For sensitive Skin

Often, we hear that natural ingredients cannot achieve sensory profiles which are quite common in premium cosmetics. In particular, product feel, skin feel and well-being are linked to each other. There are several aspects that have an impact on the desired cosmetic result. In many cases perfume makes the difference.¹

Natural ingredients and skin feel 

However, when it comes to sensitive skin, perfume is not likely to be the reason for buying. Internet research reveals that products for sensitive skin are likely to be formulated with less or even without perfume.^{2, 3} 

It is a fact that perfumes may contain allergens, which are explicitly requested to be mentioned in the ingredients list according to the EU Cosmetics Regulation. Especially for people with sensitive skin, these ingredient listings are important. Additionally, product feel and skin feel are in focus. We find that excellent slipperiness, softness and comfortable skin feel are important, accompanied by low tackiness. Sometimes also a powdery skin feel is desired.

For consumers, having sensitive skin and looking for a product that meets their needs, product feel and skin feel seem to play a much more important role, as we learn frequently in consumer panels. Natural formulations are often considered to have disadvantages in product feel and skin feel. 

On the other hand, due to the emerging Natural Cosmetics Trend, the sensory profile needs to be achieved by natural ingredients. Different approaches define naturality, e.g., COSMOS Standard, NaTrue Standard, ISO 16128 and others. Although actually silicones can be the best options for sensitive skin care, at least, if we look to pharmaceutical topical applications³, we find a trend in natural cosmetics to avoid silicones completely.

Even knowing that sustainable silicones are certainly made of natural feedstock (sand and bio-Methanol) and well suited for ‘clean cosmetics’, there is a trend to prefer ‘natural cosmetics’, possibly with high naturality index⁴. In this context we focus on ingredient concepts for sensitive skin, of which our research revealed that they are considered by consumers as suitable for ‘natural cosmetics’.

Ingredient Concepts for Sensitive Skin

Some ingredients are quite common when it comes to the development of a skin care formula for sensitive skin. An internet search will show a lot of different ingredients very often referred to as suitable for sensitive skin, e.g., Batyl Alcohol, Behenyl Alcohol and Lecithin, which are also called biomimetic materials.

All of these ingredients have been evaluated by the Cosmetic Ingredient Review (CIR) and considered as safe for use in cosmetics. Lecithin has been evaluated up to 50% with little irritation at this high concentration5, Behenyl Alcohol up to 50% with no irritation6 and Batyl Alcohol up to 3%⁷.

Batyl Alcohol on its own, provides strong anti-inflammatory properties and can then improve the final efficacy of the formula⁸.

Formulation Concept for Sensitive Skin

Besides suitable active ingredients the emulsifier is one of the most important components of a formula. For the purpose of developing a stable formulation which is suitable for sensitive skin, a combination of Batyl Alcohol and Lecithin together with Behenyl Alcohol have been used at the IMCD Skin Care and Sun Care Center of Excellence in Paris⁹.

In this formula a complex emulsifier, which contains Batyl Alcohol, Lecithin, Stearic Acid, Caprylic/Capric Triglyceride and Tocopherol has been used. This emulsifier can be obtained from Nikko Chemicals under the trade name NIKKOL Nikkolipid 81S¹⁰. Among other ingredients, Behenyl Alcohol has been used, which can be purchased also from Nikko Chemicals under trade name NIKKOL Behenyl Alcohol 80¹¹.

Procedure:

1. Mix phase A and heat to 80°C
2. Prepare phase B and add it to A
3. Mix phase C and heat to 80°C
4. Add phase C to phase A+B and homogenise by strong stirring (1500rpm) over 10 minutes, while maintaining temperature
5. Cool down at room temperature and add phase D and E separately.

The sensitive skin properties of the formula are provided by NIKKOL Nikkolipid 81S which also improves skin condition and the skin barrier function¹². 

Further studies on this material reveal different properties, which make this ingredient even more interesting for the formulation of sensitive skin care products¹⁰:

• Moisturisation
• Anti-inflammatory effect due to the presence of Batyl Alcohol in its composition.
• Water repellency

Beside NIKKOL Nikkolipid 81S the formula might contain other active ingredients, which enhance its efficacy. Recommended are the water-soluble Shiso Extract¹³ and Dipotassium Glycyrrhizinate¹⁴, which enhance anti-inflammatories effects. To improve anti-ageing effects even more, Zinc Glycinate¹⁵ can be added. Also, Dextrin¹⁶ as a multi-functional active ingredient, which is also microbiome friendly, can be blended in.

Instead of a perfume, an oil soluble plant extract might be added, e.g., Damascus Rose Extract¹⁷ or Lavender Extract¹⁸ in Squalane, which have been proven to be effective in Aromatherapy. Other oil soluble actives comprise Fullerenes, Vitamins and Vitamin Derivates¹⁹.

Also important for a sensitive skin cream is the sensory profile. In a consumer panel with trained panelists, the cream described above has been evaluated as having a product feel and skin feel which are comparable to premium skin care creams, including creams containing silicones.

Due to water repellency provided by NIKKOL Nikkolipid 81S the effects of the cream are more long lasting. To increase powdery feel, powders or elastomers can be added, also to enhance slipperiness and comfort. Elastomer gels like Gransense TC 18/XC²⁰ and/or Granpowder BBP-700²¹, both from Grant Inc. are powerful boosters in this context, as well as Sunsphere Silica particles from Asahi Glass Company²².

Conclusion

Sensitive Skin Care Cosmetics can be made with a great sensory profile, also respecting consumer demands, like perfume-free.

Batyl Alcohol and Lecithin together with Behenyl Alcohol are a good start to develop a stable and well-performing cream. The compound of Batyl Alcohol, Lecithin and Texturizers/Emollients provides multifunctional effects, which enable to achieve the most important aspects of Sensitive Skin Care.

References:

1. Joachim Mensing: Beautiful scent: The Magical Effect of Perfume on Well-Being, 1st ed. 2023
2. Google search: Sensitive Skin Care
3. Mintel DB search: Sensitive Skin
4. https://www.iso.org/obp/ui/
5. #iso:std:iso:16128:-2:ed-1:v1:enCIR Expert Panel Meeting, March 16-17, 2015, Report April 7, Safety Assessment of Lecithin and other Phosphoglycerides as Used in Cosmetics
6. Mary Ann Liebert, Inc., Publishers: Final Report on the Safety Assessment of Cetearyl Alcohol, Cetyl Alcohol, lsostearyl Alcohol, Myristyl Alcohol, and Behenyl Alcohol, Journal of the American College of Toxicology, Volume 7, Number 3
7. CIR Expert Panel Meeting, March 5-6, 2012, Alkyl Esters Re-Review – Supplemental Book 3, Relevant Alcohols - Batyl Alcohol
8. Sorav Das, Naohisa Yoshimi, Shuhei Tanaka:  US Patent US20150305994A1  https://patents.google.com/patent/US20150305994A1/en
9. IMCD Formulatory (available on request)
10. Product Presentation NIKKOL NIKKOLIPID 81S from NIKKO CHEMICALS
11. Product Presentation NIKKOL BEHENYL ALCOHOL 80 from NIKKO CHEMICALS
12. Nora Schiemann, Carmen Gutierrez, Anne-Sophie Gardes: Natural Boosting Power, COSSMA 3/2021; p. 16
13. Product Presentation SHISO EXTRACT POWDER CS from NIKKO CHEMICALS
14. Product Presentation DIPOTASSIUM GLYCCYRHIZINATE from MARUZEN PHARMACEUTICAL
15. Product Presentation NIKKOL ZINC-GLYZINE COMPLEX from NIKKO CHEMICALS
16. Product Presentation BEAUTÉ BY ROQUETTE DE 006 from ROQUETTE BEAUTÉ
17. Product Presentation BJ AROMASQUALANE ROSE from NIKKO CHEMICALS
18. Product Presentation BJ AROMASQUALANE LAVENDER from NIKKO CHEMICALS
19. Nora Schiemann, Anne-Sophie Gardes: Making a Positive Impact, Solid Formulation, COSSMA 4/2022; p.12 f.
20. Product Presentation GRANSENSE from GRANT INC.
21. Product Presentation GRANPOWDER BBP-700 from GRANT INC.
22. Product Presentation AGC SUNSPHERES from AGC