I'm 16 years old boy , and i want to yake viagra (sildenafil) can i ?

I would recommend...: Before taking Viagra (sildenafil), (sildenafil) you should be properly evaluated to decide why you want to or need to take Viagra (sildenafil). For a 16-y-o male, you should not need Viagra (sildenafil) to assist / help erection except someone having severe nerve/ circulation disorders. But, clinically, I suspect you may have overindulged in sex - masturbation or intercourse, to the point you have overrun yourself. If so, slow down... Best wish...