Skin absorption is a route by which substances can enter the body/bloodstream through the skin. How many times have you read that the skin absorbs 60 % of what we apply to it? I was actually told this at college! This is one of the many skin myths that has been hyped by the media and also the Organic/natural companies as it supports their ideals that it is better to apply less chemicals to your skin! Unfortunatly for them, this simply isn’t true.
In general the primary function of the skin is to act as a barrier that prevents the invasion of external materials, especially the large molecules of skincare products. Cosmetic companies have to work very hard to develop formulations that can actually be absorbed through the epidermis to deliver all the claims that they make! and the line is frequently crossed of “is it a cosmetic or a drug?” a product cannot be too active for mainstream cosmetics, as they have the potential to irritate – this also depends on how resistant/sensitive your skin is, to how far ingredients can get. For example retinoids – the strongest forms are prescription only drugs, as they can affect the structure of the skin in a dramatic way.
Professors and academics whose sole job is to analyse skin permeability all admit to the fact that little can “slip” through the upper layers of the skin (epidermis). Most molecules in skincare products are far too large to even reach the Dermis, let alone pass into the bloodstream.
If we did absorb 60 % of what we apply to our skin, the human race would very likely not exist! not to mention absorbing all the water we bath in, and a sludge of creams and serums floating round our body! Our skin has to be highly effective at keeping body fluids in and microscopic bacteria out!
However there are ingredients that can penetrate the dermis, and some drug delivery systems are in the form of trans-dermal skin patches, nicotine patches deliver nicotine to the bloodstream, the synthetic sunscreen Octyl Salicylate has very small molecules and studies have shown continual application for 48 hours results in 1.58 % being absorbed – hardly 60 %.
For more information on specific ingredients visit The Research Institute for Fragrance Materials (RIFM), they generate, evaluate and distributes scientific data on the safety assessment of fragrance and raw materials in cosmetics, shampoos, creams and other personal & household products.
The Skin-Forum is also an organisation dedicated to studying skin permeability.