Onejaw ad: Onejaw

It's not the hardness. It's how many times you bite. The masseter isn't a bicep. You're not pumping it up, you're building the tonic, fatigue-resistant end of the muscle, the part that holds your jaw where it should sit all day. That comes from accumulated reps, not peak force. Chew something car-tyre hard and you fatigue in seconds and recruit your neck to help. Chew something firm for a real session and you're actually training the function.