INTRODUCTION
The cosmeceutical industry has produced countless new products to target signs of cutaneous aging, reduce acne, decrease hyperpigmentation, improve texture, and many other concerns. Peer-reviewed, clinical trials help inform the recommendations experts provide to their patients regarding these products. Multimodal skincare products are increasing in popularity. These contain many active ingredients targeting several mechanisms of clinical stigmata of cutaneous damage including fine lines, texture, and sallowness, acne formation, and notably, signs of aging.
Perhaps the most pervasive and well-known factor that contributes to clinical signs of extrinsic aging and degradation of cutaneous integrity is photodamage. Exposure of human skin to ultraviolet radiation induces DNA damage that triggers photoaging, cell death, and carcinogenesis.1 Thus, many skincare products are designed with these mechanisms in mind. The inclusion of light-responsive ingredients, adaptogens, probiotics, and specialized peptides in skincare have enhanced the ability of products to respond to both environmental cues such as the ultraviolet (UV) and visible light spectrum, as well as encompass intrinsic cues such as cortisol-driven stress response, circadian rhythm, and commensal flora.2–5 For example, extrinsic DNA damage induced by UV radiation is repaired by photolyase enzymes. Growing evidence shows that when applied to the skin, topical liposomal formulations of these enzymes can contribute to DNA repair to reduce signs of photoaging as well as carcinogenesis.6 Taking this a step further, some topical photolyase enzymes are activated by UV radiation, making them light-responsive. Therefore, photolyases are augmented by the environment that generates DNA damage and are photodynamic.7
Circadian physiology is perhaps the meeting point of extrinsic and intrinsic cues, considering the extrinsic light cycles that govern our intrinsic circadian clock. A growing body of evidence
Perhaps the most pervasive and well-known factor that contributes to clinical signs of extrinsic aging and degradation of cutaneous integrity is photodamage. Exposure of human skin to ultraviolet radiation induces DNA damage that triggers photoaging, cell death, and carcinogenesis.1 Thus, many skincare products are designed with these mechanisms in mind. The inclusion of light-responsive ingredients, adaptogens, probiotics, and specialized peptides in skincare have enhanced the ability of products to respond to both environmental cues such as the ultraviolet (UV) and visible light spectrum, as well as encompass intrinsic cues such as cortisol-driven stress response, circadian rhythm, and commensal flora.2–5 For example, extrinsic DNA damage induced by UV radiation is repaired by photolyase enzymes. Growing evidence shows that when applied to the skin, topical liposomal formulations of these enzymes can contribute to DNA repair to reduce signs of photoaging as well as carcinogenesis.6 Taking this a step further, some topical photolyase enzymes are activated by UV radiation, making them light-responsive. Therefore, photolyases are augmented by the environment that generates DNA damage and are photodynamic.7
Circadian physiology is perhaps the meeting point of extrinsic and intrinsic cues, considering the extrinsic light cycles that govern our intrinsic circadian clock. A growing body of evidence
