Allantoin: what are its benefits for the hair?

Allantoin serves to both regulate the inflammatory process, and to soothe scalp irritations and redness. It plays a role in inhibiting COX-2, a cyclooxygenase that contributes to the production of prostaglandins, which in turn are responsible for some of the symptoms of inflammation.

Scientific studies have also shown that allantoin interferes with the activation of NF-κB, a protein involved in the immune response, at the level of p65 transactivation. Several studies have demonstrated that specific phosphorylation reactions lead to post-translational modifications that could influence the transactivation potential of p65.

This study suggested that allantoin could inhibit these phosphorylation reactions and be responsible for the inactivation of NF-kB. Thus, it could help to reduce inflammation and soothe the scalp.

Allantoin aids in softening the stratum corneum by promoting the removal of dead cells. Allantoin eliminates corneocytes by loosening theintercellular cementor desmosomes (protein bridges) that maintain the adhesion of corneocytes to each other. It facilitates their renewal, which replaces the dead cells present on the scalp surface and prevents pore blockage. In this case, allantoin can be beneficial for individuals suffering from dandruff or even scalp crust.

Several studies have mentioned that allantoin possesses moisturising properties and is often used in creams or lotions as a hydrating agent. However, its mode of action is not detailed in scientific literature. Its hydrating potential could be explained by the fact that it is a water-soluble humectant ingredient: it helps to increase the water content of cells by combating transepidermal water loss in the dermis. Thus, it helps to combat a dry scalp and prevent inflammation. Allantoin is also effective in moisturising hair by creating a protective layer on the surface of the cuticle, helping to maintain their shine.

An overproduction of sebum due to hyperactivity of the sebaceous glands can cause scalp itchiness and make the hair greasy. It is often read that allantoin could counteract this issue, but is this really the case?

Allantoin is an active ingredient used in the formulation of deodorants. It has often been suggested that it has the ability to regulate sebum secretion and eliminate excess in cases of hyperseborrhea. However, this property has never been confirmed in scientific studies, and therefore it is not possible to assert that allantoin possesses sebum-regulating properties.

To reap its hair benefits, one can adopt a routine composed of allantoin-based products. Notably, there are many soothing shampoos available for sensitive scalps that contain allantoin. They help to soothe and reduce scalp itching, caused by environmental factors such as pollution or stress.

Allantoin is also found in conditioners or hair masks to soften the hair and make it shine. Allantoin is an extremely beneficial ingredient for all hair types and is often used in children's hair products. To benefit from its advantages, it is recommended to favour treatments where the concentration of allantoin is at least 0.5% of the total weight.

• IGILE G. O. & al. Rapid method for the identification and quantification of allantoin in body creams and lotions for regulatory activities. International Journal of Current Microbiology and Applied Sciences (2014).

• SAVIĆ V. L. & al. Comparative study of the biological activity of allantoin and aqueous extract of the comfrey root. Phytotherapy Research (2015).

• DINICA R. M. & al. Allantoin from valuable romanian animal and plant sources with promising anti-inflammatory activity as a nutricosmetic ingredient. Sustainability (2021).