L-Arginine Supplements Review
Choose the Best
L-Arginine Supplement. Find Out Which L-Arginine Supplement Passed CL's Tests.
Medically reviewed and edited
by Tod Cooperman, M.D. 
Last Updated
: 09/14/2021 | Initially Posted:
08/25/2017Latest Update: Citrulline for Strength?
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Table of Contents
Summary
·
What is L-arginine? L-arginine (or arginine) is an amino
acid which is necessary for the body's production of nitric oxide, a compound
that relaxes blood vessels and allows more blood to flow through arteries. The
form in supplements is typically "free form" arginine, but is
sometimes a compound, such as L-arginine HCl. (See What It Is). Not all labels clearly list the
amount of arginine. (See What to Consider When Buying), but you can use
the Results table to easily compare amounts
of arginine in tested supplements.
·
What are the health benefits of L-arginine? L-arginine may
modestly improve symptoms, such as exercise intolerance, in congestive heart
failure, angina, and leg pain due to intermittent claudication, as well as
exercise endurance in recreational and older athletes. Some, but not all,
studies have shown some modest benefits in sexual dysfunction and Raynaud's
syndrome (See What It Does).
·
How much L-arginine should I take? Dosage depends on
the condition being treated, but is typically several thousand milligrams per
day (See Dosage).
·
Best L-arginine products? Among the products that passed our
laboratory tests (See What CL Found), we selected Top Picks for
arginine for general use, cardiovascular, sexual enhancement, and sport.
·
L-arginine safety and side effects: L-arginine
supplementation appears to be generally safe and well tolerated in healthy
individuals, although stomach upset may occur and capsules have been reported
to irritate the esophagus — so be sure to take with water. L-arginine may
interact with blood-pressure lowering and diabetes medications. Do not use if
you have had a heart attack, and do not use to treat serious conditions
including congestive heart failure, angina, or intermittent claudication
without physician supervision. For details, see Concerns and Cautions.
What It Is:
L-arginine,
also referred to as arginine, is an amino acid required to carry out the
synthesis of nitric oxide, a compound that, working through the compound cGMP,
relaxes blood vessels and allows more blood to flow through arteries. It has
been hypothesized that taking extra arginine will increase nitric oxide levels
and, in turn, increase blood flow to various parts of the body.
What It Does:
Arginine has been clinically studies for a variety of conditions
relating to blood flow, Results have been mixed, and arginine may be less
helpful to people who are well-nourished. Note: The first
three conditions listed below are life-threatening. If you have angina,
congestive heart failure, or intermittent claudication, do not attempt to treat
yourself with arginine except under physician's supervision.
Congestive Heart Failure (fluid build-up in lungs and legs due to heart
weakness)
Several small clinical trials have shown that arginine at doses of 5 grams to
15 grams (1 gram = 1,000 mg) daily may improve symptoms of congestive heart
failure as well as objective measures of heart function (Hambrecht, J Am Coll Cardiol
2000).
Angina (chest pain due to reduce blood flow to heart)
Studies have shown improvement in exercise tolerance, although not heart
function, in people with angina when taking 6 grams per day of arginine. (Bednarz Int J Cardiol 2000).
Another study showed decreased symptoms of angina when 6.6 grams of arginine
was taken daily (from a fortified food bar with vitamins and minerals) (Maxwell,J Am Coll Cardiol 2002).
Intermittent Claudication (leg pain during exercise due to insufficient
blood flow)
A study showed that 2 weeks of treatment with 6.6 grams of arginine daily (from
a fortified food bar with vitamins and minerals) improved walking distance by
66% (Maxwell, Vasc
Med 2000). However, a longer (6-month) and better designed study (Wilson, Circulation 2007) found arginine (3
grams per day) to be less effective than placebo.
Raynaud's phenomenon
Because L-arginine is involved in the synthesis of nitric oxide (a compound
which relaxed blood vessels and allows more blood to flow through them), it is
sometimes promoted for this use. A few case reports (Rembold, Mol Cell Biochem 2003)
and preliminary studies have suggested a benefit in certain people. For
example, one very small study found that a dose of 4 grams of L-arginine taken
twice daily was helpful for Raynaud's phenomenon associated with systemic
sclerosis, but not for primary Raynaud's phenomenon (not caused by another
disease/condition); however, this study did not include a placebo, so it's not
possible to determine whether L-arginine was truly effective (Agostoni, Int J Clin Lab Res 1991). A study
which used the same dose of L-arginine and did include a
placebo found no benefit for primary Raynaud's phenomenon (Khan, Arthritis Rheum 1997).
Sexual Enhancement (See Product Review of Sexual Enhancement Supplements for
more information)
It has been hypothesized that taking high levels of arginine could increase
blood flow to the genitals during arousal by increasing nitric oxide levels.
However, in some pharmaceutical studies leading up to the creation of Viagra,
drugs that increased the levels of nitric oxide in the penis were not found to
be effective; rather, it was found necessary to increase sensitivity to the
rise of nitric oxide. The body may simply accommodate to higher background
levels of nitric oxide.
Nevertheless, arginine might offer modest benefit for sexual dysfunction in
men. A double-blind, placebo controlled trial of 50
men with erectile dysfunction tested arginine at a dose of 5,000 mg per day for
six weeks. About a third of the participants who received arginine showed
improvement. For comparison, 11% of men taking a placebo said they also noticed
an improvement (Chen, BJU Int 1999). Taking arginine (5,000 mg daily) along with the prescription
drug tadalafil (Cialis) (10 mg daily) appeared to significantly enhance the
effect of tadalafil in an 8-week double-blind study among 108 diabetic men in
Egypt. Scores on an international erectile function survey increased by 26%
with two placebo pills, 52% with arginine plus placebo, 63% with tadalafil plus
placebo, and 83% with arginine plus tadalafil. Testosterone levels also
increased significantly more with the combination (144%) than with only
arginine (60%), or tadalafil (93%), although the mechanism is unclear.
Unfortunately, the study did not include any reporting of side effects (El Taieb, J Sex Med 2019).
Although arginine alone has not been studied as a treatment for sexual
dysfunction in women, a small but reasonably good double-blind trial found
evidence for benefit with a combination formula (ArginMax
for Women — tested in this Review) providing a daily dose of 2,500 mg of an
L-arginine "proprietary blend", as well as amounts of Panax
ginseng, Ginkgo biloba extract, damiana, plus numerous vitamins and
minerals. In the four-week, double-blind study, 77 women with decreased libido
were given either the combination product (ArginMax)
or placebo. Over 70% of the women taking ArginMax
reported an increase in sexual desire, compared with over 40% of women taking a
placebo. (The placebo effect is notoriously strong for such conditions. Simply
believing that a pill will increase desire or satisfaction can become a
self-fulfilling prophecy.) Other reported benefits included: relative
satisfaction with sex life (74% vs. 37%), improved frequency of orgasms (47%
vs. 30%), and improved clitoral sensation (53% vs. 35%). No significant side
effects were seen. (Ito, J Sex Marital Ther 2001).
There have been other studies of arginine for sexual dysfunction in women, but
because they were not double-blind, placebo-controlled trials, they are of
little scientific value.
Pressure Ulcers (Bed Sores)
Arginine supplementation has shown possible benefit for treating pressure
ulcers based on studies in which it has been given in combination with other
vitamins/minerals. In a review of 4 randomized trials, it was associated with
improvement in some parameters of healing, although not with a statistically
significant improvement in ulcer size. One study among people who were not
malnourished found no benefit compared to placebo. (Langer, Cochrane Database Syst Rev 2014).
Cancer
In women with breast cancer, 30 grams of L-arginine taken for 3 days prior to
chemotherapy did not improve the response rate to the treatment compared to
women who received a placebo -- although it did improve the response rate in
the subset of women whose tumors were smaller than 6 cm (88% vs 52% with
placebo, respectively) (Heys, Int J Oncol 1998).
The same dose has significantly improved certain immune responses in women with
breast cancer (Brittenden, Surgery
1994) and slowed tumor activity in people with non-cancerous
colorectal tumors and decreased a marker of tumor progression in people with
cancerous colorectal tumors (Ma, Clin Cancer Res 2007).
Be aware that certain types of cancer are especially dependent on arginine to
grow — including melanoma and hepatocellular carcinoma -- and drug treatments
that help to break down and eliminate arginine are being investigated as
treatments (Phillips, Cancer Res Treat 2013). For
people with these types of cancers, arginine supplementation would not seem
advisable.
Exercise Endurance and Recovery
L-arginine may modestly increase exercise endurance in recreational and older
athletes. However, it has not been shown to improve exercise performance or
recovery from resistance exercise in trained athletes or active, young
individuals. For example, a small study in Brazil among healthy, active
young men and women found that a single dose of L-arginine (6 grams L-arginine
dissolved in water) taken one hour before high-intensity resistance exercise
did not decrease muscle fatigue, muscle soreness, blood lactate levels, or
levels of a marker of muscle damage (creatine kinase) compared to placebo (Andrade, Appl Physiol Nutr Metab 2018).
L-arginine is widely promoted as a key ingredient in "nitric oxide"
supplements, which are touted as increasing muscle size, but clinical evidence
does not support this use. (See the Nitric Oxide Supplements Review
Article for more information.)
COVID-19
A small, company-funded study in Italy among 90 men and women hospitalized with
severe COVID-19 pneumonia given an oral dose of 1,660 mg of L-arginine (Bioarginina, Farmaceutici Damor S.p.A.), or placebo, twice daily within 15 days of
symptom onset (average 8 days after symptom onset) in addition to standard care
found that, at 10 days, a greater percentage of patients who received
L-arginine had a reduced need for respiratory support (71.1% of patients given
L-arginine vs 44.4% of those given placebo). In addition, those given
L-arginine had significantly shorter hospital stays (25 vs. 46 days,
respectively) and fewer in this group died (6.3% vs. 20.8%) compared to
placebo. L-arginine did not shorten the average time it took to a achieve a
negative COVID-19 test (RT-PCR for SARS-CoV-2) result, and there was no
significant difference between groups in the percentage of patients with
reduced need for respiratory support at day 20, which the researchers
attributed to the greater number of patients in the L-arginine group who had
already been discharged from the hospital by that time (Fiorentino, EClinicalMedicine
2021).
Citrulline
Citrulline, an amino acid that is converted into
L-arginine in the body, is sometimes added as an ingredient in L-arginine
supplements. However, few studies have shown citrulline supplementation to
improve exercise performance.
In a study of ten healthy, recreationally-active young men who took either
6,000 mg of L-arginine, 6,000 mg of citrulline, or placebo for seven days, both
L-arginine and citrulline caused similar increases in blood levels of arginine,
but only citrulline supplementation improved exercise tolerance (by 12%) and
increased the total amount of work completed (by 7%) during a severe-intensity
cycling exercise test compared to placebo (Bailey, J Appl Physiol 2015).
However, a study of 12 recreationally trained young men and women (average age
24) found that a single dose of 8,000 mg of citrulline malate (L-Citrulline
DL-Malate, Bulk Supplements) -- providing 5,333 mg of citrulline -- mixed
into water and taken one hour before high intensity exercise did not improve
performance or decrease fatigue compared to placebo (Farney, J Strength
Cond Res 2017). Similarly, a small
study among young, healthy men and women in the UK found that an 8,000 mg dose
of citrulline malate taken one hour before resistance exercise did not increase
muscle strength or reduce muscle fatigue and worsened delayed
onset muscle soreness (DOMS) in the three days following exercise compared to
placebo (Chappell, J Int Soc Sports Nutr
2018).
A study of 44
older men and women (average age 65), found that 3,000 mg of citrulline malate
taken daily in addition to regular exercise (a 45-minute combination of
walking, slow running, balance exercises and strength training) for six
weeks slightly improved walking speed, but did not
significantly improve muscle strength or endurance compared to exercise plus
placebo (Caballero-Garcia, Nutrients 2021).
Other Uses
Some evidence suggests that arginine may be helpful in AIDS-related wasting,
colds, necrotizing enterocolitis, intolerance to nitrate medication,
post-surgery recovery and in improving kidney function in kidney transplant
patients treated with cyclosporine. There is also preliminary evidence of a
role for arginine in treating other conditions, including senile dementia,
hypertension, and sickle cell disease.
Quality Concerns and
Tests Performed:
Neither
the Food and Drug Administration (FDA) nor any other federal or state agency
routinely tests supplements for quality prior to sale. In order to help consumers identify products of better quality,
ConsumerLab.com tested L-arginine supplements for the amount of L-arginine
claimed in the product. All supplements sold as tablets were tested to see how
long tablets take to break apart in liquid; if they can't break apart fast
enough, less ingredient may be available for absorption by the body. Products
containing whole herbs and/or 250 mg or more of minerals per daily serving were
also tested for contamination with lead, cadmium and arsenic. See How Products Were Evaluated for more
details.
What CL Found:
All but one of the ten L-arginine-containing supplements that
ConsumerLab.com selected for review passed testing, as did seven supplements
tested through ConsumerLab.com's voluntary Quality Certification Program.
The product that failed to pass testing and was Not Approved, was Purethentic Naturals™ Premium Arginine, which
contains additional ingredients and is promoted for cardiovascular health.
Although it contained a substantial amount of arginine, it came up shorter than
promised, containing only 84.2% of its listed 5,400 mg per scoop.
The products fell into two groups: those with only L-arginine and those with
additional ingredients and marketed for cardiovascular health, sexual
enhancement, or sport. (See the Product Review of Sexual
Enhancement Supplements and the Product Review of Muscle Enhancers for
additional related products and information).
Top Picks:
General L-Arginine Supplements
All of the general L-arginine-only products contained their listed amounts of
L-arginine, but, among them, three products provided arginine at the lowest
cost, making them our Top Picks: PipingRock.com L-Arginine (4
cents per 500 mg capsule), Swanson Super Strength L-Arginine (7
cents per 850 mg vegetarian capsule), and Vitacost
L- Arginine HCl (6.5 cents per 744.2 mg capsule — listed as 900 mg of
L-arginine HCl). For each of these, the cost per 500 mg of L-arginine was
calculated to be just 4 cents.
Note: We included Vitamin Shoppe L-Arginine among the general
arginine supplements, but be aware that it includes 10 mg of vitamin B6,
although the rationale for this is not clear. This amount of vitamin B6 is
several times the adult daily requirement, but is well below the upper
tolerable daily limit of 100 mg.
Cardiovascular Supplements with L-Arginine
It is not uncommon to see general claims of cardiovascular support for arginine
supplements and, as noted above (see What It Does), high doses of arginine may help
people with angina or congestive heart failure. We tested two products
specifically marketed as "Cardio Health Formulas" — both sold as
powders providing about 5 grams of arginine per scoop along with similar mixes
of vitamins and other ingredients, including 1,000 mg of citrulline, an amino
acid which is converted into L-arginine in the body.
As noted earlier, one of these products, Purethentic
Premium Arginine 5400 Pro, failed to provide its full, listed amount of
arginine. The other product, Elements l-arginine Plus, passed our
tests and costs somewhat more ($1.30 per scoop) than Purethentic (92
cents per scoop). However, we have no Top Pick in this
category, as there is no evidence to support these formulas. If you want 5,000
mg of l-arginine, you can get it for much less (around 40 cents) from one of
the general arginine capsules (above) or, as a powder, from the MuscleTech product (below).
Sexual Enhancement Supplements with L-Arginine
ConsumerLab.com tested ArginMax for
Women, which, as noted above (see What It Does), was found to be effective in a
small double-blind clinical study of women with decreased libido. Over 70% of
the women taking ArginMax reported
an increase in sexual desire, compared with over 40% of women taking a placebo.
CL's testing of ArginMax found 2,088
mg of arginine in the daily suggested serving of 6 capsules. While the amount
of arginine was not listed on the label, the amount found is consistent with
the fact that L-arginine is listed as the first ingredient in the 2,700 mg of
"Proprietary Blend" per daily serving of this product. (However, this
is slightly lower than the 2,500 mg of L-arginine proprietary blend reported in
the clinically tested ArginMax. The
reason for this discrepancy, and the potential impact on the product's
efficacy, is not clear). However, based on the fact that the labeling was
truthful and there is some clinical evidence to support its efficacy, ArginMax for Women is a CL Top
Pick for this category. It costs $1.07 per daily serving.
Sport Supplements with L-Arginine
As noted earlier, a large dose of L-arginine (5,000 to 6,000 mg per day)
modestly increased exercise endurance in recreational and older athletes with
poor circulation to the legs, but a better study using 3,000 mg found no
benefit. There is little evidence L-arginine improves exercise endurance or
sports performance in healthy people.
ConsumerLab tested two arginine-containing
supplements claiming to help with sport, both claiming to help with better
muscle "pumps." The two products are quite different: Havasu
Nutrition L-Arginine Extra Strength consists of capsules, each
containing 274.2 mg of arginine along with about 200 mg of citrulline (an amino
acid which is converted into L-arginine in the body and was shown in one study to improve exercise
tolerance) and 50 mg cayenne pepper (Note: studies in animals suggest
capsaicin, found in caynenne pepper, may increase
blood flow and stimulate the release of adrenaline (McCarty, Open Heart 2015); limited studies in
people suggest it may have a thermogenic effect, but there is currently little
evidence that it enhances exercise performance or helps to build muscle (Ludy,
Chem Senses 2012)), and 2 capsules per day are suggested. In
contrast, MuscleTech L-Arginine SX-7
Black Onyx is a sweetened powder which suggests a daily serving of one
scoop, providing a very large dose of arginine: 6,000 mg. Both contained the
arginine they claimed. Although, due to its large dose, MuscleTech is more expensive per day ($1.14)
compared to Havasu (57 cents). However, as a source of arginine, MuscleTech is much less expensive: Each 500 mg
of arginine from MuscleTech costs 10
cents, compared to 52 cents from Havasu, making MuscleTech our Top Pick in
this category. A scoop of MuscleTech also
includes 60 mg of vitamin C — which is the adult daily requirement.
Test Results by Product:
Listed
below are results for eighteen different products containing L-arginine,
grouped as L-arginine only, cardiovascular formulas, sexual enhancement
formulas, and use in sport. Products are shown alphabetically within each
category. ConsumerLab.com selected ten of these products. Eight other products
(indicated with CL flask) were tested at the request of their manufacturers or
distributors through CL's voluntary Quality
Certification Program, and are included for having passed testing.
One additional product similar to another that passed testing but is sold under
a different brand name is included.
Also shown below for each product is the claimed amount L-arginine, serving
size recommended on the label, and ingredient and cost comparisons. Products
listed as "Approved" met their ingredient label claims and ConsumerLab.com's quality criteria (see Passing Score). The full
list of ingredients is available for each product by clicking on the word
"Ingredients" in the first column.
|
RESULTS OF CONSUMERLAB.COM TESTING OF L-ARGININE SUPPLEMENTS |
|||||
|
Product Name, Amount
Listed of L-Arginine per Unit, Serving Size, and Suggested Daily Serving on
Label |
Claimed Amount and
Form of L-Arginine Per Labeled Daily Serving |
--TEST RESULTS-- |
Cost For Daily
Suggested Serving On Label |
||
|
OVERALL RESULTS: |
Contained Labeled
Amount of L-Arginine |
Did Not Exceed
Contamination Limit for Lead, Cadmium and Arsenic1 |
|||
|
|
1,500 mg |
APPROVED |
|
NA |
$0.30 |
|
|
1,000 mg to 3,000 mg |
APPROVED10 |
|
NA |
$0.14-$0.43 |
|
|
2,000 mg |
APPROVED |
|
NA |
$0.24 |
|
|
1,000 mg to 1,500 mg |
APPROVED |
|
NA |
$0.08-$0.12 |
|
|
3,000 mg |
APPROVED |
|
NA |
$0.60 |
|
|
500 mg to 3,000 mg |
APPROVED |
|
NA |
$0.13-$0.78 |
|
|
3,000 mg |
APPROVED |
|
NA |
$0.36 |
|
|
3,000 mg |
APPROVED |
|
NA |
$0.69 |
|
|
850 mg to 1,700 mg |
APPROVED |
|
NA |
$0.07-$0.13 |
|
|
500 mg |
APPROVED |
|
NA |
$0.12 |
|
|
1,488.48 |
APPROVED |
|
NA |
$0.13 |
|
|
500 mg |
APPROVED |
|
NA |
$0.08 |
|
|
6,000 mg |
APPROVED |
|
NA |
$3.00 |
|
Puritan's Pride® L-Arginine 1000 mg (1,000 mg
per capsule; 1 capsule, six times daily) |
Similar to Vitamin World®
Maximum Strength L-Arginine 1000 mg |
$1.44 |
|||
|
|
5,110 mg6 |
APPROVED |
|
NA |
$1.306 |
|
|
5,400 mg6 (free form) |
NOT |
Found only 4,547.9 mg
arginine per daily serving6 (84.2% of listed
amount) |
|
$0.926 |
|
|
Lists L-arginine (no
form or amount noted) as first ingredient in 2,700 mg of Proprietary Blend
per 6 capsules. |
NA7 |
Found 2,088 mg
arginine per daily serving |
|
$1.07 |
|
|
548.3 mg3 |
APPROVED |
|
|
$0.57 |
|
|
6,000 mg |
APPROVED |
|
NA |
$1.14 |
|
|
|||||
|
Unless otherwise noted, information about the products
listed above is based on the samples purchased by ConsumerLab.com (CL) for
this Product Review. Manufacturers may change ingredients and label
information at any time, so be sure to check labels carefully when evaluating
the products you use or buy. If a product's
ingredients differ from what is listed above, it may not necessarily be of
the same quality as what was tested. |
|||||
|
Copyright ConsumerLab.com, LLC, 2017. All rights reserved.
Not to be reproduced, excerpted, or cited in any fashion without the express
written permission of ConsumerLab.com LLC. |
|||||
ConsumerTips™:
What to
Consider When Buying:
L-Arginine in supplements is in the form of L-arginine HCl. The hydrochloride
(HCl) portion makes up about 17% of the weight of this molecule. Some products
include this in the listed amount of L-arginine and some do not. It is
important to know how much of the "free" L-arginine you are getting.
Regardless of what the front label says, if the ingredients list in the
Supplement Facts area on the back label says L-arginine HCl, you need to deduct
17% to determine the amount of actual free L-arginine.
Be aware that L-arginine is a hygroscopic compound, that is, it attracts water.
If sold as uncoated tablets and exposed to humidity, the tablets may become
"crumbly" and fall apart over time. You can avoid this by purchasing
L-arginine as capsules (like many of those in this review) rather than as a
tablet. If you purchase a tablet, keep it out of humidity and keep a desiccant
packet in the closed bottle.
What to Consider When Using:
In studies of arginine, the following dosages have been used with some success
for the following indications:
·
Congestive heart failure: 5 to 15 grams daily
·
Angina: 6 to 6.6 grams daily
·
Intermittent claudication: 6.6 grams daily (short-term only).
May not be effective long-term.
·
Sexual dysfunction in women: 2,500 to 6,000 mg daily
·
Sexual dysfunction in men: 5,000 mg daily may be effective,
while 1,500 mg daily is not. Results may take up to four weeks.
·
Athletic training: 5,000 to 6,000 mg per day may be effective in
recreational athletes (See NO2 article).
Concerns and Cautions:
In
clinical trials, use of oral arginine in healthy individuals has not been
associated with any serious adverse effects, other than occasional mild
stomach upset.
Several cases of esophagitis (inflammation of the esophagus)
have been reported with l-arginine capsules, including a report in Canada of a
40-year old woman who ingested two large 500 mg capsules of L-arginine (Now
Supplements, Guelph, Ontario) before going to bed (O'Donnell, ACG Case Rep J, 2019). [Note: The
report stated the pills to be tablets but they were actually capsules,
according to correspondence by CL with the researchers on 10/18/19]. It is
advisable that all pills, particularly capsules, be taken with copious amounts
of fluid, including before swallowing the pill. It is also advisable not to
take pills while, or just before, lying down, so that gravity can facilitate
passage.
It has been suggested (but not proven) that high dose oral arginine may
increase stomach acid levels and worsen esophageal reflux (heartburn).
For this reason, individuals with ulcers or esophageal reflux should use
caution when taking arginine. In addition, individuals taking medications that
irritate the stomach, such as NSAID drugs (medications in the aspirin/ibuprofen
family) might increase their risk of developing ulcers if they take arginine as
well.
Arginine may improve the body's ability to respond to insulin. This could be a
benefit, but it could cause problems in individuals taking medications
for diabetes.
Arginine should not be recommended for people who have had an acute
myocardial infarction because a study showed an increase in deaths in
such people taking arginine versus those who took placebo.
Arginine may cause a mild reduction in blood pressure, but studies
have not shown a consistent effect. Use arginine cautiously with medicines or
supplements that may lower blood pressure.
Arginine has been shown to induce acute pancreatitis in mice
and there have been two reports of acute pancreatitis in
individuals taking moderate doses of arginine. One was a 16-year
old boy in Turkey taking 500 mg of arginine daily (and 10 mg of zinc,
which can enhance the effect of arginine) daily for more than 5 months when he
developed abdominal pain with a serum amylase rising to 310 U/L (normal range
is 25-90 U/L). The other was a 28-year old man in
Belgium who, for 18 months, had taken a protein powder formula containing 1,200
mg of arginine when he developed epigastric pain and loss of appetite. His
serum lipase level was 1,393 U/L (normal is under 60 U/L). (Lipase and amylase
are pancreatic enzymes that are elevated in pancreatitis.) Other possible
causes of acute pancreatitis were ruled out, and after 3 days of intravenous
hydration and nothing by mouth, he was discharged from the hospital. He was
instructed to quit arginine and, at 6-month follow up, had suffered no
recurrence and serum lipase was normal (Binet, Clin J Gastoenterol 2018).
Citrulline:
In clinical trials lasting from one week to several months, daily doses of
citrulline up to about 10 grams per day have generally been safe and
well-tolerated, although occasionally, side effects such as gastrointestinal
upset, and heartburn have been reported — although citrulline supplementation
appears to be less likely to cause gastrointestinal upset than arginine
supplementation. Increased urinary frequency, cough and swelling of arms and legs
with citrulline supplementation has been reported in people with arterial
pulmonary hypertension (Allerton, Nutrients 2018; Kashani, J Cardiol 2014).
Because citrulline is converted to arginine in the body, it might, like
arginine, potentially reduce blood pressure, so it should be used with caution
in people taking blood pressure lowering medications, nitroglycerine or other
medications containing nitrates, and erectile dysfunction/phosphodiesterase-5
(PDE-5) inhibitors drugs such as sildenafil (Viagra) and tadalafil (Cialis).
Certain urea cycle disorders, such as argininosuccinate
synthetase deficiency are associated with elevated blood levels of citrulline;
it's possible that citrulline supplementation could affect tests used to detect
and/or monitor these disorders (Berry,
J Pediatr 2001).
Information on this site
is provided for informational purposes only. It is not an endorsement of any
product nor is it meant to substitute for the advice provided by physicians or
other healthcare professionals. The information contained herein should not be
used for diagnosing or treating a health problem or disease. Consumers should
inform their healthcare providers of the dietary supplements they take.
Latest Clinical Research Updates for L-Arginine Supplements
9/14/2021
Find out if citrulline
supplementation improved muscle strength or endurance in older people in
recent study. (This information is in the Citrulline section of our L-Arginine
Supplements Review, as citrulline is converted to arginine in the body and it
is often sold in combination with arginine).
9/14/2021
Did L-arginine
supplementation help people with severe COVID-related pneumonia? See what a new
study found in the What It Does section of our L-Arginine
Supplements Review.
Also see: Do any supplements help with the coronavirus (COVID-19)?
10/19/2019
Several cases of
esophagitis have been reported from taking supplements, including a recent case
involving l-arginine capsules. For details, including tips on how to safely
take pills, see the Concerns and Cautions section
of the L-Arginine Supplements Review. Also see our Top Picks for
L-Arginine.
7/23/2019
Does daily arginine
supplementation enhance the effect of a popular prescription medication for
men? See what a recent study found in the What It Does section
of the L-Arginine Supplements Review. Also see our Top Picks for
arginine.
8/14/2018
Several studies have
evaluated citrulline (which the body converts to arginine) for enhancing
athletic performance. Find out if it helps or not in the Citrulline section
of the L-Arginine Review. Also, find out if L-arginine, itself, can
help.