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White Plains, New York, September 11, 2017 — L-arginine supplements are often promoted to increase exercise endurance, reduce symptoms of congestive heart failure and other cardiovascular conditions, and improve sexual function. But do L-arginine supplements on the market really contain what they claim, and do they really help? To find out, purchased and tested popular L-arginine supplements sold in the U.S., and carefully reviewed the clinical evidence.

The tests revealed that one product contained less arginine than listed on the label. Among products that passed testing, there were significant differences in dose (500 mg to 6,000 mg) and cost (4 cents to 52 cents for an equivalent amount of L-arginine -- 500 mg).

CL's findings are available online in its new L-Arginine Supplements Review, which includes's Top Picks for high quality L-arginine at low cost.

The review includes the clinical evidence for L-arginine supplements and explains the difference between "free form" L-arginine, L-arginine HCl, and L-arginine-alpha-ketoglutarate. It also shows how you can determine how much arginine a product should provide. As not all L-arginine supplements clearly list the amount of arginine they contain on the label, the review explains how to carefully read labels. It also provides the dosage used for specific indications and information about potential side effects and drug interactions with L-arginine.

Included in the review are test results and quality comparisons for 16 supplements, including ten selected for testing by and six that passed the same testing through CL's voluntary Quality Certification Program, plus information about one product that is similar to another that passed testing. Products covered in the review are Daily Wellness ArginMax — Women, Elements of Health Care L-Arginine Plus — Grape, Havasu Nutrition L-Arginine Extra Strength, MuscleTech L-Arginine SX-7 Black Onyx, NOW L- Arginine, L-Arginine, Purethentic Naturals Premium Arginine, Puritan's Pride L-Arginine, Rexall [Dollar General] L- Arginine, Solgar L-Arginine, Spring Valley [Walmart] L- Arginine, Sundown Naturals L-Arginine, Swanson Super Strength L-Arginine, The Vitamin Shoppe L-Arginine, Twinlab L-Arginine, Vitacost L- Arginine HCl, and Vitamin World Maximum Strength L-Arginine.

Founded in 1999, is a leading provider of consumer information and independent evaluations of products that affect health and nutrition. Membership to is available online and provides immediate access to reviews of more than 1,000 products from over 400 brands. The company is privately held and based in Westchester, New York. It has no ownership from, or interest in, companies that manufacture, distribute, or sell consumer products.

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