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A few notes form my collage course
One of the first questions is how much of a chemical is absorbed across the skin into the bloodstream, and the rate at which it occurs.
Before a chemical can cause a toxic response in the skin, or indeed anywhere else in the body, it must first penetrate the skin's major barrier and the outermost layer. This horny layer is the stratum corneum which is made up of tightly packed, dead skin cells (keratinocytes). Absorption may also occur through hair follicles and sweat ducts.
The chemical must then enter the living epidermis (which consists mainly of keratinocytes in various stages of development) and it is here that toxicity may start, as the skin responds adversely leading to dermatitis, acne or cancer. If it reaches the upper dermis - which consists of a dense matrix of connective tissue, fibroblasts, macrophages, mast cells, lymphocytes, hair follicles, sweat glands, sebaceous glands, nerves, blood vessels and lymphatics - the chemical enters the general circulation to be carried to distant sites.
The skin has ways of protecting itself, such as the stratum corneum, sweating, enzymes and certain immune mechanisms, although most chemicals which are applied to skin are absorbed to some degree.
Aromatherapy has become very popular, with natural essential oils applied to the skin to relieve tension and to treat conditions ranging from skin disorders to cancer. Much is made of aromatherapy products being natural and therefore 'pure' and 'safe'. But this is not necessarily the case. Many natural essential oils are potent, concentrated chemicals. For instance, the oil from the pennyroyal plant contains 80 per cent pulegone which is a liver toxin. The essential oil derived from basil may contain over 80 per cent estragole which causes cancer in animals. Safrole is a carcinogen and is found at high levels in sassafras oil, while cinnamon bark oil can cause allergic skin reactions. And an important part of aromatherapy is massage, which increases the blood flow to the area. This, together with the application of essential oils to large areas of skin, may enhance skin absorption.
Using fresh human skin, we found that up to 33 per cent of MDA and 6 per cent of MbOCA could permeate the skin. Skin absorption, however, can vary considerably from one person to the next. Part of our study compared absorption of a variety of chemicals in humans with that in animals. In general, we found absorption is usually higher through animal skin. For the aromatic amines, however, the reverse is true. For example, 13 per cent of MDA permeated the skin in rats compared with 33 per cent in human skin, while for MbOCA the figures were 2 and 6 per cent respectively. This highlights the hazards of relying on animal experiments to predict the absorption of potentially toxic chemicals in humans.
I now the above is very long winded but :
Remember not to use salt scrub if you just shaved your legs or have minor cuts in your skin. If you’re pregnant or have medical problems, consult your doctor first before using any essential oils check with your doctor, especially if you have health conditions such as heart disease, ....
David
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The Isles of Ambar Cosmetics BY The Wikked Soaping Company Wokingham England
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