The group treated with the lower concentration of zinc (1 mg/day) did not show an alteration in any of the observed parameters. However, supplementation with a dose of 5 mg/day per rat caused substantial prolonged ejaculatory latency and increased in number of penile thrusting. The other parameters studied remained unchanged indicating uninterrupted libido, sex vigor and performance. Majority of male rats (75 %) showed the prominent actions of sexual behaviour (mount, intromission and penile thrusting) and did not ejaculate within the 15-minute observation period.
There’s some concern that supplements labeled as yohimbe contain different amounts of the active ingredient than the amount that’s listed. The FDA strictly regulates prescriptions containing yohimbine but not supplements. It can be difficult to determine exactly how much active yohimbine is in supplements due to how different growing and distributing variables affect the concentration. These variables can include: the exact type of yohimbe tree bark that is used, what part of the tree the bark is taken from, the maturity of the tree, how fresh the bark is, the processing techniques used to create supplements, and how the supplements are shipped/exported and stored. (16)
Yohimbe is taken by mouth to arouse sexual excitement, for erectile dysfunction (ED), sexual problems caused by medications for depression called selective-serotonin reuptake inhibitors (SSRIs), and general sexual problems in both men and women. It is also used for athletic performance, weight loss, exhaustion, chest pain, high blood pressure, low blood pressure that occurs when standing up, diabetic nerve pain, and for depression along with certain other medications.
However, for most men who experience erectile dysfunction, their overall experience can be improved even further through regular exercise. There are many reasons why exercise improves sexual satisfaction. For one thing, regular, sustained exercise can lead to the release of chemicals called endorphins that are responsible for the so-called runner’s high, and which stimulate the release of sex hormones. Exercise also generally improves mood and imparts a sense of calm afterward, with lower heart rate, lower blood pressure, better digestion, and lower levels of stress hormones.
So, in establishing physiology, pharmacology, clinical results and safety, zinc is a good choice when you look at cost and side effect profile as well as ease of availability and interaction profile with other meds and other medical conditions.  Having said all of this, there is no bulletproof evidence out there guaranteeing that increasing your zinc consumption either in food or via a supplement will improve ED or increase libido.  Even if a patient experiences an increase in testosterone from such a supplementation, this is not a certain gateway to resolution of theses symptoms as there is more to it than just one hormone level.  However for those that are experiencing problems in these areas, it is certainly worth a try for them.  The patient should be mindful however that supplements should be treated like any other medication and trying to increase your testosterone shouldn’t be done without consultation with your doctor and pharmacist.  You should also check for any interactions with any meds or medical conditions before trying any supplement as well.
Stimulant drugs speed up the nervous system. By speeding up the nervous system, stimulant medications can make you feel jittery and speed up your heartbeat. Yohimbe might also speed up the nervous system. Taking yohimbe along with stimulant drugs might cause serious problems including increased heart rate and high blood pressure. Avoid taking stimulant drugs along with yohimbe.
Parameters evaluated in this study are determinants of some important aspects of the male sexual competence. Libido index, intromission and mount latencies are indicators of libido, arousability and motivation. Copulatory efficiency and inter-copulatory intervals are indicators of sexual vigor, while penile thrusting is an indicator of penile erection.[8,11,14,15] Our results showed that the libido index was significantly reduced in the 10 mg/day zinc saulphate treated group. In the same group, majority of the animals (62%) failed to complete their sexual behavioral cycle within the observed period. Though these unsuccessful rats showed the initial steps of the cycle such as licking, physical contacts with the females and few mounts and intromissions, they were inactive at later stages. Therefore a significant reduction of the libido index, number of intromissions, mounts, and ejaculations were observed in the high dose of zinc treated group compared to controls.
Low levels of zinc can be the cause for a variety of health-related problems. Zinc is a key mineral that cells use to metabolize nutrients. Immune function, DNA and protein production, and cell division are all related to zinc levels in the body. Zinc also enables the male body to produce testosterone. Because of this, your levels of zinc may affect erectile dysfunction.