Vitamin KDoes vitamin K2 help with night-time leg cramps?
Updated 3 Nov 2026
Short answer
One trial found that it does, in older adults. In China, 199 adults aged 65 and older with night-time leg cramps took 180 µg of MK-7 or a placebo every day for 8 weeks. With MK-7, cramps fell from 2.6 to 0.96 a week. With placebo, they went from 2.71 to 3.63 a week. Cramps were also shorter and less painful with MK-7, and no side effects of MK-7 were found.[1]
In 2025 the journal retracted the first version of this paper and replaced it with a corrected version.[1] A small crossover trial in people on dialysis (39 completed it) also found fewer, shorter and milder cramps with 360 µg of vitamin K2 a day.[2]
Sources (2)
- Vitamin K2 in Managing Nocturnal Leg Cramps: A Randomized Clinical Trial. Tan J, Zhu R, Li Y, Wang L, Liao S, Cheng L, et al. JAMA Intern Med, 2024. PMID 39466236
- Vitamin K2 as a potential therapeutic candidate for the prevention of muscle cramps in hemodialysis patients: A prospective multicenter, randomized, controlled, crossover pilot trial. Xu D, Yang A, Ren R, Shan Z, Li YM, Tan J Nutrition, 2022. PMID 35203045
More about vitamin k
What is vitamin K?Which foods contain vitamin K?What is vitamin K used for?Who is at risk of vitamin K deficiency?Is vitamin K safe?Why do newborn babies get vitamin K?For education; not medical advice. Talk to a doctor before you start, stop or change a supplement.