Because salsa is such an intense dance, men should wear clothes that are comfortable and breathable. This usually means a light, collared shirt with dress pants or jeans that allow the legs to move about freely.
Occasionally, a salsa club has a certain dress code dancers need to adhere to, so people need to call ahead to find out what is acceptable. If the dress is casual, comfort is the most important thing; men can wear light clothing such as a T- or polo shirt with jeans or shorts. In dressier clubs, men should still wear comfortable and breathable clothing, but a light button-down shirt with dress pants is more fitting.
For those who tend to sweat a lot while dancing, it is a good idea to bring an extra shirt in case an emergency change is required. Bringing a handkerchief is also recommended to wipe away excess sweat discreetly.
Don't wear sneakers or rubber-soled shoes to a salsa club because they restrict your movement and can add stress to your joints. Few salsa clubs allow these types of shoes anyway because they muck up the floor. Special salsa-dancing shoes work the best, but any dance shoes with suede or leather soles allow you to move and spin effectively.