The most quietly powerful hydrator in skincare — a molecule that holds water like nothing else, and hydrates where skin needs it most.

---

What it is.

Hyaluronic acid is a polysaccharide naturally produced by your body. It lives in your skin, joints, and connective tissue — binding water and keeping everything hydrated, cushioned, and pliable.

Each hyaluronic acid molecule can hold up to a thousand times its weight in water. In skin, that translates to deep, lasting hydration — if it's delivered correctly.

Molecular weight matters. The low-molecular-weight hyaluronic acid used across the Skin Theorie range is small enough to travel beyond the surface and hydrate the deeper layers of skin — where suppleness is held, not just felt.

What it does.

Immediate plumpness

As hyaluronic acid binds water through the skin, it creates a smoothing, plumping effect. Fine lines that come from dehydration visibly soften.

Deep hydration

Low molecular weight HA penetrates deeper layers and hydrates from within. This is where lasting suppleness comes from — the kind that holds through the day, not just the first hour.

Reduces dehydration lines

Most fine lines look more pronounced when skin is dehydrated. Consistent hyaluronic acid smooths them visibly without any aggressive intervention.

Supports every skin type

HA is non-irritating, non-comedogenic, and well-tolerated by even the most reactive skin. There's almost no skin type that doesn't benefit.

Who it's for.

Dry skin. Dehydrated skin (even oily skin can be dehydrated). Mature skin where natural HA production has declined. Sensitive skin that can't tolerate aggressive actives. Anyone whose skin feels tight by midday.

Pregnancy-safe. Breastfeeding-safe. Layer-friendly with every other active in your routine.

In the range.

Hyaluronic acid appears in two Skin Theorie formulas — carrying hydration through both day and night.

Radiance Lux Day Cream — hyaluronic acid with antioxidant botanicals, for hydration that holds through SPF and makeup, all day.

Stillness Lux Night Cream — hyaluronic acid layered with nourishing butters, plumping and replenishing skin overnight.