Silipints use platinum-cured silicone which is the cleaner way of curing silicone. Combined with our use of 100% food-grade silicone, our standards pass not only FDA-ratings in the US but even higher for LFGB standards in Germany.
Knock-off silicone often uses cheap additives or fillers because platinum-curing is more expensive. However, those fillers are usually toxic and unsafe - especially when being used with food and beverage. Also, knock-off silicone with these additives in it could have a very pungent smell similar to formaldehyde.