 [ Symptoms ] can b 12 cause leg cramps  since my husband started taking b 12 he has been getting severe leg cramps [ Disease ] i do not know why your husband it getting leg cramps there can be dozens of reasons but i can tell you that vitamin b12 does not cause them he will need to discuss this issue with his medical provider to determine a cause and a solution remember that men can be stubborn about getting medical care so your encouragement is very important i can not speak to the science or the research but i did not have leg cramp problems until i started taking b 12 i stopped taking it and have not had any leg cramp problems since your husband is not alone in having a similar experience