Gleams & Notions

A Solution for sensitive skin

By Harvey M. Fishman, Consultant | March 1, 2012

Rahn Cosmetics, a Swiss company whose products in the US are distributed by Kinetik Technologies, Hazlet, NJ, is promoting an ingredient for sensitive skin called Defensil (INCI name: octyldodecanol, echium plantagineum seed oil, helianthus annuus (sunflower) seed oil unsaponifiables, cardiospermum halicacabum flower/leaf/vine extract).

This anti-irritant is registered and accepted in Europe, the US and Japan. It is preservative free, but contains 0.05% tocopherol. Defensil has a two-year shelf life, but should be stored under nitrogen between 4 and 15°C, and protected from light.

It is an oily, olive green liquid with a characteristic odor, which is non-toxic, non-sensitizing, non-phototoxic, or non-mutagen, non-irritating (skin and eye) and is readily biodegradable.

The three active ingredients work together, according to the company. Cardiospermum is a climbing plant found in the tropics. It was so named because of a white heart-shaped mark on the seed. In pharmaceuticals, it is effective against itching and allergic skin inflammation due to the high amounts of phytosterols and triterpenes present. Echium oil is extracted from seeds by cold pressing. This oil is very rich in stearidonic acid, an essential omega-3 fatty acid that has anti-inflammatory properties. The high proportion of 7- to 12% gamma-linoleic acid helps protect the skin barrier, as unsaturated fatty acids regenerate the intercellular cement of the epidermis. The unsaponifiable elements of sunflower oil, which have high sterol content, have a soothing effect on skin. They also contain natural vitamin E and squalene, which are very important to the regeneration and care of the skin.

Among efficacy studies conducted was an in-vivo stinging test, which measures the skin’s sensitivity to lactic acid. It was found that if a person with highly sensitive skin uses a cream gel containing 5% Defensil for one month, his or her skin will become less sensitive to lactic acid.

Another in-vivo test done was a micro-circulation test in which the skin is warmed by means of infrared radiation activating the micro-circulation. Irritated and reddened skin is normalized quickly and effectively with Defensil.

Irritated skin, in addition to causing redness, also increases the transepidermal water loss. Defensil was compared to hydrocortisone and panthenol and 2% Defensil had an immediate calming effect and reduced redness steadily over a long period.

Because of these properties, Defensil (1 to 5%) is recommended for use in sensitive care products such as baby care, after-depilation and aftershave products, preshave, lip balm and after-sun products. It is not recommended for use in sunscreen products.

A suggested skin product for the body is as follows.

Cream Gel
Ingredients: %WT
Phase A  
Water 85.6
Glycerin 4.0
Acrylates/C 10-30, alkyl acrylate crosspolymer 0.4
Sodium hydroxide 10% 1.2
Phase B  
Cetearyl isononanoate 2.5
Phenoxyethanol, methylparaben,
ethylparaben, propylparaben,
Defensil 5.0
Perfume 0.1
Xanthan gum 0.2

Procedure: Add third ingredient to water and glycerin in tank by sprinkling in the powder and stir until completely wetted (about 15 min). Neutralize with sodium hydroxide to produce a gel. Mix B in separate container, then add xanthan gum. Add this to A and homogenize until homogenous. No heat is necessary in this procedure.


Harvey Fishman has a consulting firm in Wanaque, NJ, specializing in cosmetic formulations and new product ideas, offering tested finished products. He has more than 30 years of experience and has been director of research at Bonat, Nestlé LeMur and Turner Hall. He welcomes descriptive literature from suppliers and bench chemists and others in the field.