Hyaluronic acid — not just moisturizing: why cosmetics will not replace fillers

5 facts about the popular ingredient

2025-04-17

Hyaluronic acid (HA) has long been a star of the cosmetic world. It is added to creams, serums, masks, and also used in the form of injectable fillers — all for the sake of moisturizing, elasticity, wrinkle reduction. But a logical question arises: If it is so good, why are fillers still a separate procedure that no cream can replace? Let's break down a few facts from the perspective of molecular chemistry, skin physiology and clinical practice.

Olena Mospanova, PhD, associate professor, pharmacist, cosmetologist, expert in cosmetic chemistry and nutricosmetology, developer of her own cosmetics brand Senoscience, based on scientific research

Fact 1. HA molecule: everything is decided by the size

Hyaluronic acid is a natural polysaccharide synthesized in the human body. Its molecule can be large (high molecular weight) or divided into smaller fragments (low molecular weight).

Both forms are used in cosmetics:

● high-molecular-weight HA (>1000 kDa) forms a moisturizing film on the skin surface, which works as a barrier hydrophilic humectant;

● low-molecular-weight HA (<50 kDa) has the ability to penetrate a little deeper, but as research suggests (Journal of Cosmetic Dermatology, 2020), it does not reach the dermal layer.

Fillers use stabilized (cross-linked) hyaluronic acid, whose molecules are connected by special bridges, such as BDDE. Why exactly is there a need to “cross-link” hyaluronic acid? Because this structure provides:

● high density;

● enzyme resistance;

● long-lasting volume effect.

[…]

Conclusion

Hyaluronic acid is indeed a versatile tool, but not a panacea. Cosmetics provide comfort and care, while fillers provide correction and deep stimulation.

Together they form the perfect synergy for healthy, moisturized and youthful skin.

Literature

1. Journal of Cosmetic Dermatology (2020) — a study of HA penetration.

2. Skin Pharmacology and Physiology (2019) — barrier functions of the skin.

3. FDA reports on the safety of HA-based fillers.

*Full version of the access article in Ukrainian and Russian