Study made in collaboration with Services of Laboratory of Chemistry and Bacteriology of City of Gent, department of Belgium Ministry of Health.
COMPARISON STUDY BETWEEN DIFFERENT OILS ON BEHALF THEIR PENETRATION POWER INTO HUMAN SKIN
For each experimented oil the scale results give the average necessary time for penetrating into the human skin and also their type typical digressions.
Out of the gathered results, we now can draw several conclusions. The studied oils can be grouped in 3 categories according to their penetration through the skin.
- Those with highest penetration power. ( in digressive line) European Sesbellot™ Mink Oil – Linseed Oil – Cartharme Oil – Avocado Oil
- Those with medium penetration power; Walnut Oil – Tuna Oil – Rye Germs Oil – Wheatgerm Oil – Carob Germs Oil – Maize Oil – Codliver Oil – Soya Oil – Sweet Almond Oil – Hazelnuts Oil.
- Those with low penetration power Olive Oil – Colzaseed Oil-Rice Germs Oil.
[SCALE IN DEGRESSIVE LINE]
|Type of Oil||Average penetration time||Typical Digressions|
|Mink Oil||19.0||2.5 mm|
|Line seed Oil||20.0||2.4 mm|
|Cathame Oil||21.0||1 mm|
|Avocado pear Oil||23.0||3.4 mm|
|Walnut Oil||26.7||2.2 mm|
|Rye germs Oil||28.5||2.3 mm|
|Tuna fish Oil||28.5||4.5 mm|
|Carob germ Oil||29.0||4.8 mm|
|Maize germ Oil||32.0||4.8 mm|
|Codliver Oil||33.6||4.5 mm|
|Hazelnut Oil||39.0||1 mm|
|Soya beans Oil-normal||41.6||1.8 mm|
|Sweet Almonds Oil||44.0||5 mm|
|Wheat Germ Oil-normal||48.0||5 mm|
|Olive Oil||54.0||4 mm|
|Rice Germ Oil||70 mm|
|Colzaseed Oil||80 mm|
4. The Pharmacist naturally will tend to interpret these biological activity differences according to chemical or physical characteristic differences that mainly are.
A. Viscosity B. Iodine Incidence (non saturated fatty acids) C. % of unsaponifiable material D. % of lecithin E. Length of carbon chain of constituent fatty acids.
The negative influence of liquid viscosity on penetration power through the skin has since long has been noted by many authors. : Brown & Scott 1934-Valette, Cavier & Savelle 1954- Hadgraft 1961.
In fact, some of our results meet their assertions: it is according to their very low viscosity that MINK OIL, Linseed Oil Carthame Oil are showing their penetration power, It is according to their heavy viscosity that Rice germs Oil and Celzaseed Oil have a very poor penetration power. Between these two extremes, we can establish a satisfying correlative between speed of penetration power and viscosity. Exceptions to these rules are.
-Soya Oil: low viscosity but still slow penetration -Avocado Oil: Higher viscosity but strong penetration
These divergences will be explained because of action of other factors influencing the penetration speed into the skin (see below)
2. IODINE INCIDENCE
It is well known that the degree of unsaturated fatty acids influences the viscosity of oil and consequently the viscosity of their glycerides. But other structural elements and particularly the length of carbon chain of fatty acids provide the modifications of the physical characteristics. So it isn’t without interest, after having studied the influence of the viscosity of oils on behalf of their skin penetration power, to consider also the incidence of Iodine on the presaid penetration power.
1. Those with Weak Iodine value between 80 and 100 2. Those with Medium Iodine value between 110 and 125 3. Those with High Iodine value between 125 and 170
Very surprisingly, we find in this last category, oils with relatively high penetration power are for instance, Linseed Oil and Carthame Oil. There where in the category of weak Iodine value we find oils with medium or little penetration power as Olive Oil – Almond Oil- Hazelnuts Oils. Exceptions are shown by Mink Oil and Avocado Pear Oil both of weak Iodine Value and although having a high skin penetration power. We will see further what explanation can be given to these discoveries.
3. UNSAPONIFIABLE INCIDENCE
A high level of unsaponifiable materials shows to be non favorable on behalf skin penetration power of oils. This is anyhow the deduction which can be made by the examination of particular cases such as Carthame and Linseed Oil where the non saponifiable level lays under 1% there where the Rice germs oil (skin almost non penetrating) shows 11% and where the Rye germs oil of medium penetration power shows 8%.
4. LECITHINE INCIDENCE
A similar to the previous can be made showing the unfavorable incidence of Lecithine on behalf of the skin penetration power of oils.
Higher did we remain the exceptional character of Soya Oil, which although of light viscosity still shows a weak skin penetration power. But if now this oil is altered by eliminating time drops from 41.6 to 23.7. Similar results were obtained with Wheat Germ Oil (see scale)
5. LENGTH OF CARBON CHAIN
The gas phase chromatography of the ethyl esters of different oils studied, allowed to precise the composition of fatty acids and to study of relations between their chemical constituents and their chemical activity. Olive, Almond, and Hazelnut Oil all 3 are showing comparable physio-chemical characteristics, each with rather low skin penetration power.
Although there is only weak differences between them, still the skin penetration power shows differences: Olive Oil is best, followed by Almond oil and Hazelnuts oil. Here are the penetration power is regulated by the palmitic acid content. Decreasing percent of palmitic acid content shows and explains the decrease of skin penetration of these oils.
Linseed oil is, as said higher characterized by its high Iodine value and it is owing to this characteristic that this oil has a high skin penetration power.
Avocado pear Oil does not show any particularity by chromatographic research that can explain its relatively high penetration power. Traces of unidentified fatty acids, probably ethyl esters, are found. These acids of short Carbon chain is partly confirmed by the high acidity of this oil.
Mink Oil reveals a very special compound:
It is definitely an exceptional and unique blend of unsaturated fatty acids which makes Mink Oil a very active cosmetic ingredient. The C16 unsaturated fatty acid is not found in other commonly used cosmetic ingredients. Also 5.8% Myristic Acid, Linoleic and Palmitic Acid, Stearic Acid, Oleic Acid, Linoleic Acid, and Palmitoleic Acid. This variety of very exception acids gives to MINK OIL its high penetration power into skin, and makes it one of the best cosmetological ingredients for the skin care.