Gelatin (also: E441, Hydrolyzed collagen)
A protein derived from boiling animal bones, skin, and connective tissue. The vast majority of commercial gelatin in Western markets comes from pork. Plant-based alternatives (agar, pectin, carrageenan) exist but must be specified on the label. Without "halal gelatin" or "fish gelatin" annotation, treat as not halal.
Example: Yogurts, marshmallows, gummy candies, frosted cereals, gel capsules, some cream cheeses.
Related:Is gelatin halal?, Hidden haram ingredients
Glycerol (also: Glycerin, E422)
A sweetener, humectant, and solvent used in countless foods, medications, and personal care products. Can be derived from plant oils (halal) or animal fats including pork (haram). Unless the label specifies "vegetable glycerin" or carries halal certification, the source is uncertain.
Related:E422 details