https://www.lotioncrafter.com/
This is a great website if you make products yourself.
Go to the “Preservatives” section on the left side.
A good number of the preservatives have undergone chemical processes. Not like toxic chemical processes but stuff like heating, sythnesis, decantation, etc.
The Potassium Sorbate or Willow Bark Extracts are the ones I’ve used since they’re rather pure mixtures. Just follow the ratios they suggest on the description, and check for any possible denaturing of the flaxseed gel.