Healing is a physiological process of skin tissue repair. Its mechanism can range from a few weeks to a few months. Various solutions are proposed to accelerate this process. Among them is the use of allantoin. Let's explore the results from the scientific literature.
Allantoin, an active ingredient that accelerates skin healing?
The healing process, in brief.
When the skin is damaged, due to an injury or acne for instance, it responds by initiating several defense mechanisms to combat inflammation including healing. This complex process consists of four phases: hemostasis, inflammation, proliferation, and tissue resolution.
The first phase of hemostasis begins as soon as the wound appears, with vascular constriction and the formation of a fibrin clot. The clot and the surrounding wound tissue release pro-inflammatory cytokines and growth factors, such as transforming growth factor (TGF)-β, platelet-derived growth factor (PDGF), fibroblast growth factor (FGF), and epidermal growth factor (EGF).
As soon as the bleeding is under control, we observe a movement of inflammatory cells migrating into the wound (chemotaxis), promoting the inflammatory phase characterized by the infiltration of neutrophils, macrophages, and lymphocytes.
The proliferative phase typically follows and overlaps with the inflammatory phase, characterized by a process of re-epithelialization, or the regeneration of the epidermis, which occurs through the activation of keratinocytes, the constituent cells of the epidermis. These cells are located at the periphery of the wound and will multiply and migrate towards the injury site by interacting with the components of the extracellular matrix.
The final stage is tissue resolution characterized by the formation of new blood vessels (angiogenesis) such that the vascular density of the wound returns to normal.
What role does allantoin play in wound healing?
For over 80 years, allantoin has been used in cosmetic and pharmaceutical preparations for therapeutic purposes. It has often been cited in literature for its numerous pharmacological properties : moisturizing, soothing, keratolytic, and wound healing booster. However, the mechanism of action of allantoin on the wound healing process is still not well understood. Let's explore the results of a scientific study together.
A study conducted in 2010 aimed to identify the healing profile induced by allantoin. For this purpose, allantoin was incorporated at 5% into an emulsion and the experiments in vivo were conducted on injured rats. The results obtained showed that in both the rats treated with the 5% allantoin lotion and the control group of rats, the healing phase proceeded well. However, for the group of rats treated with the allantoin lotion, this healing process occurred more rapidly.
Indeed, as early as the third day, a reduction in inflammatory cells and an early deposit of collagen is observed. Collagen stimulates and recruits immune cells and fibroblasts, promoting wound healing. For the control group, collagen deposition begins on the seventh day and the reduction of inflammatory cells starts from the fourteenth day.
These results suggest that allantoin promotes the healing process. It is hypothesized that it modulates the inflammatory response by potentially inhibiting the chemotaxis of inflammatory cells at the wound site. The early deposition of collagen induced by allantoin suggests that it plays a role in fibroblastic proliferation and the synthesis of extracellular matrix, a major element in the structure and organization of skin tissues during healing.
Typically, allantoin is used at a concentration of 2% and mixed with other substances in formulations, but in this case, a concentration of 5% was used to measure the effectiveness of allantoin alone on the healing process. Although these results seem promising, it is difficult to conclude that allantoin accelerates skin healing. It would intervene during the inflammatory phase, but again it is difficult to assert with this study whether, in addition to its healing power, allantoin would possess anti-inflammatory properties. Further clinical studies need to be conducted to confirm its role in this biological process and its mechanism of action.
SILVA-BARCELLOS N. M. & al. Profile of wound healing process induced by allantoin. Acta Cirúrgica Brasileira (2010).