Arginine and Select Phytonutrients Enhance Libido
A Natural Approach to Enhancing Sexual
Libido and Performance
A normal sexual response in men and women
begins in the presence of sexually oriented stimulation. When
the mood is right, the body responds by releasing a cascade of
chemicals that direct the flow of blood into the sexual organs.
In women, this leads to engorgement and lubrication of the
organs as the body prepares for intercourse. In men, this rush
of blood is directed into a pair of pockets, known as the corpus
cavernosum, that run inside the shaft of the penis. This inflow
of blood is critical to the enlargement and stiffening of the
This engorgement is triggered by a unique neurotransmitter
called nitric oxide (NO). Nitric oxide, in turn, stimulates the
production of another signaling enzyme called cyclic guanosine
monophosphate, or cGMP for short. Under normal circumstances,
cGMP signals the smooth muscles surrounding the arteries of the
penis to relax and allow blood to flow into the penis. Any
condition that interferes with the signaling of these messenger
enzymes can quickly lead to the breakdown of the entire process
and cause impotence.
According to the National Institutes of Health, impotence, or
erectile dysfunction, is defined as the inability to attain or
sustain an erection adequate for satisfactory sexual
intercourse. Experts believe impotence affects between ten and
fifteen million American men. In 1985, the National Ambulatory
Medical Care Survey counted 525,000 doctor-office visits for
erectile dysfunction, and that number has greatly increased
Impotence usually has a physical cause, such as disease, injury,
or drug side effects. Any disorder that impairs blood flow in
the penis has the potential to cause impotence. It occurs as men
age: about five percent of men at the age of forty, and between
fifteen and twenty five percent of men at the age of sixty-five
experience impotence (Fig. 1). Yet impotence is not an
inevitable part of aging.
In 1998, the FDA approved the prescription drug Viagra (sildenafil
citrate) as a treatment for men suffering from non-organic
impotence due to conditions such as diabetes, radical
prostatectomy, spinal cord injury, and vascular disease. Viagra
was originally investigated as a potential anti-angina
medication based on its ability to release nitric oxide and
increase blood flow to the heart. Although Viagra failed as a
heart medication, researchers in London became excited when men
in the clinical trials reported the frequent occurrence of
unaccustomed erections and improved sexual performance.
Following this serendipitous finding (and five years of clinical
trials), Viagra was finally granted approval as a treatment for
men who had difficulty achieving erections because of conditions
such as diabetes, radical prostatectomy, spinal cord injury, and
Viagra was found to help men achieve and maintain erections by
(1) enhancing the effects of the neurotransmitter nitric oxide
(NO), and (2) maintaining higher levels of the enzyme cGMP, the
two key players in penile erection. Viagra does this by
selectively inhibiting the enzymes that destroy cGMP, leading to
elevated cGMP levels. This, in turn, increases blood flow to the
genitals and leads to stronger erections and intensified
Viagra was found to help eighty percent of men suffering from
non-organic impotence. Additionally, Viagra also seems to
enhance sexual performance and enjoyment, and reduce the latent
period between erections, even in men who have no dysfunction.
Viagra has also gained a reputation with women, which makes
sense when one considers that the clitoris, which is
structurally similar to the penis, becomes engorged with blood
during sexual arousal. Viagra may provide similar benefits to
women, stimulating the release of NO, encouraging blood flow and
enhancing sexual sensation and orgasm.
Serious Side Effects of Viagra
While Viagra is effective for millions of men, the side effects
for many —facial flushing, headaches, and indigestion— are too
troublesome for continued enjoyment. And, more seriously, soon
after its introduction, vision problems began to surface in men
taking Viagra, leading to warnings for people with retinal eye
conditions, such as macular degeneration or retinitis pigmentosa,
to use the drug only with caution.
In addition to eye problems, both the FDA and the manufacturer
began to issue warnings against taking Viagra with any
nitrate-based cardiac medications (i.e., sublingual
nitroglycerin tablets, nitroglycerin patches, etc.). Doctors
were warned that heart patients should not be treated with
nitroglycerin if the patient had used Viagra in the previous
twenty-four hours. Additionally, the manufacturer reported
several cases where patients who received both drugs died after
developing irreversible hypotension (a severe drop in blood
A Safe Alternative
As safety issues with Viagra began to arise, researchers once
again began to seek out safer alternatives for treating
impotence. Many current pharmaceuticals have evolved from the
historical search for herbal compounds to cure or reverse sexual
dysfunction. Often, traditional nostrums rely on purely magical
(placebo) effects, such as the phallic-influenced belief in the
effect of rhinoceros horn—which, in fact, offers no benefit to
humans and is fatal for the unfortunate rhino. Conversely, many
plant-based traditional treatments, using herbs such as damiana,
maca, muira puama, tribulus, and yohimbe, have been explored for
their effectiveness in treating sexual dysfunction.
Viagra works to increase both the levels and activity of nitric
oxide, leading to increased cGMP, increased blood flow to the
genitals, and more intense sensations. Fortunately, there is a
less expensive way to naturally increase the amount of nitric
oxide released during sexual stimulation. The key is
supplemental L-arginine, the direct precursor of nitric oxide.
In the 1990s, scientists discovered that L-arginine, a
non-essential amino acid commonly found in the diet, is an
oxidative precursor of nitric oxide (NO). As mentioned
previously, nitric oxide is required for achieving and
maintaining penile erection. Under conditions in which nitric
oxide is produced for a specific physiologic purpose, the
concentration of L-arginine (from which it is formed) can be a
Researchers at New York University School of Medicine gave L-arginine
to a group of impotent men, and found that six out of 15 men
receiving the amino acid claimed an improved ability to achieve
erections, while none of the 15 men in the placebo group
reported any benefit.
L-dopa is a chemical precursor of the neurotransmitter dopamine
(which in turn is a precursor of norepinephrine). In other
words, the body uses L-dopa to make dopamine. Several lines of
evidence link activity of dopamine in the brain with sexual
behavior. Generally, it appears that higher levels of dopamine
are associated with more sexual interest and vice versa.
Increased brain dopamine activity caused by taking the drug
L-dopa is believed to be the cause of a hypersexuality syndrome
in people who take the drug for Parkinson's disease.
While L-dopa is available only by prescription, you can increase
your brain dopamine levels by taking the natural herb, Mucuna
pruriens, which is a natural source of L-dopa.
The herb Tribulus terrestris has been used since ancient times
in India as a treatment for both male and female sexual
problems. Tribulus has been widely tested for its efficacy in
enhancing sperm quality and mobility, and for increasing libido
and sexual performance in experimental animals and men. It is
also widely used as a body building substance. Tribulus
administration results in an increase of Luteinizing hormone (LH)
levels by 72%, and free testosterone levels by 41%.
Recently, tribulus has been clinically proven to improve sexual
desire and enhance erection. Researchers at the Surabaya School
of Medicine and Naval Hospital, Indonesia, studied Protodioscin
(PTN), a phytochemical agent isolated from Tribulus terrestris.
They found that tribulus works via the conversion of
protodioscine to DHEA.
Animal studies are beginning to shed light on how tribulus
extracts exert their proerectile effect. Researchers working
with New Zealand white rabbits measured the ability of oral
tribulus to relax corpus cavernosa tissues--necessary for
achieving erections. Their study found that the active
ingredient in tribulus, protodioscin, worked by increasing
corpus tissue responses to acetylcholine, nitroglycerin and
electrical field stimulation. The researchers concluded that the
enhanced erections and aphrodisiac effects observed with
tribulus were due to increases in the release of nitric oxide
(NO) from the endothelium and nitrergic nerve endings.
Muira puama (Ptychopetalum olacoides) is a Brazilian shrub with
a long history in South American folk medicine as an aphrodisiac
and sexual tonic for promoting virility and treating impotence.6
Human studies have substantiated the use of muira puama for
improving libido and treating erectile dysfunction. In one study
conducted at the Institute of Sexology in Paris, France under
the supervision of Dr. Jacques Waynberg, 262 male patients
experiencing lack of sexual desire and the inability to attain
or maintain an erection were treated with 1 to 2.5 grams of
muira puama extract a day. Following two weeks of treatment, 51
percent of those suffering from erectile dysfunction reported
significant improvement. Additionally, 62% of the patients
suffering from loss of libido reported that the muira puama
extract had, in the words of the researchers, a dynamic effect.
A second study conducted by Dr. Waynberg included 100 men who
complained of impotence, loss of libido and sexual difficulties
due to asthenia, described as fatigue, loss of strength, or
debility. Following treatment with Muira puama, 66% of the men
reported a significant increase in frequency of intercourse. Of
46 men complaining of loss of desire, 70% reported that
treatment with muira puama increased libido.
Another important measure of sexual function, stability of
erection during intercourse, was improved or restored in 55% of
the patients. Other benefits reported included a reduction of
fatigue, improved sleep, and increased morning erections.
Treatment with muira puama was much more effective in cases with
the least psychosomatic involvement. Of the 26 men diagnosed
with common sexual asthenia without noticeable sign of
psychosomatic disorder, the treatment was effective for asthenia
in 100% of cases, lack of libido in 85% of cases, and for
inability of coital erection in 90% of cases.
Sexual arousal occurs not just in the genitals but in the whole
body and, especially, in the brain. For men, it actually begins
when the brain sends impulses down the spinal cord and out to
the nerves that serve the penis. These impulses trigger the
production of nitric oxide (NO), which causes penile arteries to
dilate and the spongy core of the penis to relax and become
engorged with blood. The neurotransmitter that carries the
sexual message is acetylcholine (ACh). ACh also seems to control
sexual behavior through its activity in the brain. For women,
ACh is also a very important part of sexual function.
Numerous studies confirm a key role for cholinergic nerve
transmission in sexual responses. Simply speaking, with too
little ACh, sexual activity goes down. Increase ACh levels, and
sexual activity goes up. ACh is involved in the build-up toward
orgasm and the urethral and vaginal contractions that occur
during orgasm as well as the subjective perception of orgasm
intensity and duration.
In addition to its direct role in the sexual response, ACh is
also the primary chemical the body uses to transmit signals from
nerves to skeletal muscles, the muscles that move the body. You
need this chemical for muscular control and proper muscle tone.
There is reason to believe that enhancing cholinergic
neuromuscular transmission will enhance your energy and stamina
by raising your ACh levels and that this can provide indirect
sexual benefits by allowing you to perform longer and with more
While drugs can enhance the body's cholinergic activity, these
drugs not only have unpleasant or even dangerous side effects,
but are available only by prescription. One way to safely and
effectively enhance ACh levels is to take supplements of choline,
along with vitamin B5, so that the body will manufacture more
Vitamin B5, also known as pantothenic acid or calcium
pantothenate, actually seems to enhance endurance by two routes.
The first is its already-mentioned role in creating ACh from
choline. Second, is its role in the energy-producing Krebs'
Cycle, which is vital for all living cells. An early indication
that vitamin B5 might increase physical endurance came from a
study in which rats were placed into a tank filled with cool
(64°F) water and forced to swim until they became exhausted.
Prior to their swim, the rats' diets had included either high,
adequate, or deficient levels of vitamin B5. The high-dose rats
lasted more than four times as long as those whose diet had been
Ginkgo biloba is a highly regarded herb that has been proven to
improve blood flow, enhance oxygenation of tissues, protect
blood vessels from free radical damage, and restore elasticity
and tone to the entire circulatory system. These impressive
properties make ginkgo biloba especially effective for improving
sexual functioning and health in both men and women.
Because circulatory problems are a major factor in impotence,
researchers studied ginkgo to measure its effectiveness for
treating erectile dysfunction caused by impaired blood flow. In
one study, ginkgo was found effective in improving erectile
dysfunction in a group of impotent males taking 60 mg of ginkgo
extract for six months. Researchers suggested that ginkgo worked
by stimulating the release of nitric oxide (NO) which, as
described earlier, signals the blood vessels to dilate and sends
blood to the corpus cavernosum to achieve and maintain an
Ginkgo's positive effects on impotence were further established
by a second study, reported in the Journal of Urology, in which
researchers found that ginkgo was highly effective in helping
men achieve and maintain erections. According to the study
authors, the improvements were due to the direct effect of
ginkgo extract to enhance blood flow in arteries and veins.
Ginkgo as an Aphrodisiac?
Given ginkgo's proven ability to dilate blood vessels and
improve blood flow to the penis, it is not surprising to note
that many aphrodisiac formulas contain ginkgo extract. According
to Dr. Stephen Karch, a specialist in cardiac pathology and
author of The Consumer's Guide to Herbal Medicine, ancient
Chinese herbalists referred to ginkgo as an aphrodisiac. Karch
reports that ginkgo enhances nitric oxide (NO) production.
Nitric oxide is the primary messenger molecule that is affected
by Viagra, and is the key factor in helping achieve erections by
informing certain blood vessels to relax.
Chinese Red Ginseng
In Asia, ginseng has a long history of use in herbal formulas
for the treatment of sexual dysfunction. Recent studies in
laboratory animals have shown that ginseng enhances libido and
sexual performance. These effects of ginseng may not be due to
changes in hormone secretion, but to direct effects of ginseng,
or its ginsenoside components, on the central nervous system and
gonadal tissues. Indeed, there is good evidence that
ginsenosides can facilitate penile erection by directly inducing
the vasodilatation and relaxation of penile corpus cavernosum.
Moreover, the effects of ginseng on the corpus cavernosum appear
to be www.ed by the release and/or modification of release of
nitric oxide from endothelial cells and perivascular nerves.
Ginseng has also been found to affect the central nervous
system, significantly altering the activity of hypothalamic
catecholamines involved in sexual behavior and hormone
secretion. Recent findings that ginseng treatment decreased
prolactin secretion also suggest a direct nitric oxide-www.ed
effect of ginseng on the pituitary. Additional studies lend
growing support for the use of ginseng in the treatment of
sexual dysfunction and provide increasing evidence for a role of
nitric oxide in the mechanism of ginsenoside action.
A healthy sex life contributes to an improved quality of life
and can have profound ramifications on emotional and physical
well being. The compounds discussed here have been shown, singly
and in combination, to be effective in supporting recovery from
source of nutrients and supplements.
did we qualify them ?
1. Panser LA, et al. Sexual function of men ages 40 to 79 years:
the Olmsted County Study of Urinary Symptoms and Health Status
Among Men. J Am Geriatr Soc 1995 Oct;43(10):1107-11
2. Morales A. Yohimbine in erectile dysfunction: the facts.
International Journal of Impotence Research (2000) 12, Suppl 1,
3. Adimoelja A. Phytochemicals and the breakthrough of
traditional herbs in the management of sexual dysfunctions. Int
J Androl 2000;23 Suppl 2:82-4.
4. Adaikan PG, Gauthaman K, Prasad RN, Ng SC. Proerectile
pharmacological effects of Tribulus terrestris extract on the
rabbit corpus cavernosum. Ann Acad Med Singapore 2000
5. Mowrey, Daniel B. Ph.D., 1993. Herbal Tonic Therapies, Keats
6. Duke, James A. 1985. CRC Handbook of Medicinal Herbs, CRC
7. British Herbal Pharmacopoeia, 1983. British Herbal Medicine
Association, West York, England, pp. 132-133.
8. Waynberg, J., Aphrodisiacs: Contribution to the clinical
validation of the traditional use of Ptychopetalum guyanna,
presentation at the First International Congress on
Ethnopharmacology, June 5-9, 1990, Strasbourg, France.
9. Waynberg, J. 1995., Male Sexual Asthenia - Interest in a
Traditional Plant-Derived Medication. Ethnopharmacology, Mar
10. Dini, A., et.al., 1994., Chemical composition of Lepidium
meyenii, Food Chemistry 49: 347-349.
11. Zheng BL, He K, Kim CH, Rogers L, Shao Y, Huang ZY, Lu Y,
Yan SJ, Qien LC, Zheng QY. Effect of a lipidic extract from
lepidium meyenii on sexual behavior in mice and rats. Urology
12. Alarcon-Aguilara FJ, Roman-Ramos R, Perez-Gutierrez S, et
al. Study of the anti-hyperglycemic effect of plants used as
antidiabetics. J Ethnopharmacol 1998 Jun;61(2):101-10.
13. Arletti R, et al. Stimulating property of Turnera diffusa
and Pfaffia paniculata extracts on the sexual-behavior of male
rats. Psychopharmacology (Berl) 1999 Mar;143(1):15-9.
14. Murphy LL, Lee TJ, Ginseng, sex behavior, and nitric oxide.
Ann N Y Acad Sci 2002 May;962:372-7.
15. Jeon BH, Kim CS, Kim HS, Park JB, Nam KY, Chang SJ. Effect
of Korean red ginseng on blood pressure and nitric oxide
production. Acta Pharmacol Sin 2000 Dec;21(12):1095-100.
Brainwave Entrainment Audio Technology
| Advanced Human Biochemical