What it is
E422 (glycerol, also called glycerine or glycerin) is a colourless, odourless, sweet-tasting liquid. Modern industrial production is overwhelmingly plant-based — a by-product of biodiesel production from vegetable oils, or from soap-making with plant fats. Historically and in some smaller-scale production it came from animal fats (tallow).
Why it matters
Very widely used as a humectant (moisture-retaining agent) in baked goods, low-fat ice cream, ready meals, cosmetics, toothpaste, and pharmaceutical syrups. The food-grade product is colourless and labels rarely indicate the source.
What to do
Default assumption is vegan in modern food. If the product is a small artisan brand, traditional formulation, or specifically pharmaceutical, ask the manufacturer to confirm vegetable origin.