Neurocosmetics – innovative skincare pathways

Skin is the largest organ of the human body and it reflects the body’s inner workings and health as well as our emotions and age. On the one hand, it offers protection from harmful environmental factors and, on the other hand, it allows important substances into our cells while excreting the unwanted ones. Additionally, this fascinating and complex organ plays the role of a huge sensor that connects the brain with the outside world.  

The brain and skin share the same embryonic origin as the ectoblast, the outer layer of embryonic cells that gives rise to both the nervous system and the epidermis.

Our mental health directly influences the health and condition of our skin while, conversely, we can achieve a positive influence on our mental and emotional states through the topical application of cosmetics. Skin is a kind of an extension of the brain, and the two-way communication between these two organs opens new pathways and possibilities in skincare. 

The nervous system of the skin

Skin has three basic layers: the outermost is the epidermis, and beneath this we find the dermis and subcutaneous tissue. The outer layers of the skin, with the exception of the stratum corneum (corneal layer of the epidermis), are characterized by the highest nerve fiber density. There are two types of nerve fibers: sensory and motor.    

When nerve endings, sensory receptors, in the skin are stimulated we feel touch. These sensory receptors are sensitive to pain, heat, and cold. Meanwhile motor fibers carry impulses to blood vessels and hair erector (arrector pili) muscles that are attached to hair follicles. Stimulating the vascular nerves can either increase or decrease capillary blood flow. When hair erector muscles contract, hairs and follicles are dragged upwards, resulting in what we know as goosebumps.  

Skin, as a system for monitoring environmental factors (temperature, humidity, etc.) and perception (such as touch), generates impulses that are sent – via mediators – to the nervous system. Examples of mediators are neurotransmitters, which are chemical substances naturally synthesized by nerve endings but also produced by skin cells (keratinocytes, melanocytes, fibroblasts, and the like) and the immune system. The release of neuromediators can be triggered by physical, chemical, and even emotional stimuli. Among 200 neuromediators currently known to us, about 25 are found in the skin, such as neuropeptides.  

What are neurocosmetics 

Neurocosmetics influence the endings of sensory nerves in the skin, those that are sensitive to heat, cold, pain, itching, and pressure. These receptors send impulses to the central nervous system. Neurocosmetics do not influence our entire nervous system because they only work locally, where they have been applied.    

The first definition of such products has been attributed to professor Laurent Misery from the University of Brest (France), who in 2000 described neurocosmetics as “not absorbed products applied on the skin, exhibiting activity on the cutaneous nervous system or in general effects on the skin mediators”. 

The discussion about this new category of cosmetic products called neurocosmetics was also taken up in 2007 during the meeting of the New York Society of Cosmetic Chemists (NYSCC). As a result, a new group of cosmetic products was established: products that have the ability to cause reactions of the central nervous system in response to a local effect of a cosmetic product.   

Active ingredients in neurocosmetics

Neurocosmetic ingredients can use the following mechanisms of action: 

• Direct interaction with skin nerve endings as modulators of the release of neurotransmitters. Among examples we can list botulinum-like peptides that promote facial musculature relaxation in order to smooth out wrinkles, and peptides that inhibit neurons, mostly to lower the reactivity of oversensitive skin to environmental factors (changes in temperature, air humidity, smog, etc.). 
• Modulation of cellular functions as agonists/antagonists of neuropeptide receptors or as neurotransmitter modulators.

Based on the characteristics of nerve endings in the skin, researchers started looking for active ingredients that exhibit activity on those nerve endings.