John Found Dip. Chem., C. Chem., MRACI, MAICD
Advertising around personal care and cosmetic ingredients seemingly knows no bounds. Any attention-getting claim or statement is perceived to be of high value in today’s internet driven world. Claims of “no nasties”, “safe”, “non toxic” and “all natural” are everyday occurrences designed to appeal to our sense of safety and well-being.
But how safe are natural ingredients?
Natural materials are not always safe as it turns out, some of the most toxic things known to man happen in nature. Botulinus toxin, produced by tiny bacteria for example, has lethal dose of about 1 nanogram per kg of body weight. The most toxic man-made chemical is the radioactive metal plutonium, which is arguably less toxic than botulinus.
A huge number of plants contain substances called alkaloids which are almost invariably toxic in miniscule doses. Ricinine, derived from the innocent sounding castor oil, was used by the Russians during the cold war to kill foreign agents. Strychnine, which is extracted from an equally evil sounding plant called nux vomica, is known to most as an infamous method of murder. The animal kingdom can be just as deadly with some super low dose proteins capable of causing paralysis and death. In general, natural ingredients are no more toxic nor safe than the equivalent synthetic chemical.
Isn’t it just a case of replacing the “nasty” chemicals?
The issue around natural ingredients is that they are complex in their makeup. Simple things like essential oils may have up to 120 different chemical isolates with many and varied properties. Formulating with pure chemical entities is much more predictable and offers much in terms of stability. In addition, natural ingredients often contain unwanted by-products that adversely affect things like odour and colour. The challenge for modern formulators is not so much being creative as it is trying to cover or remove objectionable properties from organic ingredients.
What are the challenges with natural ingredients?
The irony of using natural ingredients is that they are generally much more susceptible to spoilage and need robust treatment with chemicals to ensure finished goods offer good stability. Extracted oils, fats and waxes need purification and/or bleaching to make them useful as ingredients. Natural products also have a general tendency to “age” faster than their chemical counterparts due to oxidation. There is often a requirement to add chemical anti-oxidants to slow down the ageing process.
Because of their origins untreated raw materials often have very high a bio-burden which require high levels of preservation. Pre-treatment such as high temperature or fumigation with ethylene oxide to reduce bacterial and fungal load often result in damage and a reduction of efficacy.