Search term may appear only in full report available to members. Join now for full access.

News Release

April 24, 2025

ConsumerLab Tests Identify Best Glycine Supplements

White Plains, NY, April 24, 2025 —  Glycine supplements are promoted to improve sleep and mood, reduce symptoms of overactive bladder and chronic prostatitis, and for other benefits, but do they really work, and if so, which glycine products on the market are best?

Product Review

Olive Leaf Extract Supplements Review

Learn What Olive Leaf Does and the Best Brands

Product Review

Lion's Mane and Chaga Supplements Review

Read Labels Carefully -- Many Can Mislead

Product Review

Lavender and Tea Tree Essential Oils Review

Oils Tested for Authenticity and Purity

Product Review

Electrolytes & Sports Drinks Review

See Which Sports Drinks, Powders, and Pills Deliver the Right Electrolytes

Product Review

Protein Powders, Shakes, and Meal Replacements Review

Find Out Which Protein Products Passed or Failed Our Tests

CL Answer

Sugar Substitutes: Pros, Cons, and Best Choices

Learn about the pros and cons of using sugar substitutes and artificial sweeteners in place of table sugar. Sweeteners discussed include stevia, monk fruit, and other high-intensity sweeteners; xylitol, erythritol, allulose and other low-calorie sweeteners; and agave syrup, black sugar, coconut sugar, honey, molasses and other sugar alternatives.

CL Answer

Which supplements and lifestyle changes improve sleep, and which cause insomnia?

Find out which vitamins may help you sleep and learn if any vitamins or supplements can cause insomnia.

Product Review

NAC (N-Acetyl Cysteine) Supplements Review

Choose the Best N-Acetyl Cysteine Supplement. See Our Tests of Popular NAC Supplements and Top Picks for Quality and Value.

Product Review

GABA Supplements Review

Does GABA Work As a Supplement?

CL Answer

AGZ for Sleep – Is It Worth It?

AGZ claims to "support restful, restorative sleep" without melatonin, but is there evidence to support this use and is it worth its price? Find out.

CL Answer

10 Supplements That May Help Reduce Nighttime Urination (And 5 That May Not)

Waking up more than once during the night to use the bathroom? Learn more about the 9 supplements that may help and 5 others that don't.

CL Answer

Are supplements with amino acid chelated minerals better than those with other forms of minerals?

Learn more about chelates, including evidence from clinical studies on selenium, iron, and magnesium.

Product Review

Zinc Supplements, Lozenges, and Melts Review

Find the Best Zinc Supplements, Including Lozenges for Colds.

Product Review

Collagen Supplements Review

See our Top Picks for Wrinkles and Joints

Product Review

Prostate Supplements Review (Saw Palmetto and Beta-Sitosterol)

Find the Best Prostate Supplement for Symptoms of BPH. See Which Prostate Supplement Passed or Failed CL's Tests of Quality.

Product Review

Joint Health Supplements Review (Glucosamine, Chondroitin, MSM, Boswellia, Collagen and Turmeric)

18% of Joint Health Supplements Failed to Pass Our Tests. See Which Passed or Failed, and Our Top Picks.

CL Answer

Here’s What You Should Look For In Toothpaste and Mouthwash, and Our Top Picks

Learn about ingredients you want in your toothpaste, mouthwash and other dental products and which ingredients you may want to avoid.

CL Answer

If I buy NAC as a loose powder in a large bag, as opposed to in tablet or capsule form, will it spoil? I've heard it can spoil or degrade into a harmful by-product.

Learn more about the different forms of N-Acetyl-Cysteine (NAC), including whether or not powder will spoil faster than tablets.

Product Review

Magnesium Supplements Review (Including Calcium, Vitamins D & K, and Boron)

Find Out What Magnesium Does, Who Needs It, and Our Top Picks Among Supplements

Product Review

L-Lysine Supplements Review

Read L-Lysine Labels Carefully. Some Can Fool You.

Product Review

Glutathione Supplements Review

Learn How Glutathione Products Differ, Which Failed, and Our Top Picks

CL Answer

Where to Safely Buy Real Vitamins and Supplements Online, Not Fakes or Counterfeits

ConsumerLab explains how to avoid counterfeit vitamins and supplements when shopping online on Amazon, Walmart.com, and other sites. Learn to identify authorized sites and sellers and avoid fake supplements. Use the brand-by-brand guide to protect yourself from risk.

CL Answer

Risks of Too Many Vitamins & Supplements

Taking too many vitamin supplements -- or taking too much of a particular supplement -- can have short and long-term adverse effects.

CL Answer

Do any supplements help relieve stress?

Are there actually supplements for stress relief and panic attacks? Learn more about holy basil, fish oil, L-theanine, and ginseng.

CL Answer

Which supplements, foods or diet and lifestyle changes help relieve acid reflux (heartburn), and which worsen it?

Find out which supplements and foods can help relieve acid reflux, and which can make it worse.

CL Answer

Do any supplements or lifestyle changes reduce the symptoms of tinnitus? Is it true that some supplements can cause tinnitus?

Learn which supplements can ease tinnitus, including melatonin and pine bark extract. Understand which may actually cause tinnitus.

CL Answer

Do any supplements help with COVID-19? Do supplements like vitamin D, zinc, vitamin C, or herbals work?

Find out if natural remedies & supplements for coronavirus such as zinc, vitamin C, garlic, or elderberry help to prevent or treat COVID-19.

CL Answer

L-Serine & D-Serine: Health Benefits and Safety

Serine exists in two forms: L-serine and D-serine. Find out how these two forms differ and learn if either form has health benefits and if it is safe.

Recalls & Warnings

September 10, 2012

Maker of Concussion Recovery Supplement Warned For Making Drug Claims

On August 28, 2012, the FDA issued a warning letter to Trinity Sports Group, Inc. after a review of the company's websites found statements about Neuro Impact Concussion Response Formula constituted drug claims not permitted on supplements. 

Recalls & Warnings

April 29, 2014

Seller of B Vitamins, CoQ10, Amino Acids and Other Supplements Warned for Manufacturing Violations and Drug Claims

On April 1, 2014, the FDA issued a warning letter to Bio-Recovery, Inc.

Recalls & Warnings

May 14, 2014

Maker of Mood, Smoking Cessation Supplements and More Warned for Violations, Drug Claims

On April 17, 2014, the FDA issued a warning letter to CDJ Holding, Incorporated, d.b.a.