Why does hyaluronic acid pill?

Naturally present in the epidermis and the dermis, hyaluronic acid is essential for skin hydration. Combined with sulfated glycosaminoglycans in the extracellular matrix, it forms a compressible gel that retains water like a sponge, also allowing its circulation and that of dissolved molecules. This property of hyaluronic acid, coupled with its healing and soothing virtues, explains why this active ingredient is frequently used to formulate cosmetic care. However, it should be noted that hyaluronic acid comes in several versions, possessing different molecular weights : low molecular weight (50 - 1000 kDa), intermediate molecular weight (1000 - 1800 kDa) and high molecular weight (> 1800 kDa).

It is often the latter that is affected by the issue of "pilling". This phenomenon, characterised by the formation of small lumps on the skin's surface, can occur immediately after applying a hyaluronic acid treatment or several hours later. While still not fully understood, it is important to note that pilling is completely harmless and does not result from a formulation or product stability issue. Among the hypotheses put forward to explain this inconvenience, we have the large size of hyaluronic acid. By remaining on the skin's surface, this active ingredient forms a non-occlusive film that can interact with other cosmetics applied as part of the routine. The hyaluronic acid treatment can indeed hinder the skin penetration of subsequent products, leading to pilling.

Not to be confused : Pilling and desquamation are different phenomena. Pilling refers to particles of product not absorbed by the skin, while dead skin cells are a result of natural cellular turnover.

Even though the pilling of hyaluronic acid skincare does not indicate skin irritation, it remains nonetheless bothersome. Here are some tips to avoid it without giving up your favourite products:

• Adhere to the order of skincare application : Products in a cosmetic routine should always be applied from the lightest to the thickest texture. Therefore, if your hyaluronic acid comes in the form of a serum, ensure to apply it before your moisturising cream and after other more fluid serums.

• Be patient with your routine : To prevent your products from pilling, it is recommended to wait 30 to 60 seconds between each application. This allows each treatment to be properly absorbed by the skin and reduces the risk of interaction between different cosmetics.

• Cleanse and exfoliate your skin regularly : Unless it's a cleanser, ensure to apply your hyaluronic acid treatment on clean skin, free from excess sebum and daily impurities. When these accumulate, they can mix with the hyaluronic acid and promote the appearance of fluff. The same goes for dead cells, which should be removed weekly with exfoliation.

• Use hyaluronic acid on damp skin : Applying hyaluronic acid serums or creams on damp skin is often recommended to prevent pilling. In addition to promoting skin absorption, this also facilitates application.

• Gently pat the treatment to allow it to penetrate : Overhandling a hyaluronic acid treatment can also lead to pilling. To prevent this, it is best to allow the treatment to penetrate using pressure movements.

• ANDRE P. Hyaluronic Acid and Its Application as a "Rejuvenation" Agent in Cosmetic Dermatology. Seminars in Cutaneous Medicine and Surgery (2004).

• MASSON F. Hyaluronic Acid and Skin Hydration. Annals of Dermatology and Venereology (2010).