Can b12 or folic acid deficiency cause hair thinning and hair loss? I am a 57 year old female and have had tingling in hands a feet, mouth sores that come and go in a couple of days, a lot of hair thinning, low energy and my doctor tested my mch and it came back as 33.5. I haven t had my follow visit or test on b12 or folic acid yet. I also have Crohns and take methotrexate injection. I only take a one a day vitamin so after getting the results about my mch it make sense that I could have anemia. But can it also affect my hair growth?