One of the main actions of yohimbe bark is alpha-2 antagonism (this is why it’s also sometimes called an “alpha-2 blocker”). This means that it can impact sympathetic nervous system activity and increase the release of adrenaline (or noradrenaline). This is because it blocks alpha-2 receptors in the brain stem. (4) Other types of alpha-2 agonists medications work in a similar way. They affect the central nervous system by altering release of certain neurotransmitters and dilating blood vessels. This increases alertness, circulation and other physiological processes.
Magnesium helps regulate levels of calcium, zinc, and other vitamins and minerals. It also helps the body produce energy and contributes to proper organ function. Most people don’t develop a genuine magnesium deficiency, even if they don’t get enough of the mineral in their diets, according to the University of Maryland Medical Center. A true magnesium deficiency, however, may increase the risk of erectile dysfunction.
Two years ago I took regular Niacine for about a year to lower LDL and increase HDL. I did not want to take Statins because of its side effects. I was being monitored by my Dr. because of the effect on liver enzymes. I took 1.5 gr together with Phytosterols. The treatment was effective and the only side effect were the flushes which I found could be eliminated by having 500 mg at the end of each of the 3 main meals. I stopped treatment for a year or so, but now the Dr. suggested I start taking Niacine. or Statins. I chose Niacine (Nicotine Acid) and started with 500 mgs for 3 days; increased it to 1000 mgs. for 4 more days, until I increased it to 500 mgs x 3 for a total of 1.5 grms/day taking 500 mgms/meal. I started noticing my gradual decrease in libido this time almost inmediately. I do not take any other medicines as such I'm definitely inclined to blame Niacine because I have taken Phytosterols for 3 years and my libido was fine. I'm a senior. Hope this will help!

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.