What allantoin is?
Allantoin is a raw material that occurs as a white crystalline powder that is poorly soluble in water.
This molecule is the end product of the oxidative process of uric acid and is naturally present in both animals and plants. For example, it is found in the leaves of Symphytum officinale (comfrey major), the bark of Aesculus hippocastanum (horse chestnut), the leaves of Coffea arabica (coffee) and soya beans. In the latter plants, allantoin, together with other ureides, represents the primary route of nitrogen transport in the body.
What are the effects of allantoin?
The effects of allantoin in cosmetic use are recognised to the extent that it has been included in the US (USP), European (European Pharmacopoeia), and British (British Pharmacopoeial Codex) pharmacopoeias as a dermatological agent.
The American drug agency, FDA (Food and Drug Administration), has classified allantoin as a skin-protective agent, and several studies in the literature highlight its re-epithelialising and smoothing effects, which minimise the signs of ageing.
What actions allantoin performs?
Depending on the concentration of use, this molecule performs different actions on the epidermis: at lower concentrations it manifests moisturising and soothing effects, while at higher concentrations it performs a keratinolytic action, which consists of the degradation of certain elements that make up the stratum corneum, the outermost layer of the skin, favouring the physiological cell renewal cycle.
Several studies have shown that conveying this molecule within vesicular systems (such as glycosomes or liposomes) exponentially increases the beneficial effects of allantoin compared with formulations in which it is found free.
L. Manca et al. Combination of argan oil and phospholipids for the development of an effective liposome-like formulation able to improve skin hydration and allantoin dermal delivery, International Journal of Pharmaceutics, Volume 505, Issues 1-2, 2016.
C. R. Harding et al. Dry skin, moisturization and corneodesmolysis, in International Journal of Cosmetic Science, 2000.
A. KAPUŚCIŃSKA et al. The use of urea and its derivatives in the cosmetics industry (PDF), in Chemik, vol. 68, n. 2, 2004.