Humectant

Calothrix Crustacea

INCI: CALOTHRIX CRUSTACEA

Reviewed by Kate · Last updated 2 Jun 2026

A marine-derived humectant that draws moisture into the skin

Best For Skin Types

All, Dry, Combination, Sensitive

Addresses

Dryness, Hydration, Barrier repair

Usage Frequency

Daily

What Is Calothrix Crustacea?

Calothrix Crustacea is a cyanobacterium (blue-green algae) sourced from marine environments. In skincare, it functions primarily as a humectant and skin conditioning agent, working to improve the skin's moisture-binding capacity.

As a natural extract, it contains polysaccharides and other water-binding compounds that help the skin retain hydration. It is typically used in concentrations that support overall skin hydration without disrupting the skin barrier.

How It Works

Calothrix Crustacea works as a humectant by drawing water from deeper skin layers and the environment into the epidermis. Its polysaccharide content forms a moisture-binding matrix on the skin surface, helping to reduce transepidermal water loss.

This mechanism is particularly useful in formulations designed to improve hydration without occlusion, making it suitable for layering with other actives or for use under moisturisers.

Clinical Evidence & References

Research specifically on Calothrix Crustacea in skincare is limited. The ingredient has been used in cosmetic formulations based on its established humectant properties and traditional use in marine-derived skincare, but robust clinical studies in humans are not widely published.

Evidence for related marine polysaccharides suggests similar ingredients can improve skin hydration and texture when used consistently. More targeted research on this specific extract would help clarify its efficacy profile.

How to Use

Calothrix Crustacea is typically incorporated into serums, hydrating toners, and lightweight moisturisers. For best results, apply to damp skin to maximise the humectant effect, then seal with an occlusive moisturiser if your skin is very dry. It can be used daily and layers well with other hydrating or active ingredients.

Safety & Precautions

Generally well-tolerated across skin types. As a natural marine extract, those with shellfish or iodine sensitivities should patch test first.

Frequently Asked Questions

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