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Levonorgestrel

Levonorgestrel & Vitamin B12

Depletes Vitamin B12. This medication is commonly used for Contraception

Why Levonorgestrel affects Vitamin B12

Oral contraceptives (OCs) have been linked to a decrease in Vitamin B12 levels. Studies have shown a significant reduction in serum B12, the vitamin circulating in the blood, in women taking OCs for extended periods. One US study found a 40% decrease in B12 levels after five years of OC use. This decrease is concerning because vitamin B12 plays a crucial role in converting a form of folate (N-methyltetrahydrofolic acid) into its active form (tetrahydrofolic acid). This active folate is essential for healthy red blood cell production and other bodily functions. Due to the vital role of vitamin B12, supplementation when using OCs long-term should be considered.

Clinical Evidence

Lussana F, Zighetti ML, Bucciarelli P, Cugno M, Cattaneo M. Blood levels of homocysteine, folate, vitamin B6 and B12 in women using oral contraceptives compared to non-users. Thromb Res. 2003;112(1-2):37-41. Shikh EV, Makhova AA, Chemeris AV, Tormyshov IA. [Iatrogenic deficits of micronutrients]. Vopr Pitan. 2021;90(4):53-63. Russian. Palmery M, Saraceno A, Vaiarelli A, Carlomagno G. Oral contraceptives and changes in nutritional requirements. Eur Rev Med Pharmacol Sci. 2013 Jul;17(13):1804-13. PMID: 23852908. Young RC, Blass JP. Iatrogenic nutritional deficiencies. Annu Rev Nutr. 1982;2:201-27.

Recommended Replacement

Vitamin B12 Methylcobalamin0.2 mg

Related Health Impacts

  • Memory Loss & Mental Decline

    In older adults, low folate status has been associated with a higher risk of mild cognitive impairment (MCI) and faster cognitive decline over time, likely through effects on one‑carbon metabolism and homocysteine. Several longitudinal cohort studies have found that individuals with lower serum or red‑cell folate and higher homocysteine show steeper declines on memory and global cognition tests, and in some cohorts have a significantly higher incidence of MCI or dementia over follow‑up. The clinically important takeaway is that, when folate deficiency is detected and corrected (usually along with ensuring adequate vitamin B12), some patients demonstrate stabilization or modest improvement in cognitive performance, particularly when interventions are combined with aggressive management of vascular risk factors such as hypertension and diabetes.

Supplement Recommendation

Vitamin B12 Methylcobalamin by Pure Encapsulations0.2 mg

Other Nutrients Affected by Levonorgestrel

Next Steps
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