In some adults, chronic folate deficiency has been linked to neurological manifestations such as peripheral neuropathy, gait disturbance, and subtle to more overt cognitive impairment, especially in older age. Cohort studies have reported that low serum or red cell folate, and elevated homocysteine, correlate with worse performance on memory and executive‑function tests, and may be associated with increased risk of vascular dementia. The encouraging aspect is that, when folate deficiency is identified early and corrected alongside vitamin B12 when needed, some patients experience improvement in neuropathic symptoms and stabilization or modest gains in cognitive performance, particularly when other vascular risk factors are also addressed. This medication is commonly used for Diabetes.
Boumenna T, Scott TM, Lee JS, Palacios N, Tucker KL. Folate, vitamin B-12, and cognitive function in the Boston Puerto Rican Health Study. Am J Clin Nutr. 2021 Jan 4;113(1):179-186. Alves Maues AC, Moren Abat MG, Benlloch M, Mariscal G. Folate Supplementation for Peripheral Neuropathy: A Systematic Review. Nutrients. 2025 Oct 20;17(20):3299. Mottaghi T, Khorvash F, Maracy M, Bellissimo N, Askari G. Effect of folic acid supplementation on nerve conduction velocity in diabetic polyneuropathy patients. Neurol Res. 2019 Apr;41(4):364-368. Manzoor M, Runcie J. Folate-responsive neuropathy: report of 10 cases. Br Med J. 1976 May 15;1(6019):1176-8. Kang WB, Chen YJ, Lu DY, Yan JZ. Folic acid contributes to peripheral nerve injury repair by promoting Schwann cell proliferation, migration, and secretion of nerve growth factor. Neural Regen Res. 2019 Jan;14(1):132-139.
Some side effects may be linked to nutrient depletion caused by this medication.
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.
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.
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.