Vitamin B12 deficiency is strongly associated with cognitive impairment, including problems with memory, attention, and executive function, and is considered a reversible cause of dementia when caught early. Low or borderline B12 levels are more common in older adults, particularly those with atrophic gastritis, long-term use of acid-suppressing medications, or vegetarian/vegan diets, and studies show that deficient individuals often perform worse on cognitive tests than those with adequate status. Clinically, correcting B12 deficiency can lead to measurable improvements in cognition and mood in some patients, which is why B12 levels are routinely checked in the evaluation of cognitive decline and suspected dementia. This medication is commonly used for Diabetes.
Jatoi S, Hafeez A, Riaz SU, Ali A, Ghauri MI, Zehra M. Low Vitamin B12 Levels: An Underestimated Cause Of Minimal Cognitive Impairment And Dementia. Cureus. 2020 Feb 13;12(2):e6976. Ueno A, Hamano T, Nagata M, Yamaguchi T, Endo Y, Enomoto S, Kimura H, Ikawa M, Yamamura O, Yamanaka D, Kimura Y, Nakamoto Y, Nishiyama Y. Association of vitamin B12 deficiency in a dementia cohort with hippocampal atrophy on MRI. J Prev Alzheimers Dis. 2025 Sep;12(8):100265. Issac TG, Soundarya S, Christopher R, Chandra SR. Vitamin B12 deficiency: an important reversible co-morbidity in neuropsychiatric manifestations. Indian J Psychol Med. 2015 Jan-Mar;37(1):26-9. Moore E, Mander A, Ames D, Carne R, Sanders K, Watters D. Cognitive impairment and vitamin B12: a review. Int Psychogeriatr. 2012 Apr;24(4):541-56.
Some side effects may be linked to nutrient depletion caused by this medication.
Long term treatment with Biguanides, such as Metformin or Metformin combinations with other drugs, are found in research to reduce vitamin B12 absorption due to it hindering the activity of a calcium-dependent mechanism. Insufficient levels of vitamin B12 can lead to higher circulating homocysteine levels and the elevated risk of neurological problems and cardiovascular diseases.
Biguanide (anti-diabetic) drugs have been found in scientific evidence to decrease serum levels of coenzyme Q10. Type 2 diabetes can increase oxidative stress in the body, weakening its defenses and potentially harming cells. CoQ10, a powerful antioxidant, plays a crucial role in protecting cells from this damage. CoQ10 supplementation may help restore these levels, potentially improving mitochondrial function and protecting the kidneys from damage.
Research has shown that anti-diabetic Biguanide drugs may reduce folic acid absorption. Folic acid is a powerful antioxidant and low levels make the body more susceptible to oxidative stress, which can damage enzymes involved in homocysteine metabolism, and subsequently increase its accumulation. Elevated levels of homocysteine (hyperhomocysteinemia) are a risk factor for various health problems including cardiovascular diseases, neurological problems, osteoporosis, and vision problems.
Biguanides, such as Metformin or Metformin combinations with other drugs, may contribute to reduced levels of thiamine (vitamin B1) in end-stage renal failure patients. Research has found metformin encephalopathy present in patients on hemodialysis for end-stage diabetic renal failure (ESRD). Patients with ESRD should consider having thiamine (vitamin B1) status monitored and supplementing with thiamine when levels are insufficient or deficient.