Arginine or L-Arginine is an amino acid involved in numerous
areas of human biochemistry, including ammonia detoxification, hormone
secretion, and the immune system. Arginine is also well known as a precursor to
nitric oxide, a key component of endothelial-derived relaxing factor. The
endothelium is the lining inside blood vessels and arginine supplements help
make more nitric oxide. Therefore arginine, by making more nitric oxide, helps to relax and
dilate blood vessels. Nitric oxide is a messenger molecule involved in a variety of endothelium-dependent
effects in the cardiovascular system. Because of arginine's nitric
oxide-stimulating effects, there have been claims that this amino acid is useful in hypertension, preeclampsia, intermittent claudication, and erectile dysfunction.
Arginine has been studied for its role in athletic performance,
burns and trauma, diabetes and syndrome X, male and female infertility, and
interstitial cystitis. What does the research say about the benefit of arginine
supplements for various medical conditions?
Even though arginine supplements have been
claimed to be useful for
some of the conditions listed above, it would be premature to be overly excited.
Much research needs to be done before we
can be more confident about the health benefits of arginine supplements. However,
thus far, arginine amino acid
appears to have a role to play in conditions involving blood vessel dilation.
Whether the dilation is short lived or continues for an adequate period is still
being evaluated. Arginine does not appear to be helpful as a supplement taken by
those who have suffered a heart attack. However, some research supports the use
of arginine in heart failure.
L Arginine supplement 750 mg, 60 Capsules
L Arginine is a semi-essential amino acid synthesized by the body from ornithine. Arginine supports protein synthesis as it is involved in the transport and
storage of nitrogen. Among many functions, L Arginine amino acid is used by the body to produce creatine. Each arginine supplement
capsule contains 750
mg elemental L Arginine.
Usage: Take 1 to 6 arginine supplement capsules daily, or as directed by your qualified health consultant.
L Arginine supplement 750 mg, 60 Capsules
L Arginine is a semi-essential amino acid synthesized by the body from ornithine. Arginine supports protein synthesis as it is involved in the transport and
storage of nitrogen. Among many functions, L Arginine is used by the body to produce creatine. Each arginine supplement
capsule contains 750
mg elemental L Arginine.
Usage: Take 1 to 6 arginine supplement capsules daily, or as directed by your qualified health consultant.
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L Arginine amino acid and erectile dysfunction
studies
One of the more popular supplements for sexual
dysfunction is L-arginine, also referred to as arginine. Arginine is a versatile amino
acid in animal cells, serving as a precursor for the making not only of proteins but also
of nitric oxide, urea, glutamate, and creatine. What makes l-arginine
interesting is that it can
be metabolized to nitric oxide (NO). NO is the most powerful chemical known to dilate and
engorge blood vessels in the penis and clitoris. What does the research say
about the role of arginine in erectile dysfunction?
A
Low dose of l arginine amino acid supplement, at 500 mg three times a day,
was not found to be
effective for erectile dysfunction.
A double-blind, placebo-controlled study of 50 men with erectile
dysfunction tested l arginine at a dose of 5 grams per day for six weeks. About a
third of the participants who received l arginine showed improvement, and that
improvement was greater than the 10% improvement seen in the placebo group.
The amino acid L arginine has been studied in combination with other nutrients as a treatment for sexual dysfunction in women. A small trial found some improvement with a combination treatment providing a daily dose of 2,500 mg of l arginine, as well as ginseng, ginkgo, and damiana. In a four-week, double-blind study, 77 women with decreased libido were given either the combination product or a placebo. Those taking the arginine blend showed statistically greater improvement, reporting increased sexual desire in 71% of participants given the treatment. In the placebo group, 42% reported an increased libido. Other improvements included relative satisfaction with sex life and heightened clitoral sensation. No significant side effects were seen in either group. However, we don't know if the arginine had anything to do with the results.
A study done at the University of Texas at Austin examined l arginine benefit, combined with yohimbine, on sexual arousal in postmenopausal women. Twenty-four women participated in three sessions in which sexual responses to erotic stimuli were measured following treatment with either arginine glutamate (6 grams) plus yohimbine (6 mg), yohimbine alone (6 mg), or a placebo. Sexual responses were measured at one hour after taking the supplements. Compared to placebo, the combined oral administration of arginine and yohimbine substantially increased vaginal pulse amplitude responses to the erotic film. It is well known that yohimbine, alone, has a significant effect on sexuality and whether arginine was a factor is not known.
Mechanism of action of the amino acid L Arginine
The most likely explanation for the mild effectiveness of l arginine amino acid is its
conversion into nitric oxide. Nitric oxide is
converted into cGMP, which becomes the secondary messenger that causes smooth
muscle relaxation, resulting in blood vessel dilation, and more blood going into the genital organs, which
leads to erections. However, nitric oxide is quickly metabolized and any
potential l arginine benefit could be short lived.
L Arginine
benefits
There is some supporting evidence that l arginine offers benefits in reducing
angina and lowering blood pressure (see studies bottom of page). Research
indicates supplemental l arginine reduces pulmonary resistance and blood pressure. Arginine supplementation improves renal function in patients with chronic heart
failure.
Polish researchers have found that arginine supplements increases exercise
tolerance in stable coronary artery disease patients.
Oral L-arginine improves endothelial function in
older healthy individuals. However, I am not convinced yet that arginine is a
worthwhile supplement for erectile function or sexual enhancement, at least when
used in
low dosages.
L arginine and cancer
L-arginine reduces cell proliferation and ornithine decarboxylase activity in
patients with colorectal adenoma and adenocarcinoma.
Clin Cancer Res. 2007 December. Departments of General Surgery, The First
Hospital of Xi'an Jiaotong University, Xi'an, PR China.
Evidence suggests that the majority of colorectal carcinomas arise from
adenomas, and L-arginine suppresses colorectal tumorigenesis. We suppose that L-arginine
may inhibit the process of carcinogenesis from colorectal adenoma to
adenocarcinoma. The aim of this study was to investigate the effects of L-arginine
on the formation and development of colorectal tumors. We selected 60 patients
with colorectal cancer and 60 patients with colorectal adenoma (CRA) and divided
them into four groups of 30 patients each. We gave 30 g (120 mL) of L-arginine
everyday for 3 days to the test groups, whereas L-arginine was substituted by 5%
glucose in the control groups. The expression of the proliferating cell nuclear
antigen, survivin, and nitric oxide synthase was examined immunohistochemically,
and ornithine decarboxylase (ODC) activity was examined spectrophotometrically.
Serum nitric oxide (NO) was detected by the Griess assay. In patients with CRA,
the proliferating cell nuclear antigen and survivin labeling indexes and ODC
activity of the tumor and paratumor mucosa in the L-arginine-treated group after
L-arginine treatment were significantly lower as compared with the corresponding
pretreatment values (P < 0.01). Moreover, inducible nitric oxide synthase
expression in the tumor markedly increased after L-arginine treatment (P <
0.05). Serum NO levels in the patients with colorectal cancer were markedly
higher than those in the patients with CRA, and L-arginine treatment was
responsible for this increase. Our results show that L-arginine can restrain
crypt cell hyperproliferation and the expression of survivin, an inhibitor of
apoptosis protein. This suggests that L-arginine can block the formation and
development of colorectal tumors, and this effect might be related to the
increased serum NO concentration and decreased ODC activity.
Benefit of arginine for heart failure
L-arginine supplements may improve the
physical fitness of heart failure patients by enhancing their endurance to
exercise. Dr. Stephane Doutreleau and colleagues from Institut de Physiologie,
Strasbourg, France, examined the potential benefits of 6 weeks of L-arginine
supplements on endurance exercise in 10 patients with chronic stable heart
failure. Patients who took L-arginine
experienced a significant decrease in their average heart rate throughout
exercise and the recovery period. There were no significant changes in blood
pressure and respiratory parameters. The current study supports a prior study in
which a group of heart failure patients were shown to benefit from a combination
of exercise and L-arginine supplements. In that study, the combination appeared
to help correct the abnormal functioning of blood vessels seen in chronic heart
failure. International Journal of Sports Medicine July 2006.
L arginine not helpful in
peripheral artery disease
L-arginine supplementation in peripheral arterial disease: no benefit and
possible harm.
Circulation. 2007 July 10. Wilson AM, Harada R, Nair N, Balasubramanian
N, Cooke JP. Division of Cardiovascular Medicine, Stanford University School of
Medicine, Stanford, California.
L-arginine is the precursor of endothelium-derived nitric oxide, an endogenous
vasodilator. L-arginine supplements improve vascular reactivity and functional
capacity in peripheral arterial disease (PAD) in small, short-term studies. We
aimed to determine the effects of long-term administration of L-arginine on
vascular reactivity and functional capacity in patients with PAD. The Nitric
Oxide in Peripheral Arterial Insufficiency (NO-PAIN) study was a randomized
clinical trial of oral L-arginine (3 grams a day) versus placebo for 6 months in
133 subjects with intermittent claudication due to PAD in a single-center
setting. In patients with peripheral artery disease, long-term administration of
L-arginine does not increase nitric oxide synthesis or improve vascular
reactivity.
Benefit of L arginine
supplements in gestational hypertension
L-arginine supplementation in patients with gestational hypertension: a pilot
study.
Hypertens Pregnancy. 2007. Mother-Infant Dept., Section of Gynaecology
and Obstetrics, University of Modena and Reggio Emilia, Italy.
Patients with gestational hypertension and proteinuria and those without
proteinuria were randomized in a double-blind design to receive either L
arginine (20 grams / 500 mL intravenously daily, for 5 days followed by 4 grams
/day orally for 2 weeks) or placebo. Compared with baseline, both systolic and
diastolic blood pressue 6 days after treatment were significantly reduced in the
l arginine group but not in the placebo group. The treatment with l arginine
seems promising in prolonging pregnancy and reducing blood pressure,
particularly in patients with gestational hypertension and without proteinuria.
L arginine and heart attack
Q. I came across a web site where it says not to take l arginine supplements
following a heart attack (does that apply to recent and old one?) and that six
people had died during an arginine study. I am 66 and have had a heart attack in
1989 and don’t take any drugs for it. I wanted to try an arginine supplement
because of the benefits I have read about, especially erectile dysfunction, and
better circulation, but am now afraid to do so.
A. I have listed the arginine heart attack study below. It would
seem prudent to not use l arginine supplements the first few months after a
heart attack. However, at least one or two additional studies are needed to
determine whether the results of this study regarding the influence of l
arginine supplements and heart attack were coincidence or whether l arginine
does have a negative impact on heart health in those who have had a recent heart
attack.
L-arginine therapy in acute myocardial infarction:
the Vascular Interaction With Age in Myocardial Infarction (VINTAGE MI)
randomized clinical trial.
JAMA. 2006 Jan 4. Schulman SP, Becker LC, Kass DA, Champion HC, Terrin
ML, Forman S, Ernst KV, Kelemen MD, Townsend SN, Capriotti A, Hare JM,
Gerstenblith G. Division of Cardiology, Johns Hopkins Medical Institutions,
Baltimore, USA.
To determine whether the addition of L-arginine to standard postinfarction
therapy reduces vascular stiffness and improves ejection fraction over 6-month
follow-up in patients following acute ST-segment elevation myocardial
infarction. A total of 153 patients following a first ST-segment elevation
myocardial infarction were enrolled; 77 patients were 60 years or older.
Patients were randomly assigned to receive L-arginine (goal dose of 3 g 3 times
a day) or matching placebo for 6 months. Baseline characteristics, vascular
stiffness measurements, and left ventricular function were similar between
participants randomized to receive placebo or L-arginine. There was no
significant change from baseline to 6 months in the vascular stiffness
measurements or left ventricular ejection fraction in either of the 2 groups,
including those 60 years or older and the entire study group. However, 6
participants (8.6%) in the L-arginine group died during the 6-month study period
vs none in the placebo group. Because of the safety concerns, the data and
safety monitoring committee closed enrollment. L-arginine, when added to
standard postinfarction therapies, does not improve vascular stiffness
measurements or ejection fraction and may be associated with higher
postinfarction mortality.
L Arginine dosage
L Arginine is available most often as 750 to 1,000 mg capsules and in powder
form. The dosage of l arginine depends on the condition being treated. In some
cases, an arginine dosage of more than 5 grams a day may be required.
History of L arginine amino acid
L arginine was first isolated in 1886. In 1932, L arginine was found to
be required for the generation of urea, which is necessary for the removal of
toxic ammonia from the body. In 1939 L arginine was also shown to be required
for the synthesis of creatine, the muscle builder.
Arginine deficiency
Symptoms of arginine deficiency include poor wound healing, hair loss,
skin rash, constipation, and fatty liver. Arginine is considered a
semi-essential amino acid, because although it is normally synthesized in
sufficient amounts by the body, arginine supplementation is sometimes required
(for example, due to inborn errors of urea synthesis, protein malnutrition,
excessive lysine intake, burns, peritoneal dialysis, and rapid growth).
L Arginine side effects
I have not come across any significant l arginine side effects up to now.
It is possible that one side effect of high dosage l arginine is nausea. Other
possible l arginine side effects on very high dosages are digestive
disturbances. I have personally taken more than 10 grams l arginine at one time
at least on three different occasions without any significant side effects. But,
it is not clear whether l arginine has side effects if used in high dosages
daily for
many months or years.
L Arginine and nitric oxide
Arginine is a precursor of nitric oxide, which causes blood vessel
relaxation. Although there is some evidence that suggests that arginine
supplements may be
useful in the treatment of medical conditions that are improved by vasodilation,
such as angina, atherosclerosis, coronary artery disease, erectile dysfunction,
heart failure, intermittent claudication / peripheral vascular disease, and
vascular headache, more proof is needed. The appropriate l arginine dosage and long term
safety is not clear at this time. Arginine also stimulates protein synthesis and
has been studied for wound healing, bodybuilding, enhancement of sperm
production (spermatogenesis), and prevention of wasting in people with critical
illness.
Arginine benefit for sexual enhancement
There are many potent herbs that have sexual enhancement properties.
Arginine is not on my top ten list of aphrodisiac supplements and I don't think
a
l arginine health benefit is significant erection enhancement. I prefer the
sex enhancing herbs found in Passion Rx which are much more potent and effective.
Arginine side effects
No major l arginine side effects have been reported in the medical
literature. It is unlikely that dosages of arginine supplements less
than 3 grams a day would lead to any significant side effects.
Arginine metabolism by the kidneys
The kidney plays a major role in arginine metabolism in 3 principal ways:
arginine synthesis, creatine synthesis, and arginine reabsorption. Arginine is
made in the kidney from citrulline produced by the intestine. The renal enzymes
of arginine synthesis, argininosuccinate synthetase and argininosuccinate lyase,
occur in the cells of the proximal tubule. The rate of arginine synthesis
depends on citrulline delivery and does not appear to be regulated by dietary
arginine availability. Renal arginine synthesis in humans produces approximately
2 grams arginine per day, which may be compared to an intake, from a Western diet, of
approximately 4 to 5 grams a day. Spontaneous, nonenzymatic breakdown of creatine and
creatine phosphate to creatinine causes the excretion of 1 to 2 g creatinine a
day
and requires the replacement of an equivalent amount of creatine from the diet
and by endogenous synthesis. The first enzyme of creatine biosynthesis, L-arginine:glycine
amidinotransferase, occurs in the kidney and produces guanidinoacetate, which is
released into the renal vein. The renal output of guanidinoacetate, however, is
rather low, and we propose that the entire pathway of creatine synthesis may
also occur in the liver. Renal arginine reabsorption salvages approximately 3 grams
of arginine per day. At the apical membrane of proximal tubular cells, arginine shares a
transporter with lysine, ornithine, and cystine. Defects in this heteromeric
transporter cause cystinuria, which is also characterized by urinary loss of
arginine, lysine, and ornithine.
L Arginine research update
L-Arginine supplement improves vascular function by overcoming deleterious effects
of ADMA, a novel cardiovascular risk factor.
Altern Med Rev. 2005 Mar;10(1):14-23.
There is abundant evidence that the endothelium plays a crucial role in
the maintenance of vascular tone and structure. One of the major
endothelium-derived vasoactive mediators is nitric oxide (NO), an endogenous
messenger molecule formed in healthy vascular endothelium from the amino acid
precursor L-arginine. Endothelial dysfunction is caused by various
cardiovascular risk factors, metabolic diseases, and systemic or local
inflammation. One mechanism that explains the occurrence of endothelial
dysfunction is the presence of elevated blood levels of asymmetric
dimethylarginine (ADMA) -- an L arginine analogue that inhibits nitric oxide formation and
thereby can impair vascular function. Supplementation with L-arginine has been
shown to restore vascular function and to improve the clinical symptoms of
various diseases associated with vascular dysfunction
Plasma l arginine concentrations are reduced in cancer patients: evidence
for arginine deficiency?
American Journal of Clinical Nutrition, Vol. 81, No. 5, 1142-1146, May
2005
Preliminary evidence suggests that arginine availability in cancer is reduced.
However, no valid data are available on plasma arginine concentrations in cancer
patients. We aimed to determine whether there is evidence for
disturbed arginine metabolism in cancer. We measured plasma arginine
concentrations postabsorptively in patients with various types of tumors,
hypothesizing that arginine concentrations would be lower than those in age- and
sex-matched control subjects. Patients with localized tumors with a range of
metabolic implications were studied: breast cancer (no weight loss), colonic
cancer (sometimes weight loss), and pancreatic cancer (usually weight loss). Plasma arginine
concentrations were lower in patients with cancer irrespective of tumor type,
weight loss, tumor stage, or body mass index.
Malignant tumors associated with various degrees of metabolic
derangements are all associated with decreased plasma arginine concentrations,
even without weight loss. This suggests that decreased arginine availability is
a specific feature of the presence of cancer. These disturbances in arginine
metabolism could contribute to the cascade of metabolic events leading to cancer
cachexia.
Types of arginine supplements
available over the counter
L-Arginine Alpha Keto Glutarate
is a form of arginine amino acid supplement promoted to enhance nitric oxide
production.
N-Hydroxy-Arginine is a form of arginine
amino acid
supplement. Arginine plays a role in the urea cycle, helping to rid the body of
excess ammonia.
Arginine emails
Q. Should a l arginine amino acid supplement be taken with meals or on an empty stomach?
A. L Arginine amino acid supplements are probably more effective when taken on an empty stomach.
Q. Can I take l arginine regularly for many months?
A. As with most nutrients, I recommend taking breaks from use. In the case of
arginine, it appears to be safe to take for extended periods as long as the dose
is less than 2 grams a day.
Q. Is l arginine better to take as a capsule or powder?
A. It depends on how much you plan to take. If your dose is 1 to 5 g, the capsule
works. If you plan to take more than 5 grams of arginine, then the powder is more efficient.