Holistic Solutions for a Refreshing Beauty

With Global warming being a reality, the temperatures will have a tendency to increase overtime, indeed according to the Intergovernmental Panel on Climate Change, global average temperatures are estimated to rise 1.5 degrees Celsius above preindustrial levels sometime around “the first half of the 2030s,”.

Consumers will feel warm and will be looking for solutions that provide freshness. Menthol or menthol derived products have always been ingredients that are well appreciated in beauty routines as they aim to deliver an instantly refreshed and energized feeling to skin. Therefore, we expect this market to keep growing in regions all around the world.

Neurosensory Process

Although widely used, the ability of menthol to activate the receptor sensitive to cold was discovered not so long ago1. This receptor is called TRPM8. This activation by physical stimuli (cold) or chemical stimuli (menthol and its derivatives, for example) generates an electrical message conveyed via sensory neurons to the brain and leads to the creation of a cooling sensation (Fig.1), it is therefore a neurosensory process. The TRPM8 receptor is an ion channel belonging to the family of TRP (transient receptor potential). Different TRP receptors(TRPV1-4, TRPM8, TRPA1) have been identified in the skin where they transmit the perception of temperature (thermal stimuli). The TRPM8 receptor is expressed on sensory neurons and is also expressed on non-neuronal epithelial cells. [caption id="attachment_157182" align="aligncenter"] Figure 1. Skin scheme showing how
freshness is sensed[/caption]

A Range of Solutions to Generate Freshness

Despite a very effective freshness sensation, the disadvantages of menthol are numerous. They include a strong smell or taste, a burning sensation (generally not tolerated by sensitive skin) and a high volatility. These undesirable properties limit its use to some extent in anti-aging formulations where tolerance and sensorial aspects (pleasant scent) are very important for consumers. Therefore, Symrise overcame these disadvantages by developing a range of cooling agents able to generate a cooling sensation on the skin, with the same physiological mechanism of action as menthol, but limiting the undesirable effects of the menthol. Frescolat® ML range (INCI: Menthyl lactate), is a menthol derivative (menthol ester) capable of generating a mild and gentle cooling sensation on the skin. Its use is now widespread in many applications (rinse-off and leave-on applications). Well tolerated and completely odorless in formulation, Frescolat® ML creates a freshness in perfect affinity with the skin. It has been recently shown in an in vitro test that this range was helping to protect against the growth of bad bacteria in the intimate area. This range is composed of a colourless to liquid (Frescolat®ML) and a powdery crystalline form (Frescolat® ML cryst new quality), as long as a natural one (Frescolat® ML nat), which is 100% natural and Ecocert certified. This range allows to answer to all formulation needs and sustainability requirements. A long-lasting sensation of freshness is also a key parameter for the consumers, Frescolat® X-cool (INCI: Menthyl Ethylamido Oxalate) provides an “icy effect” that can attract consumers looking for ever more sensory experience. On top of its high efficacy profile, this ingredient is also easy to process (viscous liquid product, colorless, odorless, no influence of color and odor on final formulation). Others cosmetic applications need ingredient suitable to high pH, Frescolat® MGA (INCI: Menthone Glycerin Acetal) is the solution to bring freshness to alkaline formulations such as depilatories and deodorants. It provides a long-lasting cooling effect and acts as a relief player in hair treatments. To get an even stronger freshness effect, a mixture of menthol diastereoisomers and menthyl lactate was developed as Frescolat® Plus (INCI: Menthol, Menthyl lactate). This ingredient generates a sensation like menthol but without the minty odor. The cooling effect of Frescolat® products was confirmed and quantified in an in vivo study using an expert panel of 12 subjects. The volunteers applied (sequentially) on the face several emulsions containing Frescolat®. For each emulsion tested, a time-intensity profile was obtained by evaluating the intensity of the perceived sensation of freshness on a scale from 0 (no cooling effect perceivable) to 10 (very pronounced cooling effect). Measurements were recorded every minute for 30 minutes (Fig.2). [caption id="attachment_157188" align="aligncenter"] Figure 2. In vivo study evaluating
freshness intensity[/caption] The sensory profiles have a characteristic shape (bell curve), indicating that the cooling sensation caused by the cooling agents, grows gradually during the first minutes following the application and then gradually fades in less than 30 minutes for all Frescolat® ingredients, where Frescolat® Plus showed the strongest and quickest intensity with a peak at 5 minutes. These timeintensity profiles also reveal that Frescolat® X-cool and Frescolat® MGA induce a very intense and long-lasting cooling effect. This self-perception of freshness sensation is also strongly associated with well-being. Cooling Down and Well-Being: Frescolat® ML Cooling down helps to regulate the perception of stressrelated heat and restores a sensation of comfort. Mintel predicts that the beauty industry will meet this new consumer need with mood-enhancing products that directly address emotional health and healing2. The latest studies of Frescolat® ML uses Neurosciences to demonstrate how the cooling sensation can induce positive emotions.Symrise developed in 2019 the Gen-isys program, a Neuroscience program which approach was to improve the validity of consumer research by integrating multiple ways of data collection across:

• Biometrics: measure of heartbeats that indicates a relaxation/ stimulation state of the body.
•  Neuroimaging: use of electrodes to monitor electrical activity (EEG) of the brain.
• Explicit survey: subjective method aiming to ask volunteers to consciously describe their feelings through questionnaires. These methods allow us to evaluate the subconscious and conscious emotions.

The study has been performed on 35 Malaysian women aged between 18 and 45 years old. Each volunteer tested two products an emulsion with 0.8% Frescolat® ML and placebo emulsion at similar times on separate days, as part of a rotation (half of the group used placebo first and half of the group used Frescolat® ML first). Product application lasted for a duration of 20 min and results were obtained by software acquisition (neuroimaging & biometric parameters) while questionnaires were filled in by volunteer and then analyzed statistically. The heartbeat was measured at the moment when the placebo or the Frescolat® ML emulsion was applied on the skin thanks to a captor attached to the panelist’s fingers. The results showed that the product containing Frescolat® ML showed a higher variation in heartbeat and though stimulation was enhanced thanks to the ingredient (Fig.3). [caption id="attachment_157190" align="aligncenter"] Figure 3. Heartbeat rate monitoring with 0.8% of Frescolat® ML[/caption]   [caption id="attachment_157192" align="aligncenter"] Figure 4. Heartbeat rate monitoring with 0.8% of Frescolat® ML[/caption] Then the product was evaluated with an electrophysiological method. The EEG electrodes (headset with several electrodes recording the brain activity) were put on the scalp of the panelist. The left frontal brain activity measures the positive emotions while the right one measured the negative ones. The sensors attached to the scalp are measuring the energy and recorded them as waves that all stand for different mood states. The relaxation is measured from the teta wave intensity towards the back of the head. The experiment results showed that the product containing the ingredient induced less relaxation to the panelist, which is related to the stimulation and though confirm the biometrics results. To finish, panelists evaluated via explicit survey the cooling sensation and intensity that they felt. These conscious evaluations showed that almost 97% of respondents described the formula with Frescolat® ML as cooling and graded it as more intense than placebo. These data have shown that the freshness sensation could induce a feeling of well-being, but the well-being is also related to the diminution of discomfort sensations.

Retinol Tolerance Enhancer: Frescolat® ML

The retinol comes from vitamin A, which is a nutrient that helps drive cell turnover and that increases collagen production and decreases collagen breakdown. This ingredient is largely used in anti-ageing products and is predicted to grow at a compound annual growth rate (CAGR) of 3.8% from 2023 to 2030(3). Despite its high efficacy, this ingredient is also known to give dryness, irritation, and stinging sensations to the skin. To offer the possibility to formulators to continue using this ingredient without its side effects, Symrise has launched an in vivo testing on 22 volunteers sensitive to retinol in order the evaluate if the discomfort sensations induced by retinol could be reduced with Frescolat® ML as a tolerance enhancer. ingredient They evaluated these unpleasant sensations (burning, stinging and warming) induced by retinol comparing a formula containing both retinol and 1% Frescolat® ML, and a control formula with retinol only. The results show that the formula containing the Frescolat® ML, significantly and instantly soothed the uncomfortable sensations induced by retinol. [caption id="attachment_157194" align="aligncenter"] Figure 5. Discomfort sensations of retinol reduced with 1% of Frescolat® ML[/caption]

Conclusion

Able to generate a cooling sensation on the skin, all Frescolat® ingredients help to recover a full sensation of thermal comfort. Available in various forms (liquid, solid…) and suitable for a wide range of pH, there is a Frescolat solution for any formulation need. This range of ingredients is the perfect tool to improve the well-being of consumers and provide freshness. References 1 McKemy et al., Identification of a cold receptor reveals a general role for TRP channels in thermosensation. Nature. 2002. 416 52-58 and Peier et al., A TRP channel that senses cold stimuli and menthol. Cell. 2002. 508:705-715 2 Mintel GNPD database: Beauty Spot: Beauty taps into the emotions, published in June 2018 3 Grand Review Report: Retinol Market Size, Share, Growth & Trends, 2023 Translation and Compilation Tuğba Bayazıt Senior Application Technologist Head of AMET Application Labs Symrise AG Author:Héloïse Bouchez Junior Global Product Manager Cosmetic Ingredients Division BU Actives & Botanicals Symrise S.A.S.