Aphanothece Sacrum Polysaccharide

Aphanothece sacrum polysaccharide (also known as sacran) is a sulphated polysaccharide extracted from Aphanothece sacrum, a cyanobacterium native to Japanese river environments. It is a large molecular weight compound derived from algal biomass through acid and alkaline treatment.

In skincare formulations, this ingredient functions as an absorbent, emulsion stabiliser, film former and viscosity controller. Its primary mechanism involves creating a gel-like film on the skin surface that retains water, helping to reinforce the skin's natural moisture barrier.

Sacran creates a protective hydrogel-like layer when applied to skin, particularly in the presence of humectants such as glycerin. This film is water-resistant whilst remaining permeable, meaning it can lock in moisture without occluding the skin or preventing normal skin function.

Evidence from animal studies indicates that sacran may also modulate inflammatory pathways, with research showing it can reduce inflammatory markers and swelling in induced dermatitis models. The polysaccharide appears to have some capacity to penetrate inflamed skin more effectively than healthy skin, potentially concentrating where inflammation is present.

Sacran is typically found in serums, moisturisers and barrier-repair products rather than as a standalone treatment. It works well alongside other hydrating and soothing ingredients such as glycerin, niacinamide or centella asiatica. Apply to clean skin and allow the film-forming layer to set before applying additional products. There is no evidence of diminishing returns with regular use.