About ConsumerLab.com


B Vitamins

Answer:

Although B vitamins are water soluble and don't stay long in your body, large doses of certain B vitamins can cause serious toxicity, as summarized below. The same is true of vitamin C, the other water soluble vitamin.

Unfortunately, there is no requirement for supplement labels to warn of these toxicities. As we have shown in our B Vitamin Supplements Review, many vitamins and energy drinks exceed the established Tolerable Upper Intake Levels (which vary by age) for B vitamins. If you have an established deficiency, high doses may be necessary; otherwise, remember that "more" does not necessarily mean "better."

Toxicities from B Vitamins

B-3 (Niacin) Skin flushing/pain; liver toxicity; elevated blood sugar
B-6 Nerve damage, skin lesions
B-9 (Folate/Folic Acid) Kidney damage; masking of B-12 deficiency
B-12 Acne/rosacea a side effect in some people

 


More information about the beneficial and toxic effects of these vitamins, including associated dosage, is found in the B Vitamin Supplements Review.

 

Join today to unlock all member benefits including full access to all CL Answers and over 1,400 reviews.

Join Now

Join now at www.consumerlab.com/join/

13 Comments

Nancy4389
April 24, 2022

After dealing with B vitamin deficiencies for many years despite having super healthy diet, my experience is that high dose vitamins/supplements make a huge difference in quality of life. Being able to metabolize vitamins is as important as being able to absorb vitamins. After reading many legitimate scientific articles on nutrition and spending years going to specialists (many not covered by insurance), I found there is a connection between my autoimmune, intestinal, neurological and pain problems. After a lifetime of anemia and years of increasing health problems I started using functional medicine doctors and new, more sophisticated nutritional and genetic tests--most not covered by insurance. I have multiple SNPs associated with problems absorbing and processing folate & B12. I found that if you are chronically folate & B12 deficient, you are likely to become deficient in more B vitamins and other critical metabolic and mitochondrial functions that are important to health. For me, high dose, high quality B vitamins have made the difference between being able to successfully manage medical/health/malabsorption challenges and wanting to crawl in a corner and die. (Think long Covid type problems!) I use ConsumerLab for every supplement that my doctors recommended and I've spent hundreds of hours reading medical articles and recent research on B Vitamins. Taking the right kind of high dose B vitamins along with other critical minerals & supplements has greatly reduced my pain, increased my energy, cleared brain fog, and improved my ability to eat & digest food. It takes time & patience to overcome severe nutritional problems but I can now eat without feeling like I'm going to throw up after every meal, I don't get sick all the time, & I take fewer painkillers, & I'm happier. I found the adverse effects of high dose B vitamins went away completely when I changed the QUALITY of what I was taking. Knowing what is going on in your body through more advanced genetic & nutrition tests, and physicians who are able to spend more time learning about genetics/nutrition and interpreting tests relevant to your medical history & symptoms makes all the difference in the world. ConsumerLab greatly increases my ability to make better decisions in my supplementation and I save money. Many of the doctors I've seen don't have time to stay updated on nutrition, testing and genetics--and how could they with all the recent developments in so many areas of medicine?

Marsha4391
July 03, 2023

Thank you for telling your story. I’ve been chronically I’ll for half my life, and as I get older it gets worse.

victoriak
June 24, 2024

I really appreciate you sharing this information. The symptoms you describe sound so similar to mine, although it is other B vitamins I'm deficient in.

HF
May 30, 2021

I have been taking a B-50 supplement, thinking it was a wise choice. Now I know differently and I am grateful to ConsumerLab. I would like to know of any product that has the RDA, especially of B-12, but other B vitamins would also be helpful. I tried a vitamin C liquid so that I could adjust the dose. It was in glycerin, and just 1/8 tsp per day gave me a mild headache and dry mouth after a few days. Fortunately there are C crystals that can be adjusted. It is hard to believe that no company is making B-vitamin supplements for those who are not deficient. I would very much appreciate any advice. Thank you!

DianeR
July 06, 2020

According to a new peer reviewed study, niacinamide (not niacin) 500 mg twice a day has been shown to be safe and effective in lowering non melanoma skin cancer rates by 23%. This is a very encouraging study for those of us with substantial sun exposure and ongoing skin cancers as a result. My dermatologist just recommended that I start this after yet another Moh's surgery. I came looking for a brand of niacinamide to buy. This should be noted in consumerlab for those investigating niacinamide/nicotinamide.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4570055/#:~:text=The%20pill%E2%80%94the%20vitamin%20B,common%20precancer%20of%20the%20skin.

ConsumerLab.com
July 07, 2020

Actually, the study you reference is from 2015 and we wrote about it then. We noted some important caveats to the findings. Details are in our B Vitamin Supplements Review, at https://www.consumerlab.com/reviews/review-best-b-vitamins-and-complexes-energy-b6-b12-biotin-niacin-folic-acid/bvitamins/#skincancer

Janice4382
October 18, 2015

there is something odd about B6- I know of several people who have had blood tests that showed elevated levels of B6- tested because of peripheral neuropathy symptoms- and were not taking any or lower dose B supplements. have others heard of this?

Stan4383
March 29, 2017

Natural food sources?

Marysue4378
July 23, 2015

What about the use of B 50 along with Biotin and D 3 for nails & hair?

ConsumerLab.com
July 31, 2015
sharon4377
July 08, 2015

I took 5000 B12 two times a day and developed hives on both arms. I was taking it for phantom pain. Hives disappeared when I stopped taking such a large dose.

Beth (Elizabeth J)4376
July 05, 2015

I order a B complex that is called B natural complex. It is made up of all the B vitamins in the suggested daily dose.

The only one I have been able to find is by Nutrilite - sold by Amway.

Martha4374
July 05, 2015

I had a similar neurological reaction to too much B-6 and folic acid. You will slowly recoup your nerve function if you stop taking B vitamins and concentrate on just eating healthily. Check with your doctor to see if you have a genetic condition such as hemochromatosis. If you do - you can definitely take too much vitamin C. In this condition the liver hangs on to too much iron and seems to be more vulnerable to other toxicities. Some of us also have genes that require folate instead of folic acid - I am always searching for vitamins and foods that don't have folic acid added. I avoid most baked goods and bread for that reason. You are smart to be asking these questions

Join the conversation

(0/2500)