What are the potential risks associated with hyaluronic acid?

When applied topically, hyaluronic acid is an active ingredient known for its excellent tolerability.

It is suitable for all skin types, including sensitive, atopic, or redness-prone skin. Moreover, this active ingredient is neither irritating, nor allergenic, nor photosensitizing, making it a safe option in any season, even before sun. Furthermore, European cosmetic regulations do not impose a maximum concentration for this ingredient. In practice, formulations typically use the hyaluronic acid at concentrations ranging from 0.1% to 3%, depending on the desired effect. Whether incorporated into a serum, cream, or mask, it can be used daily with confidence.

Side effects associated with hyaluronic acid are very rare and limited to mild redness that may correspond to an allergic reaction. A study conducted by TORT and KARAKUCUK assessed the tolerability of various serums containing 0.5%, 1%, or 2% of hyaluronic acid of low molecular weight (400 kDa). These serums were applied under occlusion to the forearms of 15 volunteers for durations of 30 minutes, 72 hours, 96 hours, and 7 days. No signs of irritation were observed in any participants, even with the higher concentration formulations or after a week of occlusion. Although the small sample size limits the scope of the conclusions, this study is reassuring regarding the good tolerability of hyaluronic acid.

Hyaluronic acid present in topical skincare products is also considered safe for pregnant or breastfeeding women. A review by the Scientific Committee for Consumer Safety (CSSC), an independent scientific committee managed by the European Commission, compiled data from about ten studies on the safety of using hyaluronic acid during pregnancy. These studies were conducted on rats or rabbits and, in the vast majority of cases, no side effects or fetal abnormalities were observed. However, in one trial where rats received up to 60 mg/kg body weight of a 1 % hyaluronic acid solution by subcutaneous injection, nodular hyperplasia of the reticular zone cells was present in the adrenal glands of the treated mothers.

It is important to put this result into context: this finding comes from a single animal study in which the product was administered by injection rather than topically. To date, hyaluronic acid has been used for several decades in cosmetic products, with no reported adverse effects in pregnant or nursing women, nor in their children. Although no clinical trials have been conducted in pregnant women for obvious ethical reasons, the available data and its long-standing use support its good tolerability. As always, however, it remains advisable to consult a healthcare professional before any application, especially on damaged skin or simply when in doubt.

Although hyaluronic acid is generally well tolerated, it remains advisable to exercise caution when using any new cosmetic product, including those containing this active compound.

Indeed, the complete formulation of a skincare product may include other ingredients capable of causing reactions on the skin, particularly in those with sensitive or allergy-prone skin, such as fragrances, essential oils, or certain alcohols. To minimize any risk, it is therefore recommended to conduct a preliminary test on a small area of skin, such as the inside of the wrist or elbow, by applying a small amount of the product and observing the reaction over 24 to 48 hours. If redness, itching, burning sensations, or any other discomfort arises, do not apply the product to the face or body, as this indicates your skin does not tolerate it.

In aesthetic medicine, hyaluronic acid is renowned for delivering excellent results, particularly in softening wrinkles, firming facial contours, or reducing the visibility of scars. Moreover, according to the French National Agency for the Safety of Medicines and Health Products (ANSM), adverse effects related to injections of hyaluronic acid affect only about 0.1 to 1% of individuals. The most common are swelling, redness, itching, and mild bruising that disappear within a few days. Regarding postoperative complications, they remain rare but can occur. These mainly involve bacterial infections and tissue necrosis. Such side effects must be addressed promptly to prevent long-term consequences.

Contraindication : Hyaluronic acid injections are contraindicated in pregnant or breastfeeding women, in individuals taking anticoagulants, in those with an autoimmune disease, or in those presenting with a skin infection.