Much of the evidence shows high rates of vitamin D deficiency in patients with erectile dysfunction. In fact, one study of 3,400 participants found that men with vitamin D deficiency were 32% more likely to have trouble with erections when all other risk factors were controlled for. It’s a little on the nose that you need vitamin D for your “D,” but hey—science can be funny too.
Ginseng. Korean red ginseng has long been used to stimulate male sexual function, but few studies have tried systematically to confirm its benefits. In one 2002 study involving 45 men with significant ED, the herb helped alleviate symptoms of erectile dysfunction and brought "enhanced penile tip rigidity." Experts aren't sure how ginseng might work, though it's thought to promote nitric oxide synthesis. "I would recommend ginseng [for men with ED]," says Espinosa. Discuss with your doctor before taking it since ginseng can interact with drugs you may already be taking and cause allergic reactions.
Red Ginseng — One small randomized trial found evidence that red ginseng may offer modest improvements in ED symptoms (as compared with placebo). A meta-anaylsis published in the British Journal of Clinical Pharmacology states, “Traditionally red ginseng has been used to restore and enhance normal well-being, and is often referred to as an adaptogenic….Possible mechanisms of action of red ginseng include hormonal effects similar to those of testosterone. Others have postulated that red ginseng might induce relaxation of the smooth muscles.” (5)
This is another herb used for centuries in Chinese medicine to treat erectile dysfunction and low libido. A study from 2008 found that the herb blocks the effects of an enzyme that restricts blood flow to the penis. Researchers believe horny goat weed, also known as epimedium, acts as a natural phosphodiesterase inhibitor, the same action as seen in erectile dysfunction drugs such as Viagra or Cialis. However, the research indicated that horny goat weed can work more effectively and cause fewer side effects than the drugs.
Just because a product claims to be natural doesn't mean it's safe. Many herbal remedies and dietary supplements can cause side effects and dangerous interactions when taken with certain medications. Talk to your doctor before you try an alternative treatment for erectile dysfunction — especially if you're taking medications or you have a chronic health problem such as heart disease or diabetes.