small improvements in skin hydration/elasticity.

    Open on PubMed ↗
  2. [2]

    Hyaluronic acid injections for knee osteoarthritis · meta-analysis

    Debated, modest benefit for joint symptoms.

    Open on PubMed ↗
  3. [3]

    Hyaluronic acid biology (review) · review

    Background on its hydration and structural roles.

    Open on PubMed ↗
See all studies on PubMed ↗

Mechanism

A glycosaminoglycan that retains water to maintain tissue hydration and viscoelasticity; ingested HA is broken down and may act partly by signalling rather than direct incorporation.

Safety

Topical and oral use are very well tolerated. Injectable procedures (fillers, intra-articular) are medical acts with procedure-related risks and should be done by professionals.

Dosage context

Oral trials commonly use ~120–240 mg/day over 8–12 weeks. Topical concentration and molecular weight affect performance; injectable use follows clinical protocols.

Examples of application

  • Applied topically in a serum on damp skin, then sealed with moisturiser.
  • Also taken orally (~120–240 mg/day) for skin hydration in trials.
  • Injectable use (fillers) is a medical procedure, professionals only.

From the field

Hyaluronic acid is a rare supplement where the physical mechanism is undeniable — it's just that 'holds water in skin' is a cosmetic claim, not a longevity one. Grade C, and route matters a lot.

Related molecules

Collagen peptidesCPolynucleotides (PDRN/PN)F
How we assign grades → Method