Though there is limited research confirming the purported topical benefits of cannabinoids, it is certain that cutaneous biology is modulated by the human endocannabinoid system (ECS). Receptors from the ECS have been identified in the skin and systemic abuse of synthetic cannabinoids, and their analogs, have also been associated with the manifestation of dermatological disorders, indicating the effects of the ECS on cutaneous biology. In particular, cannabidiol (CBD), a non-psychoactive compound from the cannabis plant, has garnered significant attention in recent years for its anecdotal therapeutic potential for various pathologies, including skin and cosmetic disorders. Though a body of preclinical evidence suggests topical application of CBD may be efficacious for some skin disorders, such as eczema, psoriasis, pruritis, and inflammatory conditions, confirmed clinical efficacy and elucidation of underlying molecular mechanisms have yet to be fully identified. This article provides an update on the advances in CBD research to date and the potential areas of future exploration.

BackgroundPhotoprotection of human skin is determined as the capacity of sunscreens to prevent ultraviolet (UV) B radiation‐induced erythema and UVA radiation‐induced pigmentation. It is unequivocal that, in addition to sunscreens, oral supplementation with carotenoids can protect human skin against UVB radiation‐induced erythema. It is not known if this is also the case for UVA radiation‐induced pigmentation.ObjectiveTo clinically evaluate the photoprotective effects of daily supplementation with carotenoids against UVA radiation‐induced pigmentation.MethodsIn this double‐blind, placebo‐controlled trial, 60 subjects (Fitzpatrick types II‐IV) were randomized to receive Nutrilite™ Multi Carotene supplement or placebo for 12 weeks. UVB‐induced minimal erythemal dose (MED), UVA‐induced minimal persistent pigmentation dose (MPPD) and skin carotenoid levels were measured at baseline, 4, 8, and 12 weeks of intervention. Skin color was evaluated by expert clinical graders and by colorimetry. Carotenoid levels in the skin were measured by the Biozoom® device.ResultsIn the intervention group, a significant increase in comparison with the placebo group was observed in (a) skin carotenoid levels, (b) UVB‐induced MED, and (c) UVA‐induced MPPD values obtained by colorimetry.ConclusionDaily supplementation with carotenoids protects human skin against both UVB‐induced erythema and UVA‐induced pigmentation.

Skin, the largest organ of the human body, is exposed daily to environmental aggressors such as solar radiation and air pollution, resulting in many acute and chronic conditions. [1][2][3] The damaging effects of UV radiation on skin include erythema (sunburn), pigmentation (tanning), photocarcinogenesis, and photoaging. [4][5][6][7] Other exposomal factors such as air pollution, 8-11 tobacco smoke, 12 infrared radiations (IRs), 13,14 ozone, 15 and alcohol consumption 16 also have detrimental effects on skin health. 17 From a mechanistic point of view, all these environmental threats seem to involve oxidative stress as one common denominator. Interestingly, most of the skin's solar exposure throughout the lifetime is incidental, under normal conditions when no sunscreens are used. 18 Preventative strategies such as the use of sun protective clothing, avoiding sun exposure, and the use of sunscreens are ideal for photoprotection. In the Western world, where sunbathing and tanning are popular, combined with the global lack of consumer awareness for adequate or frequent use of sunscreens, these strategies are often rendered ineffective.In the absence of any topical photoprotective intervention, skin's primary defense solely rests on endogenous protection.

Despite the notable health benefits of carotenoids for human health, the majority of human diets worldwide are repeatedly shown to be inadequate in intake of carotenoid‐rich fruits and vegetables, according to current health recommendations. To address this deficit, strategies designed to increase dietary intakes and subsequent plasma levels of carotenoids are warranted. When mixed carotenoids are delivered into the intestinal tract simultaneously, competition occurs for micelle formation and absorption, affecting carotenoid bioavailability. Previously, we tested the in vitro viability of a carotenoid mix designed to deliver individual carotenoids sequentially spaced from one another over the 6 hr transit time of the human upper gastrointestinal system. We hypothesized that temporally and spatially separating the individual carotenoids would reduce competition for micelle formation, improve uptake, and maximize efficacy. Here, we test this hypothesis in a double‐blind, repeated‐measure, cross‐over human study with 12 subjects by comparing the change of plasma carotenoid levels for 8 hr after oral doses of a sequentially spaced carotenoid mix, to a matched mix without sequential spacing. We find the carotenoid change from baseline, measured as area under the curve, is increased following consumption of the sequentially spaced mix compared to concomitant carotenoids delivery. These results demonstrate reduced interaction and regulation between the sequentially spaced carotenoids, suggesting improved bioavailability from a novel sequentially spaced carotenoid mix.

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