Author: melanie.castellanos@sfcosmeto.fr

Maximising skin performances throughout the day

Night repair mechanisms and metabolic strategies to mimic UV benefits during the day

By Anaïs BONNEFOY

Global well-being is closely linked to the performance of our biological functions, orchestrated by the circadian clock. This internal clock, synchronised with cycles of light, darkness, and even temperature, regulates many physiological processes that directly impact skin health. Although its main control centre lies in the brain, secondary clocks are present in almost every cell of the body. These are synchronised with natural light cycles through photic signals captured by the retina. The signals are then transmitted to the cells via electrical impulses, regulated by central genes such as CLOCK, BMAL1 and PER [1] [2], and relayed to secondary clocks by neural and hormonal mediators [3]. Many aspects of the skin thus follow a cyclic rhythm, including hydration, transepidermal water loss, capillary blood flow, sebum production, temperature, surface pH, and the proliferation rate of keratinocytes [4]. With the constant cellular renewal of the epidermis, the accurate synchronisation of these events is essential [5], though often disrupted by modern lifestyles.

Evaluate the performance of cosmetic formulations

State of the art and innovations in stability testing and sensory analysis

By Anaïs Bonnefoy, with the expertise of Anne Charpentier

The year 2024, marked by the Olympic Games in France, offers a great occasion to explore the performance of cosmetic formulations. Stability testing and sensory analysis are essential elements in evaluating performance. They play a key role in ensuring product stability over time, consumer safety, and the overall holistic experience. This article reviews stability testing and sensory analysis, highlighting the latest advances in these fields. To shed light on these aspects, Anne Charpentier, founder and director of Skinobs.com, the very first platform dedicated to referencing in vivo cosmetic efficacy testing, instrumentation, methods, and laboratories, shares her expertise.

Symposium 2023 “A Meta View on the Skin”

Review

By Anaïs BONNEFOY

During the “A Meta View on the Skin” Symposium, the exploration of the skin–brain axis highlighted key cellular interactions involved in a holistic approach to beauty. Then, the dive into the holobiont revealed its strong inspirational potential for active ingredients, although many aspects still remain to be explored. The objective of this Symposium was to provide a comprehensive and up-to-date vision of the essential role of the skin in global well-being, while also opening philosophical reflections.

A Meta View on the Skin: What are the components of skin communication?

Focus on intra- and extracellular vesicles, and different skin cells

By Anaïs BONNEFOY

In the previous articles, we reviewed the interconnections of the skin. We began by exploring its interface with the external environment, then examined its links with the human body, and finally discovered communication within the cells themselves. Connections between the skin and its external environment, as well as with other components of the human body such as the brain and the skin microbiota, are made possible thanks to coordinated communication between skin cells. This final part of the “Meta View on the Skin” series examines the mechanisms of intercellular communication within the skin.

A Meta View on the Skin: Interactions between skin and human body ecosystems

Skin–brain axis, skin–microbiome interconnections

Par Anaïs BONNEFOY

In recent years, two highly dynamic research fields have emerged, highlighting the essential role of the skin within a complex network of interactions with other physiological systems. On the one hand, work on the skin–brain axis has improved understanding of the skin’s neural mechanisms and how they can be modulated. On the other hand, research on the skin microbiome has deepened knowledge of the microbial ecosystem living on the skin surface and its role in maintaining cutaneous homeostasis.

The first part of this article describes the mechanisms linking the skin and the brain. The second part focuses on interactions between the skin and the microbiome.

A Meta View on the Skin: A dynamic interface connected with its environment

Review of the main external factors influencing immune processes and cutaneous homeostasis

By Anaïs BONNEFOY

Skin condition is often perceived as a tangible testimony of the passage of time, but it also reflects the environments in which an individual has evolved. It is therefore not uncommon, especially among informed observers, to rely on imagination to sketch stereotypical assumptions about a person’s past experiences. For instance, the presence of numerous age-related pigmentation spots, known as lentigines, may suggest prolonged sun exposure over many summers (and without adequate protection…). Conversely, a “baby-like” skin appearance at an advanced age may imply a healthy lifestyle (and possibly a favourable genetic background…).

Authorisation of new UV filters in Europe

A path paved with (regulatory) obstacles

By Marie Dehlinger

At the heart of numerous controversies throughout the summer, UV filters are cosmetic ingredients that are particularly challenged. So much so that the need to develop new molecules is on everyone’s mind. However, developing a new UV filter is already a complex process, to which must be added the regulatory steps required to authorise its future use in Europe. UV filters are not cosmetic ingredients like any others: their use in cosmetic formulations is governed by a very specific regulatory framework. Before protecting consumers from the sun, they must successfully pass all the steps required to demonstrate their safety of use, and also show a clean environmental profile from an ecotoxicological point of view.

Sun care products: controversial ingredients

Environment, health, efficacy, sensory aspects, regulation

By Anaïs BONNEFOY

Sun care formulation is one of the most challenging segments of the cosmetics market but also one of the most controversial.

The objective is to ensure complete protection against UVA and UVB, while providing a stable formula, pleasant sensory properties, safeguarding consumer health, minimising environmental impact, and keeping costs under control. On top of this, new developments are becoming increasingly innovative: waterless formats, sticks, sweat-resistant formulas, products for hair, and more… a real nightmare for formulators! What choices do they have today?