The bidirectional communication between the skin and brain has emerged as a promising scientific paradigm in the cosmetic industry. Indeed, the skin is not just a passive barrier; it contains a variety of neurotransmitter receptors and neuromediators. Moreover, it has been shown that psychological stress increases glucocorticoids (GCs) by activating the hypothalamic-pituitary-adrenal axis. Negative effects of GCs on the skin barrier is well-established (Choe et al., 2018), with stress and the gradual decline of hormones being key factors in skin aging in men.

Objectives

With an innovative psychobiological approach including in vitro and in vivo tests, the aim of this study was to evaluate the effect of an Aspalathin-rich Aspalathus extract (AE). Thanks to this systemic approach, evaluations were realized on a) the expression of aging and androgen-related genes in normal human epidermal keratinocytes b) skin neuromediator pathways linked to soothing and well-being using a co-culture model of keratinocytes and sensory neurons, and c) effects on mood and stress using validated psychological tests in men.

Results

AE targets aging-related genes by enhancing the endogenous intracellular levels of antioxidant capacity (SIRT3, HMOX1) and stimulating skin regeneration factors (TFAM, GDF11, SIRT4). AE also significantly stimulated the expression of gene encoding the androgen receptor (AR). Simultaneously, the extract increased the expression of steroid sulfatase (STS), an essential enzyme that regulates the conversion of the inactive precursor dehydroepiandrosterone sulfate (DHEA-S) to the active form DHEA and its downstream androgens. These mechanisms strongly suggest that the active ingredient influences the bioavailability of androgens within the skin. The results obtained on cortisol metabolism are also highly relevant, showing a regulatory effect that limits cortisol synthesis. Furthermore, the subjective perception of well-being evaluated through the Profiles of Mood States (POMS) and the STAI scales significantly improved in vivo.

Conclusion

The systemic approach used through specific in vitro and in vivo tests has shown AE acts as an agonist or antagonist on neurotransmitters (neuropeptides, neurohormones, neurotransmitters) or on the enzymes that synthesize them, offering a novel approach to anti-aging skincare aligned with the concept of the skin-brain-hormonal axis in men. Its efficacy has been confirmed by an in vivo study measuring improvements in markers of firmness, skin density, and reduced signs of stress-related fatigue in men. This study has shown the importance of the inclusion of psychobiological aspect in the study of anti-aging particularly in men