Making a positive impact: COSSMA

Since sensitive skin reacts very quickly to irritation, special attention must be paid to the choice of ingredients in formulations for this type. Dr Nora Schiemann and Anne-Sophie Gardes present a solution for achieving immediate effects with this skin type.

Most important is a frame formula providing a balanced blend of mild emollients and skin conditioning agents, which support the skin function and provide protection to the surface. In such a formula active ingredients can be added. A selection of highly effective ingredients which either do not irritate skin or a blend of ingredients which contains actives with skin soothing or anti-inflammatory effects is crucial.

Regarding anti-ageing claims, consumers can find products that meet both their need for immediate and long-term efficacy. When it comes to sensitive skin, it’s difficult to offer solutions providing immediate benefits.

Skin appearance of a study participant at the start, after four and after eight weeks. photos: IMCD

Emerging trend: solids

Solid product forms have been identified as offering clear advantages1. In addition, we should clearly consider to making a positive impact at all levels. Consumer perception drives this change. This is where  the concept of products with less water comes from.

Waterless claims have been increasing over years. More products are being launched and the increasing number of solid product forms versus the number of claims2 already gives a flavour as if products with less or no water become the new normal.

The selection and right association of active ingredients together with functional ones, is a key factor to boost the formulation performance.

Mintel recommends that brands think more broadly when entering the waterless category than just eliminating water from the product. The true impact will come from how that product is used by the consumer, and more importantly, what is left over after the product is used up. Performance is key.

Change rate score of the sagging angle (%) at the start and after four weeks. Test measurement device: Moire topography. illustration: IMCD

Concept for sensitive skin

Let’s introduce a particular formula whose composition of primarily natural ingredients is balanced in a way that the application is easy, and the solid product is melting at skin temperature and spreads easily.

In the ingredients list there are waxes, oils and elastomers of natural origin, an emulsifier which stabilises the composition of the lipids with different polarity in a W/O emulsion.

It is possible to add various colours and pigments, as well as functional actives and a broad variety of water and oil soluble actives. Due to its solid state the beads can effectively take loads of functional particles, which easily boost solid forms.

The formulation is in line with clean beauty concepts and ISO 16128 standard³.

The Cosmoscompliant Polyglyceryl-10 Heptahydroxystearate with HLB 5.94 is key to blend the different ingredients. A high load of Triheptanoin5 provides a light and non-greasy cream texture. Despite the concept appearing to be quite similar to the recently presented finger-beauty formula1. There are significant differences in ingredient selection and composition.

Also, the combination of two gelling waxes (sunflower wax double refined and cera alba) helps to thicken the formula and establish the desired texture. Sensory aspects of the formula are being adjusted by using a naturally derived elastomer gel6 that contains the natural elastomers in shea butter, which is more suitable to formulate high viscous products. To prevent the oil phase from oxidation, a very effective Cosmos organic compliant antioxidant⁷ has been introduced.

The optimised selection and combination of specific functional ingredients enables a significant water phase (about 34 %), so that water soluble actives can be included in addition to the oil soluble ones.

Depending on selection of actives and a special colour pigment, embedded in an oil dispersed elastomer gel8 which combines well with the oil phase, the formulation reaches a natural origin index of >0,99 according to ISO 16128.

Among the selected active ingredients, which have an anti-inflammatory effect together with anti-pollution properties, we recommend Shiso Extract and Dipotassium Glycyrrhizinate are recommended9, as well as Stearyl Glycyrrhetinate¹⁰.

A good add on in this context are ingredients which help establish a functional skin barrier, e.g., Hyaluronic Acid with very short chain length.

Both the blank placebo treatment as well as the retinyl palmitate treatment did not change the appearance of the skin significantly. Only for the group treated with a serum containing Granactive Retinoid, could significant improvement be observed. illustration: IMCD, graph: IMCD

Extra moisturiser

A hyaluronic acid, effective at low concentration11 with a very low molecular weight, can penetrate to lower layers of the skin and has been tested in vitro, by a human patch test and repeat insult patch test as non-irritant. Even at a very low concentration of 0.1% it improves skin texture and appearance over time.

In clinical studies, an increase in collagen production, skin moisture, as well as an improvement of skin texture could be substantiated. Also, the effective reduction of wrinkles (crow’s feet and nasolabial folds) by using a lotion containing 0.1% HA-Booster over a period of four to eight weeks could be proven. Even a reduction in sagging in the cheek area has been observed.

Besides these ingredients we should have a look to oil soluble actives, which are beneficial especially for sensitive skin.

After application on a 24-hour occlusive patch test, hydroxypinacolone retinoate demonstrated a significantly lower irritation profile versus retinol. Test samples were 0.5% retinoid in Gransolve DMI. illustration: IMCD, graph: IMCD

Vitamin A

Retinol, also known as Vitamin A, is a well-known ingredient in anti-ageing products. However, the irritation potential of retinol makes this ingredient unsuitable in products for sensitive skin.

Indeed, derivates of retinoic acid are less irritant compared to Retinol. Hydroxypinacolone retinoate¹² has been identified to provide the bene-fits of Vitamin A, but without skin irritation.

Moreover, exposed to sunlight, this retinoate has been evaluated as non-phototoxic. In clinical studies hydroxypinacolone retinoate has been proven to reduce effectively wrinkles, age spots, skin roughness, skin texture and UV-spots, even in a relatively short time.

In a clinical study with three groups, a retinoid serum had been applied twice per day, only one pump per application. Group A received the serum with 0.2% hydroxypinacolone retinoate¹² in DMI, group B only a blank placebo and group C a positive control containing retinyl palmitate at 0.2%, in DMI. Texture improved and UV Spots decreased over a period of twelve days.

Conclusion

A solid cream for sensitive skin is possible, for targeted and wide application. Formulators with special know-how overcame the technological challenge of designing a solid emulsion, whose water phase amount is about 34%.

Water phase is indeed essential to provide a melting and creamy skin feel when applied and to deliver water soluble active ingredients, both benefits answering the sensitive skin specific needs. Several possibilities exist to customise and enhance the functions of this frame formula, which is designed for sensitive skin.