# The Hardest Substance in the Human Body and Other Strong Elements Your body is an incredible machine, built with various strong and resilient materials. Among these, the hardest substance is tooth enamel. Enamel is the outermost layer of your teeth and is composed of 96% densely packed minerals, making it tougher than steel and earning a 5 on the Mohs Hardness Scale. This hardness helps protect your teeth from daily wear and tear, whether you're chewing tough foods or drinking hot beverages. Besides enamel, your body has other strong components. Bones, for instance, are also quite tough, ranking similarly to enamel on the Mohs scale. The jawbone and femur are considered the strongest bones in your body. Bones are made of living tissue, primarily collagen and calcium phosphate, which give them strength and flexibility to absorb stress. Muscles, ligaments, and tendons are also strong but not as hard as enamel or bones. Muscles are made of thousands of flexible fibers that help move your bones and protect your organs. Ligaments are strong bands of connective collagen tissue that hold your joints together, while tendons connect muscles to bones and are more flexible than ligaments. In summary, while tooth enamel is the hardest substance in your body, bones, muscles, ligaments, and tendons all play crucial roles in providing strength and resilience to your body.