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Seaweed Types · Ulvan and hydration

Green seaweed: ulvan and hydration.

The one human study we found on any seaweed type is on this page: a hydration study of a cream containing ulvan from green seaweed.

Translucent bright green seaweed fronds drifting in clear shallow water (AI-generated illustration)

In short

  • Ulvans were obtained at 80% carbohydrate purity, with 34% rhamnose and 11% sulfate, and tested at 1% in a hydrating cream.1
  • Objective and subjective evaluation indicated enhanced skin hydration, with high tolerance.1

01

The study

Ulvans were obtained by hydrothermal treatment and a solvent-free concentration step, giving 80% carbohydrate purity, 34% rhamnose, 11% sulfate and a size above 10 kDa.1

Hydrating creams with 1% ulvan and low-mineralization thermal spring water showed a more marked shear-thinning behaviour, which the authors say suggests better spreadability. Objective and subjective evaluation indicated enhanced skin hydration from ulvan and from the thermal spring water, with an additive effect.1

All creams reduced the tightness sensation, and scaling was significantly reduced in the ulvan group, with high tolerance.1

02

How to read it

It was a hand-cream study in healthy volunteers. Some authors work for a seaweed producer and a cosmetics company.1

What we could not confirm

The gaps, stated plainly.

  • Whether ulvan helps people with dry skin conditions. The study used healthy volunteers.
  • Whether the result holds for other creams, doses or body areas.

Questions

Common questions.

What is ulvan?

A polysaccharide from green seaweed. In one study it was prepared at 80% carbohydrate purity, with 34% rhamnose and 11% sulfate.1

Does ulvan hydrate skin?

In one human study, a cream with 1% ulvan was associated with enhanced skin hydration in healthy volunteers. Some authors work for a seaweed producer and a cosmetics company.1

Keep reading

Back to the full guide: Seaweed Types.

More in this guide

Related research

From our library

Sources

Where every claim comes from.

Numbers in brackets link to these entries. Journal entries were read as their PubMed record, and study details come from PubMed, the US National Library of Medicine. See every source on the Research Desk, organised by page.

  1. [1] Marine Drugs (Ingrez and colleagues; some authors are from a seaweed producer and a cosmetics company). Successful combination of ulvans and thermal spring waters from As Burgas (Ourense) for hydrating cosmetic creams in healthy volunteers.

This page is general information drawn from published studies. It is not medical advice and makes no claim about any Vanu Health product. The image is an AI-generated illustration, not a study image. Last updated October 30, 2026.