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CL Answer

Do probiotics help prevent urinary tract infections?

Find out if probiotics can help to prevent urinary tract infections (UTIs). Plus, information about other supplements that may help for UTIs, including cranberry and D-mannose.'s answer explains.

Clinical Update


A Chew for UTIs?

A study investigated whether a cranberry chew could inhibit infection-causing bacteria from binding to cells (which is necessary for urinary tract infections to occur) by testing participants' urine. Find out if it worked in our answer to the following question: Can cranberry juice or cranberry supplements prevent urinary tract infections (UTIs)?

CL Answer

Can cranberry juice or cranberry supplements help prevent urinary tract infections or improve overactive bladder?

Learn more about how cranberries, juice, and supplements can help prevent urinary tract infections, including safety.

Cranberry Juice for UTIs? -- cranberries and a glass of cranberry juice

Clinical Update


D-Mannose for Urinary Tract Infections?

See the latest research on whether D-mannose helps prevent UTIs.

Clinical Update


Comparison of D-Mannose Products – Used to prevent UTIs

We added comparisons of several brands of D-mannose to our answer to the question: Can D-mannose help prevent urinary tract infections?

Clinical Update


Uqora for UTIs (urinary tract infections)?

Uqora-Flush, a combination of D-mannose and other ingredients, is promoted for urinary tract health, but what is the evidence and is it worth the high price? Find out in our updated CL Answer about D-mannose for UTIs.

CL Answer

What are the health benefits of grapefruit seed extract (GSE)? Is it safe?

Learn more about grapefruit seed extract health benefits, including its possible antifungal and antibacterial effects and its safety.

Grapefruit with Extract and Spoon

Clinical Update


D-Mannose from Food?

A CL Member asked if it's possible to get a meaningful amount of D-mannose from food. Find out in our article about D-mannose and urinary tract infections, which includes information about D-mannose dosage and possible side effects.

Clinical Update


Cranberry for Cystitis in Men?

Cystitis (inflammation of the bladder) is common in men undergoing radiation therapy for prostate cancer. A study evaluated whether a cranberry supplement could reduce the incidence of cystitis in these men. Find out if it helped in our updated answer to the question: Are cranberry supplements helpful for men? Can they help with symptoms of prostatitis or urinary tract infections?

CL Answer

9 Supplements That May Help Reduce Nighttime Urination (And 4 That Might Not Help)

Waking up more than once during the night to use the bathroom? Learn more about the 9 supplements that may help and 4 others that don't.

A toilet in an empty bathroom at night

CL Answer

What are the health benefits of manuka honey, and is it safe?

Manuka honey health benefits, how it differs from common, store-bought honey, safety, evidence for using manuka honey for wounds, sore throat and cough, constipation and more.

Health Benefits of Manuka Honey -- jar of manuka honey

Product Review

Cranberry Juices and Supplements Review

CL's Tests Show Which Cranberry Juices and Supplements Are Best and Cost the Least

Clinical Update


Probiotic for the Urinary Tract?

Does taking a popular double-strain probiotic reduce the level of pathogenic microbes in the urinary tracts of women? See what a recent study found in the section about Vaginal bacterial infections of the Probiotic Supplements Review. Also see our Top Picks among probiotics.

CL Answer

Can lemon juice, lemonade, or other juices reduce my chances of getting kidney stones?

Information about lemon juice, lemonade, orange juice, cranberry juice and other juices for increasing urinary citrate and reducing the risk of kidney stones.

Lemon juice for kidney stones? -- glass of lemon juice and lemons

CL Answer

7 Supplements That May Help Treat Peptic Ulcers and 3 To Avoid

Peptic ulcers caused by H. pylori infection are typically treated with antibiotics, but certain supplements may also help. Find out which 7 supplements might be beneficial and which 3 should be avoided.

Supplements for peptic ulcer disease - young man with stomachache

Product Review

Mangosteen Juice and Supplements Review Article

What Are the Benefits of Mangosteen Juice and Supplements? Find Out What Mangosteen Can and Cannot Do For Your Health.

CL Answer

Are some probiotics dangerous? I've heard that Bacillus subtilis, a soil-based probiotic, can cause infections.

Find out if soil-based probiotic supplements are safe to take. Information about side effects, allergic reactions, infections and more.

Are probiotics safe? -- probiotic capsules and bottle

CL Answer

Does AZO Bladder Control really work for overactive bladder?

AZO Bladder Control information, including results from clinical studies on bladder control, dosage, and safety.

CL Answer

Is it true that drinking a small amount of hydrogen peroxide (H2O2) with water can kill bacteria in the urinary tract or help in other ways? Is this safe -- or is it dangerous?

Drinking or eating hydrogen peroxide (H2O2) can be dangerous and is not advised. Learn more treatments for urinary tract infections.

CL Answer

Are cranberry supplements helpful for men? Can they help with symptoms of an enlarged prostate, prostatitis, or urinary tract infections?

Learn more about how cranberry pills, cranberries, cranberry juice and supplements can help prevent urinary tract infections.

Cranberry Supplements for Men? -- Bottle of cranberry capsules

Clinical Update


Cranberry and UTIs

Two popular cranberry supplements promoted for urinary tract health were compared in a clinical study that showed one to be 4 times as effective as the other at preventing the adhesion of UTI-causing bacteria in urine. Get the details in our article about Cranberry and UTIs.

CL Answer

Can vitamin C from a supplement cause blood in the urine and painful urination?

Find out if vitamin C supplements can cause bloody or painful urination, or if this is due to contamination.

Vitamin C

CL Answer

What are the health benefits of tart cherry juice?

See the evidence for tart cherry juice health benefits from clinical studies. Find out if tart cherry has anti-inflammatory effects, if it can improve sleep, lower high blood pressure, or help for muscle pain and osteoarthritis.

Tart Cherry Benefits -- glass of cherry juice and two tart cherries

CL Answer

Can a probiotic help men with prostatitis?

Learn more about prostatitis, the effects of probiotics on prostatitis, and other natural treatments.

CL Answer

Can D-mannose help prevent urinary tract infections?

Learn more about D-mannose and its impact on urinary tract infections (UTIs), including evidence from clinical studies.

Woman with UTI holding her hands over her lower abdomen

CL Answer

Can any supplements reverse gray hair?

Nearly 75% of adults aged 45 to 65 are affected by gray hair. Learn about what causes gray hair and find out if any supplements can help.

A young woman shows gray hair on her head on a white background

CL Answer

Have you heard of the probiotic, Keybiotics? Does it do what it claims, and is it worth the money they charge?

Whole Body Research Keybiotics probiotic information, including its ingredients and possible cheaper alternatives.


News Release


Best Cranberry Juices and Supplements for Urinary Tract Infections

White Plains, New York, July 9, 2021 — Recent ConsumerLab tests of popular cranberry juices and supplements revealed that some products contained substantial amounts of key cranberry compounds that may help reduce the risk of urinary tract infections (UTIs), while others contained only small ...

CL Answer

Is ingesting colloidal silver helpful for any condition and is it safe to use?

Find out if there is evidence showing colloidal silver can help to treat infections, boost the immune system, help with arthritis and more, plus find out if colloidal silver can cause blue skin or other side effects.

Benefits and Risks of Colloidal Silver? -- dropper bottle of colloidal silver

CL Answer

Does Z-Stack multivitamin work to boost the immune system, and is it safe?

Find out about Z-Stack, including if it can help boost the immune system and if it is safe to use at the suggested dose.

A bottle of Z-Stack capsules

Clinical Update


Cranberry for Men?

Can cranberry extract reduce urinary frequency, urgency, and infections in men with benign prostatic hyperplasia (BPH)? Find out in the What It Does section of our Cranberry Juices and Supplements Review. Also see our Top Picks among cranberry juices and supplements.

CL Answer

Is it true that glutamine powder can help protect the stomach when taking NSAIDs like ibuprofen?

Find out if glutamine powder can help protect from stomach irritation when taking NSAIDs such as ibuprofen and aspirin.

Glutamine Powder in Small Scoop

CL Answer

Can glycine improve sleep or reduce nighttime urinary frequency?

Can glycine really help improve sleep? Lean more about glycine and its uses and benefits.

Glycine for Sleep and Nighttime Urinary Frequency? -- Older Man Sitting on Bed, Awake at Night

CL Answer

Do any supplements help for irritable bowel syndrome (IBS)?

IBS supplements may help reduce irritable bowel symptoms such as pain, diarrhea and constipation. Supplements include probiotics, melatonin, and flaxseed.

Supplements for IBS? -- Women With Stomach Pain

Clinical Update


Glycine for Urinary Frequency?

Can supplementation with the amino acid glycine improve symptoms of overactive bladder or reduce urinary frequency? See what a new study found in our updated answer to the question: Can glycine improve sleep or reduce nighttime urinary frequency?

CL Answer

Which vitamins and supplements should be stopped before getting blood work and laboratory tests?

Find out which vitamins and supplements can interfere with blood, urine or stool tests, and imaginging tests. Learn how B vitamins such as biotin, niacin and riboflavin, as well as calcium supplements, St. John’s wort, vitamin C, and others supplements can affect test results, as well as common foods that may interfere with tests.

Vitamin & Supplements to Stop Before Blood Tests

Clinical Update


Melatonin and Urinary Frequency

Can melatonin supplementation decrease nighttime urinary frequency in older women? See what a recent study found in the Concerns and Cautions section of the Melatonin Supplements Review.

CL Answer

What is Prelief? Does it really help for heartburn and/or bladder pain from acidic foods?

Prelief information, including what it has been claimed to do (such as helping with painful bladder, frequent urination, heartburn or indigestion from acidic foods), clinical evidence, and safety.

CL Answer

Titanium dioxide is listed as an ingredient in my supplement. Is it safe?

Titanium dioxide in supplements might have you concerned. Learn more about titanium dioxide - FDA status and evidence from studies on cancer.

Titanium Doxide Safety -- close up of broken white pills

CL Answer

Are lozenges and sublingual pills considered dietary supplements?

Learn more about lozenges and sublingual pills (such as echinacea, zinc and B12) including safety warnings.

Person in Yellow Holding Blister Pack and Red Lozenge

CL Answer

Just one dose of a horse chestnut extract (standardized to 20% aescin) caused me to have significant nausea and vomiting. Might there be a problem with the product?

Find out if horse chestnut side effects can include gastrointestinal discomfort such as nausea and vomiting.

Man Clenching Stomach

CL Answer

Do any supplements or foods benefit people with Crohn's disease? Are there any supplements that should be avoided?

Find out the most common vitamin and mineral deficiencies in people with Crohn's disease, including iron, B6, B12, vitamin D, zinc and others, plus evidence for N-acetyl-glucosamine (NAG), fish oil, and curcumin.

Supplements for Crohn's Disease -- Crohn's Disease Written on Notepad, Pills

CL Answer

Do probiotics really help prevent or treat vaginal yeast infections?

Information on using probiotics for treating and preventing yeast infections, including evidence from clinical studies.

Woman with Long Brown Hair Taking White Probiotic

CL Answer

Is it okay to take a zinc supplement while I am on an antibiotic for a respiratory infection?

Does zinc interfere with the absorption of antibiotics? Learn more about this and other effects in the body.

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.

Supplements for Coronavirus (COVID-19)? -- mask and pills

CL Answer

What are prebiotics? Is it important to look for them when choosing a probiotic supplement?

Learn more about prebiotics, including benefits and safety.

Prebiotics Health Benefits -- prebiotic supplement powder

Clinical Update


Pycnogenol for Prostate?

Pycnogenol, a branded form of pine bark extract, is promoted for a variety of uses, including improvement of circulation, cognition, joint pain and vision. It was recently given to men with benign prostatic hyperplasia (BPH) to see if it would improve urinary symptoms. Find out if it worked, and learn if it helps with other conditions, in our updated answer to the question: What is Pycnogenol and does it work? >>

Clinical Update


Vitamin D & Incontinence

Does giving high-dose vitamin D help women who have urinary incontinence? See what a recent study found in the What It Does section of the Vitamin D Supplements Review. Also see our Top Picks for vitamin D.

Clinical Update


Cranberry for Overactive Bladder?

Can cranberry supplements help with overactive bladder? See what a new study found in our article about Cranberry and Urinary Health.

Clinical Update


Vitamin D for Overactive Bladder?

Vitamin D supplementation may help vitamin D-deficient people who suffer from urinary urgency or frequency. Get the details in the What It Does section of the Vitamin D Supplements Review. Also see our Top Picks for vitamin D supplements.

Clinical Update


Glutamine for IBS?

Glutamine, an amino acid, plays a role in maintaining the digestive tract. Can taking it as a supplement help people with irritable bowel syndrome (IBS)? Find out what a recent study showed in the Glutamine section of the Muscle Enhancers Review.

Clinical Update


Does Vitamin D Improve Cancer Survival?

Does giving high-dose vitamin D to people with cancer of the colon or other parts of the digestive tract improve survival rates? Find out what recent studies are showing in the What It Does section of the Vitamin D Supplements Review. Also see our Top Picks for vitamin D supplements.

Clinical Update


Saw Palmetto May Not Work

It's used by many men hoping to reduce urinary symptoms caused by benign growth of the prostate, or BPH, but a new, well-designed study suggests that it doesn't work. Some other recent research suggest the same. Even when doubling and tripling the standard dose, the high-quality saw palmetto extract used in the new study failed to provide benefit.

What should you do? You may want to consider a different supplement -- beta-sitosterol, a phytosterol. The evidence remains fairly good for beta-sitosterol. To find out more about saw palmetto, beta-sitosterol, and the supplements we have tested, see the Prostate Supplements ReviewMore >>

Recalls & Warnings


FDA Warns Seller of Liquid Magnesium, B-12, Berberine & More

On December 9, 2021, the FDA issued a warning letter to Wholly Liquid Nutritional Supplements LLC because it found statements on the company's website and social media about its products, including SpiroLaze, BioLaze, LiquiLaurin, VIT-B12, DeStress, and Omega Plus, to be ...

Clinical Update


Protection from Past COVID Infection?

Find out if past COVID-19 infection protects against re-infection 12 months later based on two recent studies.

Clinical Update


Protection Due to Infection?

How well does a previous COVID-19 infection protect against BA.4/BA.5 infection? It depends on which COVID-19 variant caused the initial infection, according to a recent study.

Clinical Update


High-Dose Vitamin D Increases Upper Respiratory Infections

A study among older people found that taking a high dose of vitamin D every 2 months increased the risk of upper respiratory infection by 48% compared to taking low-dose vitamin D daily. Infections lasted two days longer for those taking the high dose versus the low dose. For details, including dosage, as well as our test reports on vitamin D supplements, see the Vitamin D Supplements Review >>

Clinical Update


Adequate Vitamin D Reduces Frequent Respiratory Infections

A study in people with frequent respiratory infections found that taking vitamin D for one year resulted in fewer infections than taking placebo. In contrast, a similar study did not find a benefit. Why the difference? Find out in the Vitamin D Supplements Review >>

Clinical Update


Omicron Infection May Be Just As Severe As Delta

Data from the U.K. suggests that Omicron infections may be as severe as those from Delta, in contrast to earlier findings from South Africa.

Getting a booster dose appears to provide significant protection against symptomatic infection with Omicron.

Clinical Update



Does Omicron infection protect against subsequent infections by new variants of Omicron, and do vaccines help? Find out what evidence suggests.

Recalls & Warnings


53 Protein, Meal Replacement and Nutritional Beverages Recalled Due to Bacterial Contamination

On July 29, 2022, Lyons Magnus LLC issued a recall of 53 protein, meal replacement, and nutritional beverages, including those sold under the brand names of Glucerna, Premier Protein, Oatly, and others, due to the potential for microbial contamination, including from Cronobacter sakazakii.

Recalls & Warnings


Nutrition Drink Recalled Due To Bacterial Contamination

On February 21, 2013, Sequel Naturals Ltd. issued a voluntary recall of three lots of Vega One French Vanilla nutritional shake due to bacterial contamination.

Recalls & Warnings


Manufacturer of Heart, Multivitamin, Cranberry, and Longevity Supplements Warned For Adulteration and Drug Claims

On January 29, 2013, the FDA issued a warning letter to M.D.R. Fitness Corp. following a facility inspection which found violations of good manufacturing practices which cause the company's products to be adulterated. 

Recalls & Warnings


FDA Seizes Probiotics Over Marketing Claims

On June 7, 2011, the U.S. FDA announced that, at its request, U.S. Marshals seized probiotic products from UAS Laboratories, Inc., of Eden Prairie, Minn. because the company markets the products as drugs.

Recalls & Warnings


Seller of NeuSilver Colloidal Silver for Adults, Children and Pets Warned by FDA

On February 19, 2019, the FDA issued a warning letter to iMedDo, Inc., following a review of the company's website, http://www.imeddo.

Recalls & Warnings


FDA Warns Seller of Vision, Calcium & Magnesium Supplements and More

On June 14, 2022, the FDA issued a warning letter to New Sun Inc. following inspection of the company’s website which found statements about the company’s products to be drug claims.

Recalls & Warnings


FDA Warns Muscle Sports for Joint Health, Immune & Workout Supplement, Vitamin C, Elderberry, and Other Claims

On September 23, 2022, the FDA issued a warning letter to Muscle Sports Products, LLC following inspection of the company’s websites which found statements about company products, including Join Revolution Capsules, IMMUNITY + Powder, Rhino Rampage PUMPED Capsules, Attack Pre-Workout ...

Recalls & Warnings


Maker of Omega-3, Saw Palmetto, St. John’s Wort Supplements And More Warned For Manufacturing Violations and Drug Claims

On March 19, 2013, the FDA issued a warning letter to Sunset Natural Products Inc.

Recalls & Warnings


Manufacturer of Green Tea, Vitamin E, Omega-3 and Cranberry Supplements Warned For Manufacturing Violations, Misbranding and Drug Claims

On October 16, 2012, the FDA issued a warning letter to dietary supplement manufacturer Advanced Nutritional Technology Inc.

Recalls & Warnings


Seller of Vision, Cholesterol, Prostate Supplements and More Warned for Drug Claims

On May 25, 2017, the FDA issued a warning letter to Herbal Doctor Remedies following a facility inspection and review of the company's websites,, and www.theraherb.

Recalls & Warnings


FDA Warns Sellers of Prostate, Reishi, Immune Products, and More

On March 16, 2021, the FDA issued warning letters to two companies following reviews of their websites which found statements made about the companies' products to be drug claims.

Recalls & Warnings


Pet Supplement Company Issues Recall Due To Potential Bacterial Contamination

On February 20, 2013, animal supplement company Nutri-Vet, LLC issued a recall of Nutri-Vet and NutriPet Chicken Jerky Products because they may be contaminated with Salmonella.

Recalls & Warnings


Seller of Aloe, Prostate and Joint Supplements Warned for Manufacturing Violations

On April 8, 2016, the FDA issued a warning letter to Salud Natural Entrepreneurs, Inc.

Recalls & Warnings


Pet Vitamin Recalled for Salmonella Risk

On June 22, 2010, the FDA reported that United Pet Group, Cincinnati, Ohio is voluntarily recalling all unexpired lots of its PRO-PET ADULT DAILY VITAMIN Supplement tablets for Dogs due to possible Salmonella contamination. This product is not among those included in ConsumerLab.

Recalls & Warnings


Seller of Herbal Extracts Warned for Manufacturing Violations, Drug Claims

On November 3, 2014, the FDA issued a warning letter to Avena Botanicals, Inc.

Recalls & Warnings


Seller of Meal Replacement, Protein Drinks, Cranberry and More Warned for Manufacturing Violations

On July 6, 2017, the FDA issued a warning letter to Professional Botanicals, Inc.

Recalls & Warnings


Expansion of Pet Supplement Recall for Salmonella Risk; Many Brands Affected

On July 2, 2010, the U.S.

Recalls & Warnings


Prebiotics Recalled For Salmonella Risk

On September 4, 2012, Eco Health, Inc. announced a recall of its florAlign Prebiotic Formula (Powder) due to the potential for the product to be contaminated with Salmonella.

Recalls & Warnings


Men's Fiber Supplement Recalled

On January 21, 2018, Break Ventures/California Basics recalled of its fiber supplement for men, Zero for Him (150 count) due to possible Salmonella contamination.

Recalls & Warnings


FDA Warns of Life-Threatening Side Effects and Withdrawal Symptoms from Two Arthritis, Muscle Pain Supplements

On August 21, 2012, the FDA issued a warning to consumers about the dangers of taking Reumofan Plus and Reumofan Plus Premium, two dietary supplements marketed for arthritis, osteoporosis and muscle pain.

Recalls & Warnings


27 Cases of Salmonella Infection Linked to Recalled Garden of Life Organic Shakes

On March 24, 2016, the Center for Disease Control and Prevention (CDC) announced that 27 cases of Salmonella infection, including five which required hospitalization, are now linked to recalled Garden of Life Raw Meal Organic Shake and Meal Replacement products.

Recalls & Warnings


Tea Recalled Due to Salmonella Risk

On March 11, 2016 Awareness Corp. issued a recall of its 7.4 ounce container of Boost Tea because it may be contaminated with Salmonella.

Recalls & Warnings


Garden Of Life Recall Expanded

On February 13, 2016, Garden of Life LLC expanded its January 2016 recall of certain Raw Meal Organic Shake & Meal Chocolate, Original, Vanilla and Vanilla Chai products to include additional lots of these products, because they have the potential to be contaminated with ...

Recalls & Warnings


FDA and FTC Warn: Supplements Cannot Prevent, Treat Or Cure Cold And Flu

On February 11, 2013, the FDA and the Federal Trade Commission (FTC) jointly issued warning letters to three dietary supplement companies regarding their potential illegal marketing of products to prevent, treat or cure flu virus.

Recalls & Warnings


Maker of Red Yeast Rice, St. John's Wort, Valerian and More Warned for Manufacturing Violations, Drug Claims

On December 2, 2015, the FDA issued a warning letter to Nature's Health, LLC, following a facility inspection which found the company's product, including Ginkgo & Rhodiola, Blood Sugar Balance IV, Cinnamon Extract, Choles-Balance Red Yeast Extract, Lecithin, Milk Thistle Seed Extract, ...

Recalls & Warnings


More Carob Powder Products Recalled

On September 22, 2014, Glaser Organic Farms issued a recall of Raw Carob Powder and Carob Fudgy Brownie because they have the potential to be contaminated with Salmonella.

Recalls & Warnings


Baby Supplement Recalled Due To Salmonella Risk

On July 20, 2012, Wellements LLC issued a voluntary recall of Baby Move Prune Concentrate because testing of retained raw materials used in the product found one ingredient to be positive for Salmonella.

Recalls & Warnings


FDA Warns Consumers to Avoid Breath Supplement Contaminated with Lead

On May 3, 2010 the U.S. Food and Drug Administration warned consumers not to purchase nor consume Vita Breath, a dietary supplement manufactured by American Herbal Lab Inc. of Rosemead, Calif.

Recalls & Warnings


Seller Warned for Promoting Essential Oils to Treat Flu, MRSA, Measles and More

On September 22, 2014, the FDA issued a warning to doTERRA International, LLC.