Is zinc alone enough to boost testosterone?

Sorry, no: It also is not well tolerated as a long-term supplement (due to its "metallic" taste). Should discuss w/your dr, and likely check blood level if think truely are hormone-low. Otherwise, increased muscle activity (like weight lifting) can improve endorphins / self-esteem / function, and may address what you are concerned about.

Doubtful: Unless you are ill from a zinc deficiency, rx testoserone is the only proven way to treat hypogonadism. If you do not have that condition, then staying healthy is the best option to keep all of your hormones optimized: healthy diet, exercise, sleep, no smoking...Anything, minimal alcohol use, no illicit drug use, staying well hydrated.