Sweet whey

Sweet whey comes from cheeses made with rennet rather than acid or bacterial cultures, leaving it with minimal fermentation activity.

• Low fermentation origin — because it's a byproduct of fresh cheese production rather than aged or cultured dairy, histamine levels tend to stay low

• Different from acid whey — acid whey is a byproduct of yogurt or quark production; the two differ in their production process, and sweet whey from rennet-based cheeses is generally considered the more histamine-friendly form, though direct comparisons in the literature are limited

If you encounter sweet whey as an ingredient, it's typically one of the less concerning dairy components from a histamine perspective.