Today one cannot imagine a complete skincare routine without hyaluronic acid (HA). Hyaluronic acid has become a key ingredient in nearly every skincare product, from serums to moisturizers. So, what makes this molecule special? Let’s delve into the science of HA.
What is Hyaluronic Acid (HA)?
Hyaluronic acid is a polysaccharide found throughout our body. The highest percentage of HA is found in the skin dermis, accounting for 50% of the total body hyaluronic acid1. HA is a linear polymer of alternating glucuronic and N-acetylglucosamine disaccharide units (Fig. 1). Its molecular weight depends on the source and can be as high as 20,000 kDa. HA can be low molecular weight (LMHA, 20-300 kDa) and high molecular weight (HMHA, 1000-1400 kDa). LMHA has better skin permeability and can pass through the stratum corneum2.
Hydrating Mechanisms of Hyaluronic Acid
Due to intra and intermolecular hydrogen bond formation, HA molecules form stiffened helical structures in solution. The coiled helical structure could hold up to 1,000 times its weight in water, making it an excellent skin hydrator (Fig. 2)4.
Due to its excellent viscoelasticity, biocompatibility and biodegradability, it has various applications in managing osteoarthritis, wound healing, tissue regeneration, ophthalmology and dermatology5.
Hyaluronic acid in skin rejuvenation
Hormonal changes and exposure to UV radiation cause pre-mature skin aging and are associated with reduced collagen synthesis, degradation, moisture loss and disturbed HA homeostasis. The normal level of hyaluronic acid declines with increasing age. Various pre-clinical and clinical studies suggest that HA formulations rejuvenate the skin due to their anti-aging, anti-wrinkle, antioxidant, hydrating, collagen-stimulating, anti-erythematic, and skin augmentation properties6.
To conclude, the antioxidant, anti-aging and moisturizing benefits of HA make it a superb choice for skin rejuvenation.
References
(1) Papakonstantinou, E.; Roth, M.; Karakiulakis, G. Hyaluronic Acid: A Key Molecule in Skin Aging. Dermato-Endocrinology. Landes Bioscience 2012. https://doi.org/10.4161/derm.21923.
(2) Essendoubi, M.; Gobinet, C.; Reynaud, R.; Angiboust, J. F.; Manfait, M.; Piot, O. Human Skin Penetration of Hyaluronic Acid of Different Molecular Weights as Probed by Raman Spectroscopy. Skin Research and Technology 2016, 22 (1), 55–62. https://doi.org/https://doi.org/10.1111/srt.12228.
(3) Lierova, A.; Kasparova, J.; Filipova, A.; Cizkova, J.; Pekarova, L.; Korecka, L.; Mannova, N.; Bilkova, Z.; Sinkorova, Z. Hyaluronic Acid: Known for Almost a Century, but Still in Vogue. Pharmaceutics. MDPI April 1, 2022. https://doi.org/10.3390/pharmaceutics14040838.
(4) Necas, J.; Bartosikova, L.; Brauner, P.; Kolar, J. Hyaluronic Acid (Hyaluronan): A Review; 2008; Vol. 53.
(5) Price, R. D.; Berry, M. G.; Navsaria, H. A. Hyaluronic Acid: The Scientific and Clinical Evidence. Journal of Plastic, Reconstructive and Aesthetic Surgery. October 2007, pp 1110–1119. https://doi.org/10.1016/j.bjps.2007.03.005.
(6) Bukhari, S. N. A.; Roswandi, N. L.; Waqas, M.; Habib, H.; Hussain, F.; Khan, S.; Sohail, M.; Ramli, N. A.; Thu, H. E.; Hussain, Z. Hyaluronic Acid, a Promising Skin Rejuvenating Biomedicine: A Review of Recent Updates and Pre-Clinical and Clinical Investigations on Cosmetic and Nutricosmetic Effects. International Journal of Biological Macromolecules. Elsevier B.V. December 1, 2018, pp 1682–1695. https://doi.org/10.1016/j.ijbiomac.2018.09.188.
