why the heck did I buy this and what can I do with it Wednesday post, Melody writes: Back before I found your blog and I was enticed by the idea of "natural" preservatives, I bought 2 fluid ounces of Grapefruit (Citrus Grandis) Seed Extract. Now that I know better, I'd never dream of using it as a preservative and it's been sitting in my supply cabinet gathering dust. I know it's an antioxidant, but I'm still wondering what the heck to do with it and I'd love to see if you can find a useful way to include GSE in a product. :)
I'm glad word is getting out about grapefruit seed extract not being a preservative, although I'm upset to see the supplier to whom you linked advertising it as such, talking about lab results they haven't posted.
Grapefruit seed extract is a water soluble anti-oxidant, so you can use it in your water containing products that way. The suggested usage is 0.05% to 2%, but I'd keep it under 1% until you see how you like it, what scent it adds to your product, and how it works with your skin type.
Add it to your lotions, shampoos, conditioners, and so on as an anti-oxidant. Also, use it as an astringent ingredient in something like a shampoo for oily hair. Treat it like you would an essential oil, which is to say you don't want to go adding it at huge levels, but consider it at up to 1% where you might want a grapefruit-y smell with some anti-oxidant properties.
So let's say you want to make a toner with some astringent and anti-oxidizing properties, add it at up to 1% in the cool down phase to add a little bit of oomph to that oily skin product. Consider using it the same way in a cleanser. And definitely try it in the oily hair shampoo. I'm not saying it's only for oily skin or hair, but astringent ingredients tend to be used for that type.
But please don't use it as a preservative as it doesn't work that way! (Check out this post to see the studies upon which I've based my statements.)
Preservatives: Choosing a preservative
A more in depth look at anti-oxidants
Why grapefruit seed extract (GSE) isn't a preservative (but is an anti-oxidant)
How do anti-oxidants affect the shelf life of your product?
Rancidity: A primer
If some essential oils are anti-microbial, why can't we use them as preservatives?