I don't know if this is helpful or not, but just as a comparison, looking at the different ingredients of two M&P bases sold at WSP:
All Natural Clear Base:
Sodium Cocoate, Sodium Palmate, Ricinus Communis (Castor) Seed Oil, Carthamus Tinctorius (Safflower) Seed Oil, Glycerin, Water, Sorbitol, Sorbitan Oleate, Glycine Soja (Soybean) Protein.
Pro Base Clear:
Sorbitol, Water, Propylene Glycol, Glycerin, Sodium Stearate, Sodium Laureth Sulfate, Sodium Myristate, Sodium Laurate, Triethanolamine.
M&P bases can technically say they are natural if they do not use syn dets and other synthetic ingredients such as Propylene Glycol, Sodium Laureth Sulfate, etc. Is it really 100% natural - no. But comparing the bases, the "All Natural" one is definitely the much more natural of the two.
I've worked with both of the bases I mentioned - Bases labelled "Natural" tend to be more moisturizing, more slippery, softer, and don't last as long.