Preservative free cosmetic formulating - How to make them
There was an interesting question posed on the cosmetic science forum the other day. The forum member wanted to know whether they could still call a cosmetic “preservative free” if one of the raw materials was known to have a preservative (methylparaben) in it. That lead to a discussion about what a preservative free cosmetic is and isn’t.
Can you claim preservative free?
The answer to the first question depends on the ethics of your company. The cosmetic industry guidelines allow for you to not list processing aids so technically, you may be able to get away with claiming preservative free. However, this certainly breaks the spirit of the law as the claim is misleading and could quite possibly be illegal under FTC guidelines. I’m not certain how things would be different in places outside the US.
What are preservative free cosmetics
Forum expert Duncan added the following comments which is helpful for any cosmetic formulator looking to create a preservative free formulation. (Note comments have been edited slightly).
Preservative free formulations will include:
1. Waterless products:oil based
That would include things like baby oil, massage oil, or wax based things like lip balm. They don’t need preservatives because harmful microbes will not grow in them. Spores might land and rest on the product surface, but they won’t germinate.
2. Waterless products: Non oil based.
If your formulation uses something like glycerin or other glycols, these will not need preservatives. They also heat up when exposed to water which is why they are used for self heating formulations.
3. Water containing products that are preserved by a non preservative.
This would include cosmetic formulas that have a high level of alcohol as the alcohol kills the microbes. You might also consider formulations with high levels of sugar to preserve it like Jam, or high levels of salt. Reducing the water activity will reduce the ability of microbes to grow and thus be self-preserving.
4. pH controlled formulas.
Having a pH of 10-11 will discourage bugs, as will a very acidic pH. Only really ok for hand washing type products, or kitchen cleaners.
5. Using non-preservative preservatives.
The cosmetic raw material suppliers continue to research and have launched some materials that are not technically preservatives but they have a preservative effect. These products are in no way good enough to get registered as preservatives, but have some antimicrobial effects.
For example, Sensiva SC50. It is sold as a skin feel additive, with some limited antimicrobial activity. Used as a skin feel additive it allows you to reduce preservative levels. A bit of a grey area when some people use a lot of it to “Preserve” products.
6. Air tight packaged products.
Finally, you could technically make a standard water-based formula under aseptic conditions then package it into an air tight container (like an aerosol can). This should stay suitably preserved through the lifetime of the product.
Preservative free challenge
Preservative free products are very difficult to create because your options are limited. I personally don’t think it’s a compelling reason to buy a formulation and that your time would be better spent working on new benefits for your products, however, a number of consumers and your marketing group might disagree. Good luck!
