A conflicting study of 22 subjects found that a 100mg daily dose of yohimbine for 30 days did not significantly improve penile rigidity. Three subjects experienced a notable increase in penile rigidity and twelve subject experience a partial increase in rigidity.  These findings do not completely discount the use of yohimbine to treat erectile dysfunction, but do suggest the compound's effects, even at very high dosages, will cause varying responses across a similar population.
With the erectile dysfunction (ED) market expected to reach 3.4 billion dollars (USD) by 2019, this is a lucrative area to invest in, and not much grabs the attention of a guy watching a commercial during a Monday night football game than the promise to easily cure this problem with one pill as needed. But is this the answer for everyone? What causes ED? For the guy with no apparent risk factors like depression or diabetes, hypothyroidism, injury or stress issues, erectile dysfunction or loss of libido (which don’t necessarily go hand in hand) can be confusing and frustrating for a guy as well as his partner.
The results, published earlier this month, show that the 80 men in the study with moderate or severe erectile dysfunction (ED) and high cholesterol reported an improvement in their ability to maintain an erection after supplementing their diet with niacin. The 80 men who took a placebo pill, who also began the study with only mild ED, did not experience a change in their symptoms, the researchers said.
Data from the Florida Sexual History Questionnaire collected at each time period (baseline, 5.4 mg tid and 10.8 mg tid) are presented in Table 6. Three patients (two responders and one nonresponder) did not complete the entire questionnaire for each study period and were excluded from the analyses. Thus, data in the table and statistical analyses are based on the responses of seven responders and eight nonresponders.
According to the Centers for Disease Control and Prevention, ingesting levels of zinc in excess of the recommended dietary amount will result in diarrhea, vomiting, and stomach cramps. The maximum amount of daily zinc consumption recommended is 40 milligrams per day. Symptoms of too much zinc intake include nausea and headaches. If you have reason to suspect you have ingested too much zinc, contact a medical professional.