What concentration of hyaluronic acid is most effective for the skin?

The hyaluronic acid is a glycosaminoglycan of the extracellular matrix of the dermis playing a major role in its metabolism. Highly hydrophilic, this macromolecule can capture up to 1000 times its weight in water, making it a key agent in maintaining the hydration of skin tissues. Due to its moisturizing properties, the hyaluronic acid is widely used in cosmetics. Its concentration in skincare and haircare products is not strictly regulated, however, it is generally incorporated at rates ranging between 0.01 and 3%. In addition to its effects on the skin, the hyaluronic acid has thickening properties for products, making it difficult to formulate beyond 1% and likely to cause pilling.

Regarding the effectiveness of skincare products containing hyaluronic acid, it is not necessarily correlated with the concentration of the active ingredient. Indeed, an independent study conducted in 2011 with 76 volunteers showed that applying a cream with 0.1% hyaluronic acid salts twice daily hyaluronic acid could significantly increase skin hydration (≈ +10%) and elasticity (≈ +20%) and reduce wrinkle depth (≈ -10%).

Furthermore, we compared two non-independent clinical studies, each focusing on the effects of a serum with 0.4% hyaluronic acid and a serum with 3% hyaluronic acid, respectively. The first study involved 52 volunteers who applied the product daily for four weeks. The second study relied on 22 individuals who used the skincare product twice a day for four weeks. The results obtained regarding skin softness and firmness are compiled in the table below. It should be noted that this summary should be taken with caution as it consists of only qualitative observations, made by the volunteers themselves, and not quantified results. Moreover, this is by no means a comparative study between the two serums, as the participants differed from one study to another.