A few weeks ago I made a batch of lotions to try out the "natural" preservatives along with the olive-based emulsifier. I do think with further trials and adjusting the formula it could all be made to work fine. This would involve quite a bit more studying, money, and time, and so in the end I will not be pursuing lotions.
I had split one batch into two, adding Synercide Asian Fusion to one half (Water, Caprylyl Glycol, Hexylene Glycol, Wasabi Root Extract, Ginger Root Extract, Garlic Bulb Extract), and Leucidal (Leuconostoc/Radish Root Ferment Filtrate) to the other. Before splitting the lotion I had added a few preservative extracts (elderberry, aspen bark, and willow bark.) I also included helichrysum extract, which isn't a preservative, but does help with preserving. So far both batches have held up, but it's too early to tell if the preservative systems are working properly. And without challenge testing, I won't know for sure how safe they are.
I had hoped to test each preservative separately (with the exception of the helichrysum extract, which is not a preservative), but I realized I didn't have enough appropriate containers to do so. I'm also unsure if splitting the batch in two is better than creating two separate batches for testing.
I used Olivem 1000 (Cetearyl Olivate and Sorbitan Olivate) for the emulsifier with Oliwax (Hydrogenated Olive Oil, Olive Oil, Olive Oil Unsaponifiables) to help stabilize the emulsion. Using xanthan gum instead of the Oliwax might have worked better, but I really wanted to try the Oliwax. One of the biggest issues I had was melting the Olivem. If I use it again, I'll need to find a better way to melt it, since my pathetic double boiler set up did not work well.
I'm not sure if the emulsifier hadn't melted properly or wasn't properly blended in, but the Synercide half did not emulsify well. This was the bottom half of the mixture, with the Leucidal half being poured off into another container. The lotion with Synercide is thin and runny, and the water separates out to the bottom when sitting for awhile. I just shake it and use it, but it is gross looking at it when it has separated. The Leucidal lotion has not experienced any of the separation and has a thicker consistency.