The libraryFocus
Vitamin B12
A normal blood B12 misses it, and methylmalonic acid catches it.
Also called Cobalamin, Cyanocobalamin, Methylcobalamin, Hydroxocobalamin, Adenosylcobalamin
The item
Three squares: proven in human trials. Two: a strong signal. One: early human data. Striped: the trials disagree.
Start today
- Ask for a methylmalonic acid test at your next blood draw.
Why it works
It is a helper for exactly two human enzymes, and each one leaves a clear sign when it fails. Without B12, homocysteine cannot be recycled into methionine and the methylation system falters. That also traps folate in a form the body can't use, which is why the two deficiencies look alike. When the second enzyme fails, methylmalonic acid rises. That is why this marker catches a real deficiency even when blood B12 looks normal.
Where it fits
Vitamin B12 is a move in 5 protocols. Each one opens the plan it sits in.
What people say
Here is what doctors, influencers and men online say about Vitamin B12, word for word.
Experts
Clinicians, authorities
“Most cases of vitamin B12 and folate deficiency can be easily treated with injections or tablets to replace the missing vitamins.”
“The few investigations that have been conducted suggest that supplementing in the absence of a deficiency has no effect on fatigue.”
“But there is little evidence that B12 shots boost energy, weight loss or performance in people whose B12 levels are already normal.”
Gurus
Podcasts, channels, influencers
“It is high time we start looking at nutritional factors like B12 when it comes to mental health care.”
“Getting enough vitamin B12 is absolutely nonnegotiable for those centering their diets around plant-based foods.”
“There are no known excess/toxicity symptoms from supplements or food. Since only a small amount is absorbed via the oral route, potential for toxicity is low.”
Regular people
Forums, reviews, comments
“My symptoms were dismissed as "peri-menopausal", until I could hardly drag myself about. Then I had a blood test and started on the B12 jabs.”
“I increasingly find that I am dependent on the B12 for energy, mood, and weight maintenance. I can tell when my levels are low without a calendar”
“According to this article, logically all vegetarians should have neuropathy and severe symptoms. My whole family and forefathers have been vegetarians for thousands of years, one of most healthy and happy people on earth.”
The studies
Every study behind this page.
- Vitamin B12 deficiencyPubMed, PMID 28660890
- Mechanistic Link between Vitamin B12 and Alzheimer's DiseasePubMed, PMID 35053277
- Effects of Vitamin B12 Supplementation on Cognitive Function, Depressive Symptoms, and Fatigue: A Systematic Review, Meta-Analysis, and Meta-RegressionPubMed, PMID 33809274
- Efficacy of different routes of vitamin B12 supplementation for the treatment of patients with vitamin B12 deficiency: A systematic review and network meta-analysisPubMed, PMID 38231320
- B vitamins and prevention of cognitive decline and incident dementia: a systematic review and meta-analysisPubMed, PMID 34432056
- A systematic review and meta-analysis of functional vitamin B12 status among adult vegansPubMed, PMID 39373282
- Vitamin B-12 and the Gastrointestinal Microbiome: A Systematic ReviewPubMed, PMID 34612492
- Registered trial NCT07029698Trial registry
- Registered trial NCT05785585Trial registry
- Registered trial NCT07312435Trial registry
- Registered trial NCT06347315Trial registry
Words on this page
- PMID
- A study's ID number in PubMed, the public index of medical research.
Skip the energy shot. Get tested, and ask for methylmalonic acid, not just B12.
Emergency: call 911.
I am not a doctor. This is not medical advice. This is self-education. Talk to a physician who has your history before you change anything.