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White Plains, New York, March 15, 2017 — Many people take large doses of vitamin C believing it will improve their health, prevent colds or reduce the risk of disease — but will it really? And when choosing a vitamin C supplement, can consumers be sure it contains what it claims? To find out, recently reviewed the clinical evidence and tested popular vitamin C supplements sold in the U.S. and Canada.

The tests revealed that three out of 15 popular supplements contained much more vitamin C than listed. This is of concern because taking amounts of vitamin C above the Tolerable Upper Intake Level (UL) increases the risk of adverse effects from the vitamin. also found the cost of obtaining an equivalent dose of vitamin C from the products varied significantly, from just 1 cent to $2.80. Among products which were approved, it identified several as Top Picks — some of which cost only pennies per day.

It is easy to get the daily requirement of vitamin C from fruits and vegetables; however, many people believe it is beneficial to take doses of vitamin C that are many times the daily requirement. points out that mega-doses of vitamin C provide few and modest potential benefits, which may be outweighed by side-effects such as diarrhea and, with long-term use, increased risk of cataracts and kidney stones. Even taking high-dose vitamin C during cold season may only slightly reduce the risk of getting a cold and, unless you are deficient, vitamin C won't help at all if you start taking it after you become sick.

The results are available online now in's Vitamin C Supplements Review ( The report also summarizes the clinical evidence for vitamin C, dosage, the different forms of vitamin C (Ester-C, sodium ascorbate, slow-release vitamin C, and liposomal vitamin C), side-effects, and potential drug interactions.

Test results and quality comparisons are included for the following products 29 products, 15 which were selected for testing by and 14 which are included for having passed the same testing through CL's voluntary Quality Certification Program: American Health Ester-C, Bronson Laboratories Vitamin C Crystals, CVS Pharmacy C, Dynamic Health Liquid Vitamin C for Kids - Natural Citrus Flavors, Emergen-C, Garden of Life Mykind Organics Vitamin C, Jamieson C, Kirkland Signature (Costco) Vitamin C, Life Extension Vitamin C with Dihydroquercetin, LivOn Laboratories Lypo-Spheric Vitamin C, Metagenics Ultra Potent-C, Nature Made C, Nature's Bounty C 1,000 mg, Nature's Plus Vitamin C, Vitamin C, Rainbow Light Gummy Vitamin C Slices, Rexall Vitamin C, Shaklee Vita -C, Spring Valley [Walmart] C, Sundown Naturals Vitamin C, The Vitamin Shoppe Vitamin C 1,000 mg — Capsule, The Vitamin Shoppe Vitamin C 1,000 mg — Softgels, TwinLab C-1000 Caps, Up & Up [Target] Vitamin C, Vitacost Vitamin C, Vitafusion L'il Critters Immune C Plus Zinc & Echinacea, Vitafusion Power C, Vitamin World C-1,000 mg and Well at Walgreens Vitamin C With Natural Rose Hips.

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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