Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.


The neurovascular mechanism of erection is complex and involves multiple factors including hormones, neurotransmitters, elements of the autonomic nervous system (sympathetic and parasympathetic) and vasodilators such as NO. The common causes of ED include psychogenic disturbance with failure to relax cavernous smooth muscle, arterial insufficiency as a result of atheromatous disease, damage to the parasympathetic nervous system, spinal cord injury, diabetes or following pelvic surgery such as radical prostatectomy, radical cystectomy or bowel resection [4]. It is important to note that cavernous nerves are unique in that although they belong to the autonomic nerves system they do not release either acetylcholine (Ach) or norepinephrine; however, they release NO in the penis. NO relaxes the smooth muscle of the corpora cavernosa via cyclic GMP (cGMP), allowing expansion of the cavernosal lacunar spaces, blood flow and erection. Thus, NO is not a direct dilator of the smooth muscle of cavernosal bodies, but it is an important mediator in this process. Erectile function may also be adversely affected by cigarette smoking, excess alcohol consumption, obesity and systemic diseases such as mononucleosis, hepatitis, HIV and cancer. Some men are prone to develop an erection that fails to subside after ejaculation (ie, priapism). The condition is associated with sickle-cell disease and leukemia, or may be a result of intracavernosal injection of drugs such as prostaglandin E1 [4]. Peyronie’s disease causes a physical bend in the erect penis and also contributes to ED.

ED can be caused by a handful of things, but one thing’s for sure: You need a healthy supply of the neurotransmitter nitric oxide (NO) to get and maintain an erection. NO is produced in nerve tissue and helps jolt your Johnson by relaxing the smooth muscle so blood can fill the penis. After the initial release of NO, your body releases a cascade of chemicals—including more of the neurotransmitter—to help keep you hard and happy, according to a study in the Proceedings of the National Academy of Sciences.
Some studies carried in and outside Uganda show that some of these plants listed in the management of sexual impotence and ED may be potent. Some of these medicinal plants are regarded as traditionally aphrodisiacs, implying that they have ability to increase sexual desires. For instance, Cola acuminata fruits are widely used herbal remedies in ED and are harvested from the forests of Democratic Republic of Congo. The Cola acuminata fruits contain about 2% catechine-coffeine (Colanine)7. The roasted seeds in Europe are used as strong stimulant, in addition to the treatment of migraine, neuralgia, diarrhoea and stimulant or cardiotonic, loss of appetite, antidepressant and melancholy (severe form of depression)7. Coffee is drunk for certain migraine, nausea, resuscitation and diuretic7. Coffee is a famous stimulant used world over as a beverage. However, the wild coffee species are more popular in treating ED and are believed to contain more alkaloids (caffeine). Coffee is further reported to be a nervous system stimulant (Pampalona-Roger, 2000). Cannabis sativa (Marijuana) is smoked by mentally sick and impoverished men7. C. sativa is like morphine, it is an opioid analgesics. Allium sativum (garlic) is used in treatment of diabetes, high blood pressure, prevention of arteriosclerosis (hardening of the arteries and is one of the causes of ED)7. Garlic reduces blood sugar levels and blood cholesterol levels which are the direct causes of ED if not checked. The Zingiber officinalis (ginger) volatile oils from the rhizome are used for stimulating the nerves and making then sensitive7. Capsicum frutescens in many African cultures is a known powerful stimulant and carminative24. Capsicum frutescens (chilli) contains enzyme capsaicine that helps in blood clotting (fibrinolytic) and people who consume C. frutescens seldom suffer from heart attack. In addition, the pharmacological tests showed that the capsaicin chemical compound from Capsicum frutescens acted like powerful stimulant of the receptors participating in circulatory and respiratory reflexes24.
According to the Cleveland Clinic, “because erectile dysfunction is caused by a complex set of psychosocial, neurologic, and vascular factors, a specific cause in a patient may remain ambiguous.” The root causes are often related to a blockage or dysfunction of blood vessels. For example, ED can be due to conditions like atherosclerosis or diabetes, hormonal imbalances or problems related to mental health. It’s been found that common causes typically include one or more of the following factors: (2)
DHEA. Testosterone is essential for a healthy libido and normal sexual function, and erectile dysfunction sufferers known to have low testosterone improve when placed on prescription testosterone replacement therapy. Similarly, studies have shown that taking over-the-counter supplements containing DHEA, a hormone that the body converts to testosterone and estrogen, can help alleviate some cases of ED. But DHEA can cause problems, including suppression of pituitary function, acne, hair loss and its long-term safety is unknown, says McCullough. For this reason, many experts discourage use of the supplements.
What are the alternatives to viagra? Erectile dysfunction, when a man cannot achieve or maintain an erection, is a common condition that causes much distress. Viagra is just one of several drug treatments that can help relieve the problem. Other methods and treatments can help, too, including alternative herbal remedies that people may wish to try. Read now

The basis of ED herbal therapies is that they are anti-inflammatory, antioxidant and immunomodulatory, and can stimulate testosterone production. On the other hand, the synthetic drugs act via NO. The principal mediator of the relaxation of corporal smooth muscle of the penis has been shown to be NO, which is released mainly from parasympathetic nerves and endothelium [13]. NO is believed to relax the corporal smooth muscle by activating soluble guanylate cyclase to increase cGMP content [14,15]. Penile rigidity depends on maximizing inflow of blood while minimizing outflow [6]. The increased blood flow in the cavernous sinuses puts pressure on the walls of the surrounding veins, causing the lumen of the veins narrow, temporarily interfering with the flow of blood but causing tumescence. Normally, the parasympathetic nerve produces Ach. Ach acts on muscarinic receptors and nicotinic cholinergic receptors. When the parasympathetic nerve is stimulated, preganglionic neurons release Ach at the ganglion, which acts on nicotinic receptors on postganglionic receptors. Postganglionic neurons then release Ach to stimulate muscarinic receptors of the target organs. The muscarinic receptor M3, present in the endothelial cells and smooth muscle, is activated, and the M2 receptor in the heart may also be activated. This may result in the production of Ach, which can cause endothelial cells to produce NO. Ach released from postganglionic parasympathetic nerves acting through G-protein-mediated muscarinic receptors and nicotinic cholinergic receptors helps to release NO. Normally, M1, M2 and M3 receptors are found in secretory glands, heart, smooth muscle and endothelial cells, respectively. M1, M2 and M3 receptors cause activation of phospholipase C and generate inositol trisphosphate and diacylglycerol, which increase calcium. Activation of M4 may inhibit adenylate cyclase, decreasing the messenger cyclic AMP. This mechanism may be involved in the relaxation and contraction of cavernosal smooth muscle cells.
Phytolacca dodecandra leaves and roots are pounded and smeared on ripe banana and then the ripe banana roasted before being eaten for treating erectile dysfunction. However, care has to be taken Phytolacca dodecandra is poisonous. Cola acuminata fruits are mixed with other plants in Benin to treat primary and secondary sterility24. Cola acuminata is also said to be diuretic and laxative when administered orally24. Some Acacia species are regarded as aphrodisiacs in Niger2. Cassia species have high repute as drugs and poisons. For instance, Cassia sieberiana is used urinary problems, impotence and kidney diseases in Mali24. In Burkina Faso, Cassia occidentalis is used as a stimulant24. Flueggea virosa is famous medicine in African cultures. Flueggea virosa used in sterility, aphrodisiacs, stimulant, rheumatism, arthritis, spermatorrhoea, kidney and liver problems among many other diseases treated17,24.
Tongkat Ali (Eurycoma longiflora) (Figure 7): this native plant found through SE Asia is used as an Aphrodisiac since 1996 (5). It has to be used regularly and works by enhancing the testosterone and cGMP production. Benefits are felt gradually over a period of time, mainly because it enhances the natural biological synthesis of testosterone. When the level is increased, health and vitality are restored. In studies on Mice, Tongkat Ali increases the number of times and duration of sexual performance of the animals under study (8) with testosterone levels increasing up to 440% in some animals. In a recent study on humans, 62% of subjects showed an increase of the free testosterone index indicating it’s biostimulatory effect on steroidogenesis. It has also been shown to increase sperm concentration and motility and increases energy in the individual by enhancing ATP production by 60% thru oxidative phosphorylation.
The key respondents were mainly old men, male traditional healers, traditional birth attendants and young women and all in total about 160 traditional healers were interviewed. To document male related ailments men are particularly more knowledgeable and most men share their problems with men. In addition, the old men and healers are the ones in charge of administering these herbal remedies. Young women through the informal discussions, interviews and market surveys are particularly more dynamic in the use of herbs for themselves, husbands and children besides being the most active reproductive age group. The medical ethnobotanical data collected has been analysed, medicinal plants from the study areas have been listed and methods of administering the herbal drugs were also documented. In checking for the proper updated naming, spellings and authors of the medicinal plants, besides using voucher specimens in Makerere University Herbarium, several reference books were used1,3,9,15,16,20,22,27.
Epimedium extract (Horny Goat Weed) (11), (Figure 9): the Chinese refer to this herb as ‘yin yang huo’, which has been loosely translated as ‘licentious goat plant’; hence, its common name is well known as ‘horny goat weed’ by many Western cultures. Scientifically, studies have shown that Epimedium may restore low levels of both testosterone and thyroid hormone, bringing low levels back to their normal levels (5), which may account for some of its benefits in improving sexual libido. Other benefits to Epimedium involve increased muscle mass. Used for fatigue and aging, And vasodilatation effect; thus, most frequently used in treatment of sexual dysfunction in Traditional Chinese Medicine (12). The active substance from horny goat weed was reported by Xin Zhong Cheng at Beijing Medical University as Icarin—acts by increasing sexual activities and ICP levels in castrated rats after long term oral administration. It has no effects on serum testosterone level in castrated rats after long term oral administration. Instead Icariin increases nNOS and iNOS mRNA and protein expression in the corpus cavernosum after long term oral administration and hence may have long term efficacy on erectile dysfunction after oral administration.

In the East, many herbal tonics and preparations are used to assist the aging male improve his ability to have sexual drive or perform penetrative sex by increasing sexual stimulation, erectile, ejaculatory, orgasmic and other responses for sexual function and satisfaction. Currently available herbals, tonics and therapies range from Tongkat Ali, Ginseng, Tribulus etc. Those that act as testosterone releasers have some value especially if the male has andropause and those containing some pick-me-ups II and energizers like ginseng help the tired and fatigued male and possibly those with asthenia. Deer horn contains growth factors and taking these may help improve nocturnal erections in the male with somatopause. Popular in historic Singapore were remedies such as “Penis Soup II” (Figure 2) and Snake Meat, whilst Surabaya was known for Cobra meat (Figure 3) and Cobra Blood which had claims of improving erectogenic prowess-these myths including that of taking dog, cow, wild boar, bull and ostrich testicles (Figures 10,​,11)11) are mainly Village doctor remedies still being practiced widely in the developing regions of Asia. In China, the horny goat weed (Figure 9) is currently still popular and may have some scientific merit (11) for enhancing sexual drive.
L-arginine: L-arginine is an amino acid present in the proteins of all life forms. Also, referred to as arginine, this amino acid is required to carry out the synthesis of nitric oxide, which relaxes the blood vessels and allows more blood to flow through arteries (13). L-arginine has shown promise in the treatment and prevention of cardiovascular disease and in the treatment of male infertility (13). With its anti-oxidant properties, L-arginine can be an integral part of any sexual wellness supplement.
Currently, there are four orally active drugs are available to treat ED. These include: sildenafil citrate (Viagra [Pfizer, USA]), vardenafil hydrochloride (Levitra [Bayer, Germany]), tadalafil (Cialis [Eli Lilly, USA]) and avanafil (Stendra, Spedra [Vivus Inc, USA]). These drugs inhibit the enzyme phosphodiesterase type 5 (PDE-5), which is responsible for the hydrolysis of cGMP. PDE-5 inhibitors and cGMP act as effectors of dilation of smooth muscle of cavernosal bodies. PDE-5 inhibitors are contraindicated in patients taking any kind of nitrate therapy for angina, and may not be appropriate for men with certain health conditions, such as severe heart disease, heart failure, history of stroke or heart attack, uncontrolled high blood pressure or diabetes, and patients with pigmental retinopathy. PDE-5 inhibitors are less effective in men with diabetes and men who have been treated for prostate cancer. PDE-5 inhibitors are also not effective in men with retinitis pigmentosa, a genetic disease involving PDE-5 deficiency. The common side effects of PDE-5 inhibitors include gastrointestinal upset, headache, nasal congestion, back pain and dizziness. The PDE-5 inhibitors may interact with other medications including antihypertension drugs. Nonetheless, the PDE-5 inhibitors are generally safe and effective for most men. The primary mechanism of action of these drugs is through the mediation of NO. NO is one of the key molecules involved in ED. It is a short-lived, highly permeable, pleiotropic, gaseous molecule, secreted from the postganglionic cavernosal parasympathetic nerves, endothelium of the cavernosal blood vessels, platelets in the cavernosal sinuses and phagocytic cells (monocytes, macrophages and neutrophils). NO acts on platelets to inhibit platelets adhesion and aggregation. NO causes relaxation of the smooth muscle of the cavernosal blood vessels of the penis, leading to vasodilation, tumescence and stimulation. Release of NO in the corpus cavernosum of the penis during stimulation activates the enzyme guanylate cyclase, which results in increased levels of cGMP, producing smooth muscle relaxation in the corpus cavernosum and resulting in increased blood flow (5). NO is mainly produced from cavernosal nerves, which are nonadrenergic, noncholinergic nerves within the penis, and acting via its second messenger cGMP. It has been suggested that maintaining normal body weight and mild exercise, as well as dietary supplementation of folic acid, zinc, calcium, vitamin C, vitamin E and L-arginine, a precursor of NO, can support the biochemical pathway leading to NO release [6]. NO is an effector molecule that is involved in a number of intracellular functions such as vasorelaxation, endothelial regeneration, inhibition of leukocyte chemotaxis and platelet adhesion [7]. A small proportion of autonomic nerves do not release either Ach or norepinephrine [8]. For example, the cavernous nerves predominantly release NO in the penis. The exact mechanism is not known, but it is believed to be through increased intracellular calcium. Another gaseous molecule produced in the corpora cavernosa is hydrogen sulphide (H2S), which is also known to be involved in erectile function [9]. H2S activates ATP-sensitive potassium channels in smooth muscle cells. Some reports indicate that NO acts in large vessels and H2S in small vessels. A high level of tumour necrosis factor-alpha has been shown in ED patients [10]. Although current ED therapies using PDE-5 inhibitors are safe and effective, approximately 40% of ED patients do not respond to currently available treatment [11,12]. For these patients, herbal therapy may be useful.

The field visits and excursions were arranged with the healers for places far from their homesteads or took place concurrently with the interviews and discussions. When going to the forests, game reserves or other areas where herbalists collect plant specimens, prior arrangements were made with the community leaders and park staff. This was done with individuals or groups depending on where the herbs are collected. In the shared areas such as the fishing villages, or the multiple use areas, group and individual excursions were conducted. Some of the medicinal plants that are harvested from distant places such as the Democratic Republic of Congo, other districts and unsafe areas within the reserve were not collected but their local names were recorded. The data collected were to supplement the information on plant names, plant parts used, collection of the herbarium voucher specimens and conservation status of these medicinal plants. The medicinal plants collected were given the voucher numbers and then later identified in Botany Department herbarium of Makerere University.
The key respondents were mainly old men, male traditional healers, traditional birth attendants and young women and all in total about 160 traditional healers were interviewed. To document male related ailments men are particularly more knowledgeable and most men share their problems with men. In addition, the old men and healers are the ones in charge of administering these herbal remedies. Young women through the informal discussions, interviews and market surveys are particularly more dynamic in the use of herbs for themselves, husbands and children besides being the most active reproductive age group. The medical ethnobotanical data collected has been analysed, medicinal plants from the study areas have been listed and methods of administering the herbal drugs were also documented. In checking for the proper updated naming, spellings and authors of the medicinal plants, besides using voucher specimens in Makerere University Herbarium, several reference books were used1,3,9,15,16,20,22,27.
Tongkat Ali (Eurycoma longiflora) (Figure 7): this native plant found through SE Asia is used as an Aphrodisiac since 1996 (5). It has to be used regularly and works by enhancing the testosterone and cGMP production. Benefits are felt gradually over a period of time, mainly because it enhances the natural biological synthesis of testosterone. When the level is increased, health and vitality are restored. In studies on Mice, Tongkat Ali increases the number of times and duration of sexual performance of the animals under study (8) with testosterone levels increasing up to 440% in some animals. In a recent study on humans, 62% of subjects showed an increase of the free testosterone index indicating it’s biostimulatory effect on steroidogenesis. It has also been shown to increase sperm concentration and motility and increases energy in the individual by enhancing ATP production by 60% thru oxidative phosphorylation.
“Obecalp” is “placebo” spelled backwards. It might help – treatment with inactive placebos (inert substances used in evaluation of new drug treatments) works about one-third of the time in scientific studies when patients don’t know they’re getting a fake drug. Placebos are generally safe since they contain no known active agent. (However, I personally never give patients inactive placebos, and many physicians regard them as unethical.)
If you can't take one of these oral medications, your physician may have you try Caverject (alprostadil for injection), a hormone that you inject into your penis using a fine needle, or Muse (alprostadil urogenital), a tiny suppository that you insert into the tip of the penis. Both of these will bring on an erection within five to 15 minutes without sexual stimulation.
Tribulus Terrestris is the fruit of the Zygophyllaceae plant and it grows primarily in North China. It is a well-known aphrodisiac with records that trace back to ancient times. There are plenty of animal experiments that verify the effectiveness of Tribulus for improving erectile function. These effects are mostly due to its androgen enhancing ability, namely increasing testosterone levels. Though testosterone doesn’t directly cause an erection, it does play a role. Erection is made possible by many factors, but mostly it's through receptors on cells lining our arteries that stimulate a chain reaction that relaxes the blood vessels that go to the penis, allowing blood flow to get in. Low testosterone is often associated with overall poor metabolic and cardiovascular health. When the test is low, estrogen is usually high, leading to oxidative stress and calcification of the arteries, including the penis, restricting blood flow to the penis. So, improving testosterone levels, and improving overall metabolic function, while reducing oxidative stress is a good plan for improving overall sexual function and erection.
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