How Can You Preserve DIY Cosmetics?

Ejogo inquires…I’m working on a product for my hair which is thin and I find that using the egg with other products works but after a few weeks, it goes bad. What chemical can I use to keep it from going spoiled but doesn’t damage my hair? Any help is greatly appreciated.

The Right Brain responds:

As we’ve pointed out in previous posts on preservative free products,  you could be in for a world of hurt if you’re using unpreserved cosmetics. This is especially true for products based on eggs (nature’s perfect nutrient) because they provide such a good nutrient base for bacteria to thrive on. If you mix your own product and use it while it’s fresh you’re less likely to have any problems. But if you have any “left overs” you’ll need some plan to protect them from spoilage. Refrigerating the product helps for a few days but for long term storage you’ll need some kind of chemical preservative to ensure protection from contamination.  But that’s where it gets tricky – picking the right preservative and understanding how to use it is not always an easy thing.

Pick-a-preservative

If you chose the wrong preservative it may be uneffective against the kinds of microbes likely to contaminiate your product. Or, even if you chose the right one, there maybe some other ingredient in your formula that deactivates it.

Dose makes the poison

Dosage is the second issue. Even with the right preservative in the right system you have to chose the right dosage. For products made in a very clean kitchen that are stored in very clean glass jars, you can probably get by with a lower preservative load. But if you’re using any dirty utensils or mixing vessels that weren’t propertly santizied, you may be introducting bacteria that will overwhelm your a low level of preservative.

Mix master

Processing also has an impact on preservative efficacy. Some preservatives are destroyed by heat so if you’re mixing in your preservative to a batch that’s still hot you may render it ineffective. That’s why these ingredients are typically added to the batch last.

Testing is challenging

And after all that, there’s no sure way to know if you’ve properly preserved your product without testing. Cosmetic scientists do what is called a “challenge test” that involves spiking samples with a known number of microbes. The growth of these microbes are then tracked on agar plates to see how much the preservative system controlled. If the growth rate is too high, the product is not considered properly preserved. Since the average person lacks the ability to run such a test, you’re always incurring some degree of risk when you try to preserve your own cosmetics.

The Beauty Brains bottom line

It’s impossible for us to recommend a preservative for you without knowing exactly what’s in your formula. And even then, we would want to make sure the proper testing was done  to make sure the preservative system is safe and effective.  This isn’t a very helpful answer to your question, but we’d rather have you be safe than sorry!