Hello.during sex my penis didn't come hard.doctor advise me to take herberex tablets but this tablet work only for timing and i want penis hard forever?

Sex herbs: In your twenties, there is no reason you should suddenly be developing impotence problems. This could come from medication, poor blood flow, diabetes, or vascular diseases. I would start with discussing this with your family physician. As to the herb, there is no herb I know of that reliability helps with maintaining erection. Another possibility is trust issues with your sexual partner.