Stability Testing Cosmetics

See all those little handwritten labels all over those bottles up there? They're there so I don't forget which product, batch, date, contents, preservative, etc was used when I made them. Speaking from memory, I could only tell you which product and maybe the year.

We're going to talk about stability testing of our products today. I realise the subject isn't all that sexy, but it's part of making cosmetics.

And before we continue, I have a confession to make. My own stability testing has – for much of my cosmetics making life – been in real time.

You: Holy canoly Lise! You must have a lot of cupboard space!
Me: One prioritizes

What Needs Testing

Every cosmetic you make should be monitored and tested. I usually save a generous sized sample, but sometimes it's an entire bottle/jar/container that is labeled with date, contents and all other relevant info before being placed into the 'stock cupboard'.

Skin Tonics, Cleansers, Shampoos, Balms, Lotions, Creams, Serums and Hair products of every imaginable type have been subject to standing around for months, years and on one occasion, over a decade (it was a lip balm that had snuck behind some other products and hid on purpose).

If you make glycerites, macerations, infusions or extracts, it is highly recommende to save samples for monitoring and testing as well.

Remember These?

Check out these no-soap cleansers. If you've been following this blog for a while, you may even have made and tried them yourself. The one on the left is from 2015 and there's a how-to right here. The one on the right is from the same year and is mentioned right here.
They're still both behaving like champs. To be honest, it doesn't surprise me in the least. First: I've made this kind of product a zillion times, and second: I added preservatives to this anhydrous mix because I knew they would be living in the bathroom and have drippy wet fingers dipped into them on a regular basis.

Now before you get all discouraged about all the TIME it takes to test products, please don't worry.

You don't have to wait that long. Most people have better things to do than observe their own concoctions for years on end.

This post is mostly to give you a link to a fellow formulators Guide to Quick and Dirty Stability Testing so you can get your answers in under a decade.

Thanks for the link, Rebecca!

Happy Testing!

Do Tell

How do you stability test your products? Please share in a comment below

More Info

Also on this blog: How to tell if your product has gone bad