Colin Sanders 
From a biological perspective, tallow would be described as an animal-derived fat with specific physical and chemical properties.
Tallow is a rendered form of fat, no primarily obtained from cattle or sheep, consisting predominantly of triglycerides (three fatty acid chains attached to a glycerol backbone).
Tallow, a purified fat from cattle and other large mammals, was once the main feedstock used to make soaps and many other cosmetic ingredients. This changed with the arrival of BSE, or mad cow disease, in the late 1980s and early 1990s. BSE is a brain disease that affected some cattle herds and caused a great deal of concern because it was linked with a similar disease in humans. This led to some dramatic changes in the way animal-derived ingredients are handled in all kinds of products, including cosmetics.
Until recently, EU law required cosmetic products to list 24 specific fragrance allergens on their packaging if they were present above very low levels. These rules were designed to help people who are sensitive to certain ingredients avoid products that might cause them problems. However, as our understanding of allergies has improved, it’s become clear that more substances can cause reactions than were previously listed.
Etidronic acid, also known as HEDP, is a type of phosphonate compound that acts as a chelating agent. In plain English, this means it’s very good at grabbing hold of metal ions—like calcium, iron, and copper—and stopping them from interfering with the rest of the ingredients in a product. This is useful in personal care because even tiny traces of metals can spoil the appearance, texture, or shelf life of things like creams, shampoos, and soaps. Etidronic acid helps keep these products stable and looking fresh for longer.