National Hyaluronic Acid Day is observed worldwide every January 21 to recognize the benefits of hyaluronic acid, a key ingredient in skincare known for its hydrating and anti-aging properties. The holiday was launched in 2022 by La Roche-Posay, a dermatologist-recommended skincare brand, to educate consumers about the advantages of hyaluronic acid for all skin types and to provide tips for its proper use. Hyaluronic acid, which occurs naturally in the human body, plays a vital role in wound healing and is widely used in moisturizers, serums, and facial masks due to its ability to absorb and retain water. Celebrations often include trying out hyaluronic acid products, with many brands offering discounts, and sharing information on social media using the hashtags #NationalHyaluronicAcidDay and #NationalHADay. The holiday aims to highlight the importance of this ingredient in skincare routines and promote its extensive benefits.