Algin
Allowed
Sodium Alginate · Alginate · Alginic Acid · Algin
Sodium alginate, a purified polysaccharide from the cell walls of brown seaweed. It is a hydrocolloid: it thickens water, forms a light breathable film and helps a cream stay emulsified. It is in our own Moisturose.
- What it does
- Emulsifiers, Thickeners & film
- Our take
- We are naming this one ourselves because it is in our product and because the acne clinics' list includes it. Algin is a sugar polymer, not a lipid. It is fully water-soluble, it has no oil phase to partition into sebum, and the mechanism that makes an oil or a wax block a follicle does not apply to it. It is used at gum levels, a few tenths of a percent, and in Moisturose it sits eleventh of twenty-eight ingredients.
- What we look for
- 0.1-0.5%, gum levels
- Best for
- Dryness & hydration
- Skin types
- Any skin · Oily · Blemish-prone · Dry · Sensitive
- Pairs with
- Fine with everything. It is a texture ingredient, not an active.
watch the stacking
No stacking concern. Gums do not accumulate across a routine the way an active or a preservative does.
where we disagree
The pore-clogging lists carry algin, alginate, alginic acid and sodium alginate as four separate entries, alongside roughly sixty other algae and seaweed names. That block is organised by source organism, not by chemistry: everything that comes out of seaweed is on it. We think that is the weakest part of those lists, and we said so before this ingredient became our problem. The distinction we draw is between a whole algae extract, which carries the lipids, sterols and unstandardised botanical fraction the assays actually looked at, and a purified polysaccharide isolated out of it. It is the same distinction we make between squalane and squalene, and between fractionated caprylic/capric triglyceride and coconut oil. We do not carry the flag through to the purified gum.
find it in
What we read
- EU CosIng; comedogenicity literature reviewed against purified alginate · reviewed Sep 2026
Every other ingredient, with the same treatment.
