Most importantly, herbal supplements are not well regulated in the United States. Studies have shown that 40-50% of herbal supplements do not even contain the supposed main ingredient, and many contain substances that are not listed which may have dangerous side effects2. Another study found that over two thirds of the products tested had substituted other plant species for the plants listed on the label, and a third of products also contained other fillers or contaminants3. A study by the New York State Attorney General of herbal products sold at GNC, Target, Walgreens, and Walmart found that four out of every five products didn’t contain the ingredient they claimed! Fourteen US states and territories have petitioned Congress to regulate the herbal supplements industry.
Erectile dysfunction supplements and other natural remedies have long been used in Chinese, African and other cultures. But unlike prescription medications for erectile dysfunction, such as sildenafil (Viagra), vardenafil (Levitra, Staxyn), tadalafil (Cialis, Adcirca) and avanafil (Stendra), erectile dysfunction herbs and supplements haven't been well-studied or tested. Some can cause side effects or interact with other medications. And the amount of the active ingredient can vary greatly from product to product.