A medical doctor has approved Viagra as one tablet about 1 hour before sexual activity. Men who are currently using medicines which contain nitrates should not use Viagra because taken together they can lower the blood pressure too much. One 1999 study discovered that oral L-arginine was no much better than a placebo in treating ED, but another study found some evidence that high doses of L-arginine can improve blood circulation and help ED. Potential side ramifications of use include nausea, cramps, and diarrhea. Before taking any ED medication, tell your doctor about any preexisting health conditions you have. You should also discuss some other drugs or supplements you’re currently taking.