Synthol is a substance some people use to make their muscles look bigger. But it’s not safe. It can cause infections, hurt the muscles, and even damage the skin. Using it is against the law in many places, and it can be dangerous. It’s much better to build muscles by eating well and exercising regularly. If you want help, talk to a doctor or fitness expert instead. Your health is important, and synthol is not a good way to get strong muscles.