Lash serum ingredients

Hyaluronic Acid (Hydroxypropyl Trimonium Hyaluronate)

Cationic hyaluronic acid · Film-forming humectant

Written by the Re:Cosm team · Last reviewed September 23, 2026 · Cosmetic information, not medical advice

In short: A modified hyaluronic acid with a positive charge, engineered to bind to hair fibres. It locks moisture onto the lash and forms a light protective film.

What it is

Hyaluronic acid is a sugar-based molecule the body uses to hold water in skin and joints. In skincare it is prized as a humectant. Standard hyaluronic acid, however, carries a negative charge, and so does the surface of hair, especially damaged hair. Like charges repel, so plain hyaluronic acid does not stay on hair for long.

Hydroxypropyl Trimonium Hyaluronate solves that. It is hyaluronic acid modified with a positively charged group, which lets it cling to the negatively charged lash surface.

What it does on lashes

Once bound, it holds moisture at the surface of the lash and forms a thin, flexible film. That film helps lashes stay hydrated through the day and softens the friction of mascara, cleansing and curling. Paired with panthenol, which works inside the hair shaft, it covers hydration from both directions.

Where it sits in the Re:Cosm formula

Re:Cosm Lash Conditioning Serum has 29 ingredients, and this page covers one part of that formula: a prostaglandin-free, fragrance-free and oil-free peptide serum made in Korea by Kolmar Korea. Every ingredient and the job it does is decoded on the lash serum ingredients guide, and the full label is on the product page.

Common questions

Is hyaluronic acid good for lashes?

Yes, especially in its cationic form, which binds to the lash and holds moisture there instead of washing off.

What is hydroxypropyl trimonium hyaluronate?

A positively charged derivative of hyaluronic acid designed for hair care. The positive charge helps it attach to hair fibres.

Will hyaluronic acid make lashes sticky?

Not at the levels used in a lash serum. It dries to a light, invisible film.

Other ingredients in the formula

Also worth reading: lash serum ingredients to avoid and what prostaglandin-free means.

Sources and standards

Ingredient facts are checked against our published formula and the sources below. We describe how lashes look and feel, never growth: that is a drug claim, and our serum is a cosmetic.

See the whole formula

Prostaglandin-free. Fragrance-free. Oil-free. Every ingredient published.

View Lash Conditioning Serum