Does Mark Hyman recommend Vitamin B12?
Mark Hyman recommends Vitamin B12 in some contexts, but has also raised cautions.
Published research rates it strong evidence. Of Mark Hyman's 26 tracked claims, 12 are supported or partially supported by studies on PubMed.
Evidence last reviewed May 2026
Mark Hyman on Vitamin B12 — 26 claims
“the ones that are really causing Havoc are you know deficiencies and you know the methylation nutrient it's like the B vitamins folate B6 B12 deficiencies”
Deficiencies in methylation nutrients including B12, folate, and B6 are among the most common and impactful nutrient deficiencies causing problems in the country.
“We check your level of B vitamins like homoyine and methylonic acid which measure B12, folate, B6 effectiveness.”
Methylmalonic acid and homocysteine can be tested to measure the effectiveness of B12, folate, and B6, as part of a 'test, don't guess' approach to identifying nutrient deficiencies.
“a B12 shot and they're on a different path”
Giving a B12 shot to patients with low-normal B12 levels who have severe depression can put them on a different (improved) path.
“the ones that are really causing Havoc are you know deficiencies and you know the methylation nutrient it's like the B vitamins folate B6 B12 deficiencies”
Deficiencies in methylation nutrients including B12, folate, and B6 are among the most common and impactful nutrient deficiencies causing problems in the country.
The published research confirms that B12, folate, and B6 deficiencies are clinically relevant and relatively common. PMID 40961307 notes B12 deficiency occurs in approximately 2-3% of U.S. adults with…
“We check your level of B vitamins like homoyine and methylonic acid which measure B12, folate, B6 effectiveness.”
Methylmalonic acid and homocysteine can be tested to measure the effectiveness of B12, folate, and B6, as part of a 'test, don't guess' approach to identifying nutrient deficiencies.
The published research indirectly supports the use of methylmalonic acid (MMA) and homocysteine as functional biomarkers for B12 and folate status. PMID 27916823 (review on B12 among vegetarians) and…
“a B12 shot and they're on a different path”
Giving a B12 shot to patients with low-normal B12 levels who have severe depression can put them on a different (improved) path.
The meta-analysis (PMID: 33809274) directly addresses B12 supplementation for depressive symptoms via RCTs and concludes that effectiveness in cases without overt deficiency or advanced neurological d…
“you want to make sure that you reduce your uh drugs if you can or switch to different drugs or are not that are not depleting the the nutrients or that you actually take the nutrients as a replacement”
If taking nutrient-depleting drugs such as acid blockers, patients should either switch drugs or take the depleted nutrients (including B12) as replacement.
“you want to make sure that you reduce your uh drugs if you can or switch to different drugs or are not that are not depleting the the nutrients or that you actually take the nutrients as a replacement”
If taking nutrient-depleting drugs such as acid blockers, patients should either switch drugs or take the depleted nutrients (including B12) as replacement.
The research provides clear support for the premise that certain medications (notably metformin and proton pump inhibitors/acid blockers) deplete B12 and that deficiency causes clinically significant…
“some of the nutritional deficiencies that are pretty common that any family doc could do would be vitamin B12 and d”
Vitamin B12 deficiency is a common nutritional deficiency seen in patients with depression that is modifiable.
The claim that B12 deficiency is common in depression patients and modifiable is partially supported. PMID 40961307 confirms B12 deficiency symptoms include depression and brain fog, and PMID 35743024…
“some of the nutritional deficiencies that are pretty common that any family doc could do would be vitamin B12 and d”
Vitamin B12 deficiency is a common nutritional deficiency seen in patients with depression that is modifiable.
“if you taking an acid blocking drug you're going to prevent B12 absorption and even magnesium and and zinc absorption”
Acid-blocking drugs prevent B12 absorption.
The claim that acid-blocking drugs (proton pump inhibitors) prevent B12 absorption is partially supported by the available literature. PMID 40961307 (a review on B12 deficiency) explicitly lists proto…
“It inhibits B12 absorption which is critical for so many functions that can cause depression, dementia, neurologic issues. People don't know this”
Long-term use of proton pump inhibitors (PPIs) inhibits B12 absorption, which is critical for many functions, and can cause depression, dementia, and neurologic issues.
The claim that PPIs inhibit B12 absorption is directly supported by PMID 40961307, which explicitly lists PPIs as a risk factor for B12 deficiency alongside other medications. The same review confirms…
“vitamin B12 is a pet peeve of mind because our normal range the lab slips might say 220 to 1100 and nobody feels well with a level of 220 so times we've treated people with severe depression that we're told by their PCP they have normal B12”
The conventional lab normal range for B12 (220–1100) is misleading because nobody feels well at a level of 220, and patients with severe depression have been told they have normal B12 when they do not.
“if you taking an acid blocking drug you're going to prevent B12 absorption and even magnesium and and zinc absorption”
Acid-blocking drugs prevent B12 absorption.
“vitamin B12 is a pet peeve of mind because our normal range the lab slips might say 220 to 1100 and nobody feels well with a level of 220 so times we've treated people with severe depression that we're told by their PCP they have normal B12”
The conventional lab normal range for B12 (220–1100) is misleading because nobody feels well at a level of 220, and patients with severe depression have been told they have normal B12 when they do not.
The published research supports that B12 deficiency symptoms—including fatigue, depression, and cognitive impairment—can occur across a range of B12 levels, and that current diagnostic thresholds may…
“It inhibits B12 absorption which is critical for so many functions that can cause depression, dementia, neurologic issues. People don't know this”
Long-term use of proton pump inhibitors (PPIs) inhibits B12 absorption, which is critical for many functions, and can cause depression, dementia, and neurologic issues.
“rather than just taking a drug to suppress stomach acid which we desperately need to digest our food to absorb minerals to absorb B12 to digest protein”
Stomach acid is needed to absorb B12, and drugs that suppress stomach acid interfere with this absorption.
The claim that stomach acid is needed for B12 absorption and that acid-suppressing drugs interfere with this process is a well-established physiological mechanism. PMID 40961307 (a review on B12 defic…
“We check your level of B vitamins like homoyine and methylonic acid which measure B12, folate, B6 effectiveness.”
Measuring methylmalonic acid and homocysteine can assess B12 effectiveness as part of a functional medicine workup.
The provided literature indirectly supports the use of methylmalonic acid (MMA) and homocysteine as functional markers of B12 status. The review on B12 deficiency (PMID: 40961307) notes that standard…
“you also need a lot of nutrients to metabolize your toxins things like folate zinc selenium magnesium manganes you need all the methylating B vitamins folate B12 B6 um and you need these are all co-actors that basically power all those detox enzymes that are processing all the toxins”
B12, along with folate and B6, is needed as a co-factor to power detox enzymes that process toxins.
The research base provided largely addresses B12 deficiency symptoms, supplementation outcomes, and dietary considerations rather than directly testing the claim that B12, folate, and B6 act as co-fac…
“the critical supports for this nerve growth factor brain derived neurotrophic Factor B12 all these things it takes as you know it takes a lot to keep a brain functional”
B12 is one of the critical supports needed to keep the brain functional, particularly in atrophic-type neurodegeneration.
Other supplements Mark Hyman discusses
Claims are extracted from publicly available podcasts and videos, attributed to their source, and compared against PubMed research. This is educational information only — consult a healthcare provider before starting any supplement.
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