Hyaluronic Acid (HA)
Skincare ingredient, decoded — every claim sourced.
What it is
A humectant that draws and holds water in the upper skin layers, leaving skin feeling plumper and more hydrated. It is naturally present in your own skin.
How it works
Hyaluronic acid is a glycosaminoglycan (a long sugar chain) that the skin makes on its own; about half of the body's total HA sits in the skin, mostly in the dermis. Its sugar backbone carries many hydroxyl groups that form hydrogen bonds with water, letting it bind and hold moisture in the spaces between skin cells. Its strong water-binding is on the order of roughly 0.7-2 grams of water per gram (the popular "holds 1,000 times its weight" line is marketing shorthand, not a measured figure). On skin it acts mainly as a humectant: it pulls water into the stratum corneum and upper epidermis, which temporarily improves the look of smoothness and suppleness and softens the appearance of fine lines. Lower-molecular-weight HA reaches a little deeper than large molecules (very small forms have been detected in the deeper epidermis), which is one proposed reason it is linked to a greater smoothing effect on the surface. Because the skin's own HA gradually declines and breaks down with age, replenishing it on the surface helps restore the skin's water content and look rather than rebuilding the skin's underlying structure.
Works well with
GlycerinNiacinamideCeramidesPeptidesVitamin C (Ascorbic Acid)Retinol (eases dryness)
Introduce carefully alongside
No true chemical incompatibilities; apply to damp skin and seal in dry climates to avoid a tight feel
Who should take care
Almost everyone tolerates it, including sensitive, acne-prone and rosacea-prone skin. In very dry climates or low humidity, applying pure HA to a dry face can draw water from deeper skin and feel tightening, so apply it to damp skin and seal with a moisturizer on top. People with a known allergy to a specific HA product or its other ingredients should avoid that product.
🔒 IN THE APP
The dose that actually works — and is it right for your skin?
The concentration that actually makes a difference, and whether this fits YOUR skin profile, lives in the MHS BLOOM app.
Sources
- Pavicic et al. (2011), Efficacy of cream-based novel formulations of hyaluronic acid of different molecular weights in anti-wrinkle treatment, J Drugs Dermatol — 0.1% HA improved skin hydration and elasticity; 50 and 130 kDa forms gave the greatest improvement in wrinkle depth
- Papakonstantinou et al. (2012), Hyaluronic acid: A key molecule in skin aging, Dermatoendocrinol (PMC) — skin holds about half of the body's HA; water-binding role; age-related decline and fragmentation
- Zanchetta, Scandolera & Reynaud (2025), Hyaluronic Acid in Topical Applications: The Various Forms and Biological Effects of a Hero Molecule in the Cosmetics Industry, Biomolecules — molecular-weight penetration ranges and ~0.7-2 g water per g binding capacity
- Cosmetic Ingredient Review (CIR), Safety Assessment of Hyaluronates as Used in Cosmetics (Scientific Literature Review, Oct 5, 2022) — highest reported concentration of use 7.5% (Sodium Hyaluronate, leave-on face/neck, 2021 survey); concluded safe in the present practices of use and concentration; dermal-penetration data by molecular weight (20-50 kDa form reached ~100 µm into the epidermis)
This is not medical advice at all — cosmetic information only. Not suitable during pregnancy or breastfeeding; always consult your doctor.