Skin applications of cannabidiol: sources, effects, delivery systems, marketed formulations and safety

In recent decades, the therapeutic potential of cannabinoids and analogous compounds has been intensively investigated. The endocannabinoid system has already been identified in the skin and, although much remains to be discovered about its contribution and importance for the maintenance of skin homeostasis, it has been increasingly associated as promising for dermatological disorders' management. Cannabidiol (CBD), the main non-intoxicating phytocannabinoid in cannabis, has been shown to have hydrating, sebostatic, antipruritic, antimicrobial, anti-inflammatory, antioxidant, wound healing, photoprotective, anti-fibrotic and antitumoral, as well as modulating hair growth. Thus, CBD has gained attention concerning its application in cutaneous pathologies such as atopic dermatitis, psoriasis, acne, epidermolysis bullosa, systemic sclerosis, seborrheic dermatitis, androgenetic alopecia and cutaneous melanoma, although its bioactivities still lack scientific evidence and some of its mechanisms of action remain to be elucidated. Given its physicochemical characteristics, its topical administration becomes challenging, and it is necessary to develop new technological strategies to overcome the skin intact barrier. This review describes the latest evidence that exists on the application of CBD to the skin, the problems inherent to its chemical structure and that compromise its cutaneous administration, and the different strategies and formulations that have been studied to improve it, also clarifying some CBD-containing cosmetics products that are already available on the market.