Mechanism of Action
Vitamin B12 acts as a cofactor for two essential enzymes. The first, methionine synthase, catalyzes the reconversion of homocysteine to methionine in the cytoplasm. This reaction simultaneously regenerates S-adenosylmethionine (SAM), the body's primary methyl group donor. SAM is involved in DNA methylation, neurotransmitter synthesis and creatine production.
The second enzyme, methylmalonyl-CoA mutase, operates within the mitochondria, the cell's energy powerhouses. It converts methylmalonyl-CoA to succinyl-CoA, a fuel for the Krebs cycle. This cycle is the central pathway for energy production. B12 insufficiency causes methylmalonic acid to accumulate, an early functional marker of inadequate status.
In the nervous system, B12 participates in myelin synthesis (the protective sheath around nerve fibers). Maintaining this sheath determines nerve conduction speed and the preservation of cognitive functions with age.
Key Benefits
- Strong
More day-to-day energy: vitamin B12 contributes to normal energy-yielding metabolism, serving as a cofactor for mitochondrial energy production via the Krebs cycle.
- Strong
A better-regulated homocysteine level: vitamin B12 contributes to normal homocysteine metabolism, an amino acid whose excess is associated with cardiovascular risk. A meta-analysis of 72 studies links a 3 µmol/L reduction in homocysteine to a 16% decrease in ischemic heart disease risk.
- Strong
A better-maintained nervous system: vitamin B12 contributes to normal functioning of the nervous system. It takes part in the synthesis of myelin, the sheath that insulates nerve fibers, and in maintaining nerve conduction.
- Strong
Well-renewed blood: vitamin B12 contributes to normal red blood cell formation, the cells that carry oxygen. This role is documented by data on erythrocyte maturation.
- Strong
Better mental balance: vitamin B12 contributes to normal psychological function. This effect draws on its role in the synthesis of neurotransmitters, the brain's chemical messengers, and in cerebral methylation.
- Strong
Less fatigue: vitamin B12 contributes to the reduction of tiredness and fatigue. This benefit stems from its involvement in cellular energy production and red blood cell formation.
- Moderate
Slower brain aging: the VITACOG clinical trial followed subjects with mild cognitive decline. B vitamin supplementation (including B12) cut the rate of brain atrophy by 30%, and by up to 53% when homocysteine exceeded 13 µmol/L.
Dosage & Forms
Three forms of vitamin B12 dominate the supplementation market. Cyanocobalamin, the most widespread synthetic form, requires a two-step hepatic conversion to become active. Adenosylcobalamin (dibencozide) is the mitochondrial coenzyme form, used by methylmalonyl-CoA mutase. Methylcobalamin is the cytoplasmic coenzyme form, directly mobilized by methionine synthase.
Singular selects methylcobalamin. The formula offers three calibration tiers: 250 µg (low tier), 1,000 µg (intermediate tier) and 1,500 µg (high tier), adjusted according to the biological profile.
The European nutritional reference intake is set at 2.5 µg per day. Supplementation doses are deliberately higher. Intestinal B12 absorption is limited by intrinsic factor receptor saturation. Beyond this threshold, only a passive absorption rate of about 1% remains.
In the Singular Formula
Inclusion rationale
Vitamin B12 contributes to normal energy metabolism, to the normal functioning of the nervous system, to normal homocysteine metabolism, to normal psychological functions, to normal red blood cell formation and to the reduction of tiredness and fatigue. A unique vitamin among all: it contains cobalt in its corrin ring, is exclusively synthesized by microorganisms, and its absorption requires a complex mechanism involving gastric intrinsic factor. The prevalence of B12 insufficiency increases significantly with age, affecting up to 20% of people over 60, due to the progressive decrease in gastric acid and intrinsic factor production. Vegan diets imperatively require supplementation. In the formula, B12 participates in the methylation cycle alongside TMG, vitamin B9 (5-MTHF) and vitamin B6 (P-5-P), together ensuring efficient remethylation of homocysteine to methionine. The methylcobalamin form selected is one of the two active coenzyme forms of B12: the one the body uses directly in the cellular cytoplasm, without prior hepatic conversion.
Selected form
Vitamin B12 as methylcobalamin, a coenzyme naturally present in the body. Unlike cyanocobalamin (the classic synthetic form), methylcobalamin requires no hepatic conversion to become active. It participates directly in the methionine cycle and homocysteine metabolism. Vitamin B12 contributes to normal energy-yielding metabolism, normal red blood cell formation and normal nervous system function. Quality: vegan, non-GMO.
Formula dosage
0 to 1,500 µg.
Synergies in the formula
Safety & Precautions
Vitamin B12 has a favorable safety profile. No tolerable upper intake level has been defined by European authorities due to the absence of documented toxicity, even at high doses. Absorption is self-limited by gastric intrinsic factor capacity.
Supplementation is not recommended in cases of known hypersensitivity to cobalt or cobalamins. Certain drug interactions deserve attention: metformin, proton pump inhibitors and H2 receptor antagonists can reduce B12 absorption. Individuals taking these medications benefit from regular monitoring of their status.
Pregnant and breastfeeding women can consume vitamin B12 within recommended intakes. Medical advice is recommended before any high-dose supplementation.
Scientific Studies
| Authors | Year | Type | Journal | |
|---|---|---|---|---|
| Clarke R et al. | 2014 | Meta-analysis | American Journal of Clinical Nutrition | View on PubMed |
Effects of homocysteine lowering with B vitamins on cognitive aging: meta-analysis of 11 trials with cognitive data on 22,000 individuals Meta-analysis of 11 controlled trials involving 22,000 individuals, evaluating the effect of B vitamin supplementation on age-related cognitive decline. | ||||
| Smith AD et al. | 2010 | Randomised Controlled Trial | PLoS ONE | View on PubMed |
Homocysteine-lowering by B vitamins slows the rate of accelerated brain atrophy in mild cognitive impairment: a randomized controlled trial The VITACOG trial showed that supplementation with vitamins B9, B12 and B6 reduces brain atrophy rate by 30% in elderly subjects with mild cognitive impairment. | ||||
| Wald DS et al. | 2002 | Meta-analysis | BMJ | View on PubMed |
Homocysteine and cardiovascular disease: evidence on causality from a meta-analysis Meta-analysis combining 72 genetic and 20 prospective studies establishing that a 3 µmol/L reduction in homocysteine is associated with a 16% decrease in ischemic heart disease risk and 24% decrease in stroke risk. | ||||
| Green R et al. | 2017 | Systematic Review | Nature Reviews Disease Primers | View on PubMed |
Vitamin B12 deficiency Landmark review covering the epidemiology, pathophysiological mechanisms, diagnosis and management of vitamin B12 insufficiency. | ||||
| Douaud G et al. | 2013 | Randomised Controlled Trial | Proceedings of the National Academy of Sciences | View on PubMed |
Preventing Alzheimer's disease-related gray matter atrophy by B-vitamin treatment Follow-up of the VITACOG trial showing that B vitamin supplementation slows gray matter atrophy in brain regions vulnerable to age-related neurodegeneration. | ||||
| Porter K et al. | 2016 | Systematic Review | Nutrients | View on PubMed |
Causes, Consequences and Public Health Implications of Low B-Vitamin Status in Ageing Review of the causes and consequences of low B-vitamin status in aging populations, including absorption factors and insufficiency prevalence. | ||||