Lecithin may enhance skin absorption, which should be considered with caution when using leave-on products possibly containing other harmful ingredients. Other ingredients can easier penetrate and be absorbed through the skin. It is generally recommended to use this substance in rinse-off products, and at maximum 15 % in leave on products.
The other concern of this substance is that it may be contaminated by nitrosamines. Lecithin should be avoided in cosmetic products where N-nitroso compounds may be formed. It has been reported that lecithin metabolize to choline, and the choline can in turn be dealkylated to dimethylamine. It is dimethylamine that can form nitrosamines if it’s in the presence of nitrate.
Lecithin may be derived from animals. It is a substance that can be found in all living organisms, for example in blood, nerve tissue, milk, and eggs of animals. But it can also be vegan; sourced from soybeans and corn, or be synthetically made, according to the People for the Ethical Treatment of Animals (PETA).
And as with many substances – no matter how this ingredient is sourced, vegan or non-vegan, it is often named the same. To know if the product is free from animal biological parts, look for “vegetarian” or “vegan” stamps on the product or in the product description. In some cases you may even have to ask the manufacturer to know how the ingredient is sourced.
- Nitrosamines – linked to cancer, endocrine disruption, organ system toxicity, developmental toxicity and damaged fertility.