Vitamin B12 supplements will only improve symptoms such as tiredness and lack of energy if they are caused by low vitamin B12 levels. It may take a few weeks before your vitamin B12 levels and symptoms (such as extreme tiredness or lack of energy) start to improve.
How Long Does It Take for B12 to Work? You may start feeling the effects of vitamin B12 within 3-4 weeks of taking a supplement consistently. However, if you have a severe B12 deficiency it can take six months or more to fully correct it.
So does vitamin B12 give you energy? While B12 doesn't directly provide energy, it does give the body the tools it needs to convert food molecules into energy. Getting the recommended daily amount of B12 can therefore help ensure that the body is able to make the energy it needs to do everything you need it to do.
Vitamin B12 is often used to improve cognitive function, depressive symptoms, and fatigue. In most cases, such complaints are not associated with overt vitamin B12 deficiency or advanced neurological disorders and the effectiveness of vitamin B12 supplementation in such cases is uncertain.
Constant fatigue is one of the main symptoms of a B12 deficiency, because when this vitamin is low, the body has fewer red blood cells. The primary job of those red blood cells is to transport oxygen from the lungs to other parts of the body. A lack of red blood cells translates to fatigue.
Once you begin treating your vitamin B12 deficiency, it can take up to six to 12 months to fully recover. It is also common to not experience any improvement during the first few months of treatment. If you can, it's a good idea to address what's causing the deficiency.
A lack of B12 may lead to depression, confusion, memory problems, and dementia. It also can affect your balance. B12 supplements are usually safe.
Key points about vitamin B12 deficiency anemia
Without enough red blood cells, your tissues and organs don't get enough oxygen. Without enough oxygen, your body can't work as well. Symptoms include weak muscles, numbness, trouble walking, nausea, weight loss, irritability, fatigue, and increased heart rate.
Lack of vitamin B12 in your diet: People who don't eat enough foods that naturally have vitamin B12 or don't eat foods fortified with vitamin B12 can develop vitamin B12 deficiency. Gastritis: Gastritis is inflammation of the stomach lining, and it's a common cause of vitamin B12 deficiency.
Diet. Some people can develop a vitamin B12 deficiency as a result of not getting enough vitamin B12 from their diet. A diet that includes meat, fish and dairy products usually provides enough vitamin B12, but people who do not regularly eat these foods can become deficient.
Around 50% to 98% of vitamin B12 is excreted from the body 48 hours after injection. Research shows that vitamin B12 has a half-life of 6 days in the blood, making it six days before the administered amount gets excreted from your body.
There is no risk of an overdose when taking large amounts of vitamin B-12 such as 1000 mcg, because it is a water-soluble vitamin. Meaning the body will use the amount that it needs then the excess will be excreted through urine.
Vitamin B-12 and other B vitamins play a role in producing brain chemicals that affect mood and other brain functions. Low levels of B-12 and other B vitamins such as vitamin B-6 and folate may be linked to depression.
Bananas also contain fibre and potassium. It helps manage blood pressure, reduce stress, and relieve constipation and ulcer problems. The fruit also helps regulate body temperature. Another fruit that is rich in vitamin B12 is blueberries.
Most healthy people who have a well-balanced diet do not need to worry much about vitamin B12 deficiency. However, for those at risk (such as those with celiac disease), measures of blood vitamin B12 levels and, in some cases, preventive therapy with vitamin B12 may be recommended.
Side effects of B12 are uncommon but may include: diarrhea. constipation.
Vitamin C (ascorbic acid) supplements.
Taking vitamin B-12 with vitamin C might reduce the available amount of vitamin B-12 in your body. To avoid this interaction, take vitamin C two or more hours after taking a vitamin B-12 supplement.
Fat-soluble and water-soluble vitamins
Some combinations should be avoided, even if they aren't inherently problematic. For example, although it's safe to take vitamin D with vitamin B12, it's not advisable, says Virgilio Sanchez, MD, a board certified family medicine physician at Conviva Care Center in Miami, Florida.
“The best time to take a multivitamin is with food so any fat can help with absorption. You can also drink a water-based beverage to wash it all down,” notes Dr. Perez-Gallardo. “But the drawback is that your body won't absorb the water-soluble vitamins as well as fat-soluble ones.”
Not getting enough vitamin B12 to the point of a deficiency can cause a variety of serious symptoms including depression, joint pain, and fatigue.
Vitamin B12 testing requires a blood sample, which is usually taken from your arm in a medical office, health clinic, hospital, or lab.
A B12 deficiency may also cause diarrhea, nausea, constipation, bloating, gas, and other gastrointestinal symptoms ( 2 , 19 ). These issues can affect both adults and children ( 2 , 20 ).