Vitamin B12 Supplementation - Does it Work?

Updated: Oct 10, 2021

Hey Readers! I am so happy you are here! Sorry that this post is delayed by one week. Life has been pretty busy and hectic for me lately, and I just simply ran out of time over the past few weeks to work on my blog. In today’s post, I am going to give a brief overview of what the research seems to suggest regarding supplementation with vitamin B12 and physical performance.

Vitamin B12, a micronutrient (click here to read more about micronutrients) also known as cobalamin, is actually a general term that refers to several cobalt-containing compounds. Cobalamin is actually produced by bacteria and enters the food chain via herbivores, which accumulate it during intestinal fermentation of grass. There is currently no clear consensus regarding the appropriate amount of serum (i.e. blood) vitamin B12 in healthy individuals, but some research has suggested that the lower cut-off point ranges from 100 – 350 pg/mL (picograms/milliliter). It is also suggested that vitamin B12 deficiency is present in about 6% of healthy, young adults, and the rates of deficiency increase with age, vegan diet practices, and those with GI disorders.

Vitamin B12 is essential in a wide variety of metabolic processes throughout the entire body, including: metabolism of fats and proteins, processing of DNA and RNA, red blood cell (RBC) formation and functioning, proper immune function, transmission of neural signals, and synthesis of various neurotransmitters. There is also evidence of a relationship between low blood levels of vitamin B12 and blood vessel dysfunction, mitochondrial dysfunction, muscular weakness, and altered physical and neuromuscular performance. Athletes and non-athletes alike commonly supplement with vitamin B12 given its myriad roles in the functioning of the human body. The question is, however, does vitamin B12 supplementation appear to improve physical performance? Let’s talk about some recent research that evaluated this exact question.

Vitamin B12 and Athletic Performance?

Kyzywanski et al. (2020) studied the relationship between vitamin B12 levels and RBC functioning in athletes. RBCs are essentially responsible for transporting oxygen around to your working tissues, which is obviously super important for athletes, as oxygen is required for the aerobic energy production systems in the body. In this study, fasting blood was drawn from both strength-training (e.g. weightlifters) and endurance-training (e.g. runners) athletes who used vitamin B12 supplements within the past 3 months. Serum vitamin B12 levels were measured as well as various RBC parameters, such as hemoglobin levels (i.e. the protein involved in binding to oxygen within the RBC) and hematocrit (i.e. the percentage of RBCs in the blood).

The authors found a weak, but positive, correlation between vitamin B12 serum concentration and hemoglobin and hematocrit levels, meaning that when serum vitamin B12 levels increased, so did hemoglobin and hematocrit. The increased hemoglobin and hematocrit may result in better oxygen delivery to working muscles during exercise. Interestingly, the authors found that the positive correlation was stronger in endurance athletes compared to strength-training athletes. Additionally, it seemed that the most effective vitamin B12 serum concentration was between 400 to 700 pg/mL. The authors concluded that in light of the improved RBC parameters, athletes might want to consider regular oral supplementation with vitamin B12, and also regularly monitoring blood vitamin B12 concentration to ensure that their serum levels stay within the 400 – 700 pg/mL range.

Vitamin B12 and Physical Performance in Older Adults?

Swart et al. (2016) examined the effect of daily vitamin B12 supplementation on changes in physical performance, handgrip strength, and the risk of falling in individuals aged 65 and older over a 2-year period. The study was a double-blind, randomized, placebo-controlled trial. Participants supplemented daily with an oral supplement containing 500 micrograms of vitamin B12 (as well as folic acid and vitamin D) or a placebo tablet containing vitamin D only. Physical performance was assessed with three function tests - 1) Walking test, where the time needed to walk three meters back and forth as quickly as possible was measured; 2) chair stands, where the time needed to stand up and sit down on a chair without using hands was measured 5 times; and 3) tandem stand, where the ability to stand with the feet right in front of each other for 10s with eyes open was assessed. Handgrip strength was measured with a hand held dynamometer. Falling was assessed prospectively, where weekly falls were documented on a calendar for three months.

Results showed that while both groups showed a decline in physical performance over the 2-year investigation period, those in the vitamin B12 group showed small improvements in walking test. There were no significant differences between the two groups in handgrip strength or the number of falls. Thus, the authors concluded that vitamin B12 supplementation did not appear to be effective in improving chair stands, tandem stands, and handgrip strength, or in reducing the number of falls. Vitamin B12 supplementation appeared to improve walking ability, although this effect was small.

Vitamin B12 and Lung/Heart Functioning?

Paulin et al. (2017) examined vitamin B12 supplementation on lung and heart functioning in individuals with chronic obstructive pulmonary disease (COPD). It has been shown that patients with COPD have lower vitamin B12 levels compared to those without COPD. In this study COPD patients were randomly assigned to one of four groups – 1) those receiving pulmonary rehab AND vitamin B12 supplementation; 2) those receiving pulmonary rehab and placebo; 3) those receiving vitamin B12 supplementation only without pulmonary rehab; and 4) those receiving placebo only. The vitamin B12 supplement contained 500 mg of B12, and was supplemented for 8 weeks, while the placebo contained maltodextrin (a type of sugar). Participants in the rehab and supplementation groups completed aerobic exercise (cycle ergometer) and resistance training (RT) for 8 weeks. Spirometry, a way to measure lung function, was completed on all participants before, and after, the experimentation period. Cardiopulmonary exercise testing (CPET) was also performed before and after experimentation to determine the endurance and kinetics of oxygen consumption during exercise. Finally, the participants’ blood was analyzed for vitamin B12 levels before and after the experiment.

The results showed that there was a small, but positive, trend for improved aerobic performance (endurance) on the cycle ergometer in the supplemented groups compared to the non-supplemented groups. Thus, there is a positive effect, although slight, on endurance through supplementation with cobalamin. However, there did not appear to be any differences between the groups for the CPET measures.


Vitamin B12 supplementation may improve RBC parameters in athletes, walking biomechanics in older individuals, and endurance in patients with COPD. Vitamin B12 supplementation may not improve handgrip strength, risk of falling, or CPET measures. So, is vitamin B12 helpful for physical performance? To me, the data is inconclusive. It does not appear that there is overwhelming data to suggest that vitamin B12 supplementation is definitely going to improve physical performance, but it also does not appear that vitamin B12 supplementation does nothing. The data also seems to suggest that vitamin B12 may provide the most benefit for endurance-related activity, such as walking, running, or using the cycle ergometer. So, should you supplement with vitamin B12 to improve your overall physical parameters? I think that is best left up to you to answer. If you are an endurance athlete/exerciser, vitamin B12 supplementation may in fact be a good choice for you. Even if you are not an endurance athlete, vitamin B12 may still be helpful for your physical functioning.

As always, the information presented in this blog post is derived from my own study of nutrition, human movement, anatomy, and yoga. If you have specific questions about micronutrition for your body, please consult with your physician, dietician, personal trainer, or private yoga teacher. If you are interested in private yoga and/or personal training sessions with me, Jackie, email me at for more information about my services. Also, please subscribe to my website so you can receive my monthly newsletters (scroll to the bottom of the page where you can submit your email address). This will help keep you "in-the-know" about my latest blog releases and other helpful yoga and wellness information. Thanks for reading!

~Namaste, Jackie Allen, M.S., M.Ed., CCC-SLP, RYT-200, RCYT, NASM-CPT, NASM-CES


Krzywanski, J. et al. (2020). Vitamin B12 Status and Optimal Range for Hemoglobin Formation in Elite Athletes. Nutrients. 12(1038): 1 – 13.

Mosegaard, S. et al. (2020). Riboflavin Deficiency – Implications for General Human Health and Inborn Errors of Metabolism. International Journal of Molecular Sciences. 21 (3847): 1 – 26.

Paulin, F.V. et al. (2017). Addition of vitamin B12 to exercise training improves cycle ergometer endurance in advanced COPD patients: A randomized and controlled study. Respiratory Medicine. 122: 23 – 29.

Rogerson, D. (2017). Vegan diets: practical advice for athletes and exercises. Journal of the International Society of Sports Nutrition. 14(36): 1 – 15.

Swart, K.M., et al. (2016). A Randomized Controlled Trial to Examine the Effect of 2-Year Vitamin B12 and Folic Acid Supplementation on Physical Performance, Strength, and Falling: Additional Findings from the B-PROOF Study. Calcified Tissue International. 98: 18 – 27.

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