L-arginine. L-arginine is an important amino acid that the body needs to build proteins. Because L-arginine has been shown to improve blood flow, some alternative practitioners have recommended that the supplements be used to treat ED. The Natural Medicines Comprehensive Database, which is a reliable authority on alternative medicines, says L-arginine is possibly effective for treating erectile dysfunction. But Harris warns that "although this supplement could improve blood flow, side effects can be dangerous." L-arginine can cause an allergic reaction or worsen asthma in some people; it can also lower blood pressure.
And just because you’re using a “natural” herb doesn’t mean you won’t feel any side effects. Ginseng can cause hypoglycemia or bleeding in some people, and at high doses puncturevine can damage the kidneys. Plus, the FDA has found that a lot of supplement companies make sure their erection-enhancing products actually produce erections by tossing in some Viagra off-label. If you really need it, it’s probably better–and safer–to go see your doctor for a prescription.
Yohimbe A number of clinical trials have shown that the primary component of this bark from an African tree can improve sexual dysfunction associated with selective-serotonin reuptake inhibitors (SSRIs) used to treat depression. This herb has been linked to a number of side effects, including increased blood pressure, fast or irregular heartbeat, and anxiety. Yohimbe shouldn't be used without a doctor's supervision.