Clinical Updates

Green tea may significantly increase blood levels of a common medication for men. Get the details in the Concerns and Cautions section of our Green Tea Review, which includes information about many other green tea interactions, including with statins and blood-thinners.

Also see our Top Picks among green tea beverages and supplements.

Baking soda may temporarily relieve heartburn but be aware that overuse can have adverse effects. Get the details in our article about supplements and foods for reflux and heartburn.

Also see our Top Picks among alginate supplements for reflux.

Iron deficiency can cause an underactive thyroid (hypothyroidism), but it’s important that iron not be taken at the same time as thyroid medication. Get the details in our Iron Supplements Review, which includes our Top Picks for iron.

Also see our article about supplements and thyroid function.

Low blood levels of vitamin D have been linked with higher migraine frequency. A new study suggests why. Get the details in our Vitamin D Supplements Review, which includes our Top Picks for vitamin D.

Also see our article about supplements and migraine.

Are Hormone Harmony (for menopause) and other Happy Mammoth supplements worth taking? We reviewed the evidence. See our conclusions in our article about these products.

Also see our take on The 'Pause Nutrition supplements by Dr. Mary Claire Haver.

Did nicotinamide riboside improve memory, attention or cognition among older people with cognitive decline in a recent study? Find out in the Nicotinamide riboside section of our NAD Booster Supplements Review, which includes our Top Picks for nicotinamide riboside.

Also see: Do any supplements, foods or lifestyle modifications help with brain function, like memory and cognition?

Did taking shatavari (wild asparagus) help increase muscle strength in women doing resistance training in a recent study? Find out in the Shatavari section of our Menopause Supplements Review.

Also see our article: Best Supplements to Prevent Age-Related Muscle Loss

A CL member experienced elevated liver enzymes after taking Provitalize, a supplement promoted to help with menopausal weight gain and joint pain. Other cases have been reported. Get the details in our article about Provitalize.

Also see our Menopause Supplements Review and our take on other supplements promoted for menopause relief, including Happy Mammoth’s Hormone Harmony and The 'Pause Nutrition Supplements by Dr. Mary Claire Haver.

Tea tree oil has been traditionally used for healing cold sores, but does it work? Find out what research suggests in the Tea tree oil section of our Essential Oils Review, which includes our Top Pick for tea tree oil as well as for lavender oil.

Also see: Can any vitamins or minerals help prevent or reduce canker sores or cold sores?

A CL member asked if sorbitol in Flintstones multivitamins poses a risk. See our discussion about this in our Multivitamin Review, which includes our Top Pick multivitamins for children and adults.

Also see our article: Sugar Substitutes: Pros, Cons, and Best Choices.

Did taking CoQ10 reduce the severity of tinnitus (ringing in the ears) in a recent study? Find out in the Tinnitus section of our CoQ10 & Ubiquinol Supplements Review, which includes our Top Picks for CoQ10 and ubiquinol.

Also see our article about supplements that may help or worsen tinnitus, which includes information about lifestyle modifications that may help and medications that may cause tinnitus.

A “natural” toothpaste was recently found to contain lead. See our take on this in the Natural toothpastes section of our article on dental products.

Also, find out if flavorings in toothpaste can cause mouth irritation.

Many products sold in California have "Prop 65" health warnings about chemicals they contain, but without naming the chemicals. A new law requires more detail, but companies have years to comply. Learn more in our article about California Prop 65 warnings.

Also see our article about which foods and supplements are most likely to be contaminated with dangerous heavy metals, based on our tests.

Does supplementing with protein lead to greater muscular benefits in older people involved in resistance training? See what a recent review of studies concluded in the Building and maintaining muscle mass section of our Protein Supplements Review, which includes our Top Picks among protein powders, shakes, and drinks.

Also see: Best Supplements to Prevent Age-Related Muscle Loss

Did taking a prebiotic supplement (Sunfiber) improve winter skin health in middle-aged people? Find out in the What It Does section of our Prebiotic Supplements Review, which includes our Top Picks among prebiotic supplements.

Also see: Do any supplements reduce wrinkles, increase skin elasticity, or tighten the skin?

Does taking L-carnosine improve cognitive function in healthy people? Find out what a recent study showed in our article: Are L-carnosine supplements helpful and safe?

Also see: Do any supplements, foods or lifestyle modifications help with brain function, like memory and cognition?

Does taking PEA (palmitoylethanolamide) reduce menstrual cramp pain? Find out what a recent study showed in our article: What are the health benefits of palmitoylethanolamide (PEA), and is it safe?

Also see: Do any supplements help reduce menstrual pain or symptoms of premenstrual syndrome (PMS)?

Did taking Juice Plus+ improve cognitive function in a recent study? Find out in the What It Does section of our Fruits, Veggies, and Other Greens Supplements Review, which includes our Top Picks among products.

Also see: Do any supplements, foods or lifestyle modifications help with brain function, like memory and cognition?

Might taking magnesium with meals reduce the risk of kidney stones? Find out in our Magnesium Supplements Review, which includes our Top Picks among magnesium supplements.

Also see: Which supplements and foods reduce or increase the risk of kidney stones?

Did taking curcumin decrease weight in people with inflammatory bowel disease? See what a recent study found in the What It Does section of our Turmeric & Curcumin Supplements Review, which includes our Top Picks among turmeric and curcumin supplements and spices.

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

Twenty-nine out of 39 supplements containing the "NAD booster" nicotinamide riboside were recently found to contain much less ingredient than claimed, with many containing under 1%. Counterfeit versions of Tru Niagen were also identified. Details are in our NAD Booster Supplements Review, which includes our Top Picks among products.

Also see our article about avoiding counterfeit supplements online.

Does taking jiaogulan (Gynostemma pentaphyllum) improve hair thickness? Find out what a recent study showed in our article about supplements for hair.

Also see: Does Gynostemma pentaphyllum really work as an AMPK activator and help for diabetes, high cholesterol, or weight loss?

Did taking vitamin D help people with a common form of vertigo? See what a recent study found in our Vitamin D Supplements Review, which includes our Top Picks for vitamin D.

Also see: Do any supplements improve balance or reduce the risk of falls?

Taking high-dose biotin can cause blood tests to show falsely high levels of testosterone and/or cortisol, as shown in recent cases. It can interfere with many other tests, as well. Get the details, in the Biotin section of our B Vitamin Supplements Review. Also see our Top Picks for biotin.

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

Several cases of liver injury and liver failure have been linked with the use of supplements containing Garcinia, a popular ingredient for weight management. Get the details in the Concerns and Cautions section of our Garcinia Cambodia (HCA) Supplements Review.

Also see: Is there a risk of liver toxicity with certain supplements?

Does taking licorice root extract reduce heartburn or other symptoms of gastroesophageal reflux? Find out what a recent study showed in our article about supplements for reflux.

Also see our article about concerns with licorice root.

Does turmeric or curcumin interfere with estrogen medication? Find out in the Concerns and Cautions section of our Turmeric and Curcumin Review, which includes our Top Picks among turmeric/curcumin supplements and spices.

Also see our article about estrogen creams for wrinkles.

Does taking glycine reduce the frequency or severity of tinnitus (ringing in the ears). Find out what’s known in our article about glycine.

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

Use of a multiwavelength light device may slow progression and improve vision among people with age-related macular degeneration (AMD), according to a recent study, but not all light devices show a benefit. Get the details in our article about the health benefits and safety of red and near infrared light.

Also see our Vision Supplements Review, which includes our Top Pick for slowing macular degeneration.

Did a zinc supplement decrease gum bleeding or inflammation in men and women with moderate to severe gum disease in a recent study? Find out in the What It Does section of our Zinc Supplements and Lozenges Review, which includes our Top Picks for zinc.

Also see our article about supplements for gum disease and our Top Pick toothpaste and mouthwash for bleeding gums.

Did supplementing with hydrolyzed collagen along with resistance training improve leg strength in middle-aged men? Find out what a recent study showed in the Building muscle and muscle strength section of our Collagen Supplements Review.

Also see our Top Picks for collagen for joints and tendons and collagen for skin.

Did taking a relatively low dose of fish oil or krill oil reduce depression or anxiety in people with major depressive disorder? See what a recent study found in the Depression section of our Fish Oil Supplements Review, which includes our Top Picks among fish oil, krill oil, algal oil, and other omega-3 supplements.

Also see: What are the best supplements for depression and anxiety?

Find out in which order you should apply sunscreen and insect repellent in our article about bug sprays for preventing tick and mosquito bites, which includes our Top Pick among repellents.

Also see our article: What is the best sunscreen based on safety and efficacy?

How much calcium do you get from drinking water? Find out in our article: How much calcium do you need each day, what forms are best, and how much is too much?

Also see our Calcium Supplements Review for our Top Picks for calcium supplements.

If you have trouble swallowing pills, be particularly cautious with iron pills, as highlighted by a recent report. Get the details in the Concerns and Cautions section of our Iron Supplements Review, which includes our Top Picks among iron supplements, including liquid and chewable iron.

Also see: 7 Tips to Avoid Getting a Pill Stuck in Your Throat

Does consuming oat β-glucan reduce levels of toxic PFAS ("forever chemicals") in the body? See what a recent analysis found in the Benefits of Oats section of our Oats Review, which includes our Top Picks for rolled ("old-fashioned") and steel-cut oats.

Also see our Top Pick water filter pitcher for removing PFAS from water, and our article about avoiding PFAS in food, water, and other products.

Can iron deficiency cause tinnitus (ringing in the ears)? Find out in the Iron Deficiency and Anemia section of our Iron Supplements Review, which includes our Top Picks among iron supplements.

Also see our article about tinnitus and supplements.

Find out if Tetley tea bags contain plastic in the Concerns with Plastic Tea Bags section of our Green Tea Review, which includes information about plastics in tea bags from Bigelow, Numi, Republic of Tea, Tazo, Trader Joe’s, and Twinings.

Also see our Top Picks for green tea (including tea bags, loose leaf tea, bottled teas, matcha, and supplements).

Did taking cocoa extract slow macular degeneration (AMD) in older people? Find out what a recent study showed in the Vision section of our Dark Chocolates, Cocoa & Cacao Powders, Nibs, and Supplements Review, which includes our Top Picks among supplements, cocoas and mixes, dark chocolates and chips, and cacao nibs.

Also see our Top Picks AREDS formulas to slow the progression of AMD in our Vision Supplements Review.

A group recently reported significant amounts of lead in 15 to 33% of prenatal supplements and prescription vitamins. Read more in the Quality Concerns section of our Multivitamins Review, which includes our Top Picks among multivitamins, including prenatal vitamins.

Also see: Which foods and supplements contain lead, cadmium, or arsenic?

Did taking ashwagandha improve quality of life or bone mineral density in postmenopausal women? Find out in the What It Does section of our Ashwagandha Supplements Review, which includes our Top Picks for ashwagandha.

Also see if taking shatavari helped postmenopausal women in a recent study.

Learn the "dos and don'ts" of using insect repellent along with sunscreen for these to be safe and effective in our article about choosing insect repellents.

Also see our article about safe sunscreens.

Prevagen recently won a lawsuit filed against sellers of counterfeit Prevagen. Get the details in our article about Prevagen, which also reviews its effects on memory and the history of its marketing claims.

Also see our article about how to avoid counterfeits online.

Does taking a prebiotic supplement with dieting reduce weight or improve liver health among people with fatty liver disease? Find out what a recent study showed in the What It Does section of our Prebiotic Supplements Review.

Also see our article: Do any supplements help with fatty liver disease? Are some diets more beneficial than others?

Did taking vitamin D for more than 5 years reduce the risk of type 2 diabetes among healthy older people in a major U.S. study? Find out in the Diabetes, insulin resistance and glucose control section of our Vitamin D Supplements Review.

Also see our Top Picks for vitamin D.

And see our article: Which supplements and foods can help lower or control blood sugar?

A CL member informed us that one of our Top Picks for dark chocolate was found to contain toxic phthalate compounds in tests by an independent group. See our take on these findings in our Dark Chocolate and Cocoa Review, which includes our Top Picks for dark chocolate and cocoa powder.

Also see the levels of plasticizers found in one of the canned tunas we've tested and the popular "greens" supplement AG1.

Did taking vitamin D provide extra relief to people with seasonal allergies already using a nasal antihistamine? Find out what a recent study showed in the Allergies section of our Vitamin D Supplements Review, which includes our Top Picks for vitamin D.

Also see: Which supplements are best for seasonal allergies?

Did taking lion’s mane improve cognition or mood in a recent study? Find out in the What It Does section of our Lion's Mane and Chaga Supplements Review, which includes our Top Pick for lion’s mane.

Also see: Do any supplements, foods or lifestyle modifications help with brain function, like memory and cognition?

There has been concern that creatine might cause loss of hair through a hormonal effect. A new study looked at this issue more directly. Find out what the study showed in the Concerns and Cautions section of our Muscle Enhancers Review, which includes our Top Pick for creatine.

Also see our article about supplements for hair.

Did taking PEA (palmitoylethanolamide) plus melatonin reduce migraine attacks in a recent study? Find out in the Health Effects section of our article about PEA, which includes our comparison of PEA products.

Melatonin, alone, has also shown some benefit with migraine, as noted in our Melatonin Supplements Review, which includes our Top Picks for melatonin.

Did taking a probiotic improve memory or cognitive function in healthy older men and women? See what a recent study found in the Cognitive function section of our Probiotics Supplements Review, which includes our Top Picks among probiotics.

Also see: Do any supplements, foods or lifestyle modifications help with brain function, like memory and cognition?

Does taking vitamin D during winter months reduce colds and other respiratory infections? Find out what a recent study showed in the Respiratory infection, colds, and influenza section of our Vitamin D Supplements Review, which includes our Top Picks for vitamin D.

Also see our article: Do any supplements help prevent or treat a cold?

Taking psyllium on top of standard medical treatment may help improve symptoms of laryngopharyngeal reflux, a type of acid reflux that affects the throat, according to a recent study. Details are in the What It Does section of our Psyllium Fiber Supplements Review, which includes our Top Picks among psyllium supplements.

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

Did taking Nutrafol SKIN reduce acne in women? Find out what a recent study showed in our article about supplements for acne.

Also see our article about Nutrafol for hair.

An independent group recently tested 9 matcha green tea powders and reported that levels of lead and other heavy metals far exceeded "Action Levels." Get our take on this and how the results to compare our own in our Green Tea Review, which includes our Top Picks for matcha and other green teas.

Another popular NAD+ supplement sold on Amazon was found to contain far less NAD+ than claimed, according to tests by a competing supplement company. For details, and results for 21 other NAD+ products, see the Quality Concerns section of our NAD Boosters Review. Also see our Top Picks among NAD Boosters.

Did taking melatonin reduce nerve pain? See what a recent study showed in the Other Uses section of our Melatonin Supplements Review.

Also see: Do any supplements, like Nervive, help with nerve pain, like sciatica, diabetic neuropathy or postherpetic neuralgia?

Does rinsing the mouth with dilute manuka honey improve symptoms of dry mouth? Find out what a recent study showed in the What It Does section of our Manuka Honey Review, which includes our Top Picks.

Also see:Do Any Supplements Improve Dry Mouth (Xerostomia) or Make It Worse?

Can taking this compound increase the risk of anemia? Find out what research suggests in the Concerns and Cautions

Due to its popularity among CL members, we recently tested Kirkland Triple Action Joint Supplement, which contains a "proprietary" UC-II cartilage blend. See what we found in our Collagen Supplements Review, which includes our Top Pick for collagen for joints and for skin.

Also see our recent Joint Health Supplements Review, covering glucosamine, chondroitin, MSM, and Boswellia.

Salmon is a good source of astaxanthin, an antioxidant. A new study suggests how salmon can be cooked to preserve astaxanthin, and why levels are lower in canned salmon.

Also see our Astaxanthin Supplements Review for information about its potential uses, safety concerns, and our Top Picks among astaxanthin supplements.