Encyclopedia · humectant
Hyaluronic acid
A large water-binding sugar molecule added to some leave-ins and masks; no hair-fibre study was found.
What it is
A long sugar chain found in skin, made by fermentation for cosmetics. It is a cosmetic ingredient. Filler injections near the scalp are a medical procedure and are not covered here.
How it works
The claim that it forms a surface film and binds water is unproven for hair. The idea that large hyaluronic acid cannot enter hair is an expectation from its size, not a tested result.
What the studies show
- No hair-specific study was located.
Side effects and safety
Topical cosmetic use is low-risk.
Bottom line
A marketing ingredient on hair. A small amount does no harm, but there is no evidence it improves hair, and hair has no living cells to plump. Whether low-molecular-weight versions behave differently is untested. We are very unsure of any benefit.
Studies 0
No studies are listed for this page yet.
Related
- GlycerinA cheap water-binding ingredient in nearly every conditioner; no peer-reviewed hair study tests it, and the popular humidity rules are untested.
- PanthenolA small vitamin B5 alcohol that enters the hair cortex and raised break stress in a lab study; the only humectant here with real hair-fibre data.
- Humectants and humidityHair swells and softens with humidity, but the popular rules about glycerin and humidity have not been tested; panthenol is the humectant with the best fibre data.