Do you know which desi/ayurveda herb or medicine is best to boost sex drive in men?

A better question...: A better question might be what is causing decreased sex drive. Decreased sex drive can have many, many causes, both psychological and physiological. It would be useful to have some idea about the likely cause before proposing a solution. A good place to start would be a frank conversation with your doctor and a good medical workup to address any potential medical/health issues.