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ConsumerLab.com Answers
Question: I have low blood pressure. Are there any supplements I should avoid?
Answer: Certain supplements can cause decreases in blood pressure and should be used with caution if you already have low blood pressure. These are melatonin, arginine and large doses of magnesium. Calcium may also cause a very small decrease in blood pressure. Preliminary studies have found black cohosh may lower blood pressure in animals, but it is unclear whether it has this effect in people.
There are also a number of supplements that have been shown to lower blood pressure in people with hypertension (high blood pressure). These include CoQ10, fish oil and omega-3 fatty acids, garlic, potassium, flaxseed, certain strains of probiotics, and green coffee bean extract. While much of the evidence for these is focused on people with high blood pressure, they could potentially lower blood pressure in others. So, if you take one of these supplements and find your low blood pressure becomes even lower, try eliminating the supplement and see if your blood pressure improves.
For more about using these supplements, including the evidence, potential side effects, and our tests of products, use on the links above.
ConsumerLab.com Answers
Question: Is L-arginine helpful or harmful for people with cancer?
Answer: As discussed in our L-Arginine Supplements Review, L-arginine can provide nutritional support and stimulate the immune system in people with cancer who are malnourished. In other people, the level of benefit with arginine seems to depend on the type of cancer: it may help with some, while it may actually promote the growth of others.
For more about this, as well as evidence and safety for other uses of arginine, and our tests of products, see the L-Arginine Supplements Review >>
Question: Which supplements help with erectile dysfunction?
Answer: There is some evidence that arginine, alone or in combination with pine bark extract, may modestly benefit men with erectile dysfunction. Carnitine has been shown in a clinical study to improve erectile function, and, in another study, was shown to increase the effectiveness of sildenafil (Viagra) in men with diabetes who had previously failed to respond to the drug.
The compound yohimbine, from yohimbe bark, is marginally helpful for erectile dysfunction. Yohimbine has been used as prescription drug for this purpose -- although Viagra and related drugs have almost entirely superseded yohimbine for reason of safety and efficacy. Although epimedium (horny goat weed) is commonly promoted for erectile dysfunction, there is little evidence to support this use.
Evidence and dosage for these and other enhancement supplement ingredients, including ginkgo, maca, and deer velvet antler, plus safety concerns and potential drug interactions , and our tests of the quality of popular products, are found in the Review of Sexual Enhancement Supplements >>
Also see the Encyclopedia article about natural approaches to treating Erectile Dysfunction.
Be aware that many sexual enhancement supplements have been found to contain undeclared sildenafil (Viagra), tadalafil (Cialis), and related compounds, which could pose dangers, particularly as the amounts and identities of these compounds are not disclosed on labels (see the list of Warnings for supplements found to contain these drugs).
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Product Review:Review of L-Arginine Supplements
Initial Posting: 8/30/11
L-Arginine Supplements Pass Quality Review But Dosage of Some May Not Be Effective for Expected Use
Find Out Now If Yours Passed!
Alphabetical list of L-arginine supplements in report
BodyTech LongJax MHT with Arginine
Nature's Bounty L-Arginine
Solgar L-Arginine
GNC Pro Performance AMP Amplified N.O. Loaded V2
NSI L-Arginine
Spring Valley L-Arginine
Magna-RX
Puritan's Pride L-Arginine
Sundown Naturals L-Arginine
Natrol L-Arginine
Make sure the L-arginine supplement you take passed our test and is right for you!
Isn't your health worth it?
What is L-arginine? L-arginine (also referred to as just arginine) is an amino acid which may increase blood flow to various parts of the body and be useful in people with congestive heart failure, angina, sexual dysfunction, and other conditions. But do L-arginine supplements help?
ConsumerLab.com purchased, tested and reviewed L-arginine supplements, including those with only L-arginine and those with L-arginine in combination with ingredients such as B-vitamins, epimedium (horny goat weed), LongJax, and Tribulus terrestris.
We found the quality of product to be generally high. However, the suggested dosage of L-arginine for some products may not be effective for their expected use. We also found the cost of L-arginine varied among products, with some offering better value than others.
You must join to get the full test results for L-arginine supplements along with ConsumerLab.com recommendations and quality ratings. You will get results for three supplements selected by ConsumerLab.com and for four others that passed voluntary quality certification testing, as well as information about three supplements similar to ones that passed testing.
You'll get the following information about L-arginine supplements in this comprehensive report:
Which L-arginine supplements passed or failed testing
Direct comparisons and quality ratings of L-arginine supplements
The lowest cost, high-quality L-arginine supplement we found
The dosage of L-arginine shown to work in clinical studies for cardiovascular, sexual enhancement, and athletic uses
Concerns, drug interactions, and potential side-effects of L-arginine supplements
