How Much Vitamin B12 Should You Take: Overdose, Side Effects and More

Vitamin B12 or cobalamin is essential because it supports the nervous system, produces red blood cells and helps make DNA. Because this vitamin is so important, people sometimes choose to supplement it. Could they risk an overdose?

Vitamin B12 is a water-soluble vitamin. It can dissolve quickly in water, being absorbed by the body. So, even if you overdose, your body can only absorb a fraction of the B12 supplements, according to medical research.

Here is what you need to know.

Can You Overdose on Vitamin B12?

According to Natalie Allen, RD, a clinical assistant professor of biomedical at Missouri State University, there’s no such thing as overdosing on vitamin B12. Previous studies indicated no side health effects when taking more B12, either through supplements and, of course, food.

As previously mentioned, even in high doses, our bodies can only absorb a part of vitamin B12 supplements. For instance, if you choose to take a 500mcg oral B12 supplement, your body will absorb just  10mcg. However, it is possible to have enhanced B12 levels in a blood test, and that’s no good at all.

Increased levels of vitamin B12 might indicate various health issues, such as:

• Diabetes;
• Liver disease;
• Cancer;
• Impaired kidney function.

Remember to check your B12 level and discuss with your doctor to run more tests to find out the underlying cause.

Side Effects: Should We Worry?

According to specialists, the side effects of B12 supplementation are pretty rare. It is possible to occur with B12 injections and not pills. But why is it different with B12 injections?

The reason is simple. The absorption rate from injections is much higher than it is from taking pills. The only side effects of vitamin B12 shots are:

• Nausea;
• Fatigue;
• Dizziness;
• Diarrhoea;
• Fatigue;
• Headache;
• A tingling feeling in feet or hands.

Your Daily B12 Intake

The recommended dose of B12/day is the same for both women and men but varies by age, as follows:

• 0 to 6 months: 0.4mcg;
• 7 to 12 months: 0.5mcg;
• 1 to 3 years: 0.9mcg;
• 4 to 8 years: 1.2mcg;
• 9 to 13 years: 1.8mcg;
• 14+ years: 2.4mcg;
• Pregnant women: 2.6mcg;
• Breastfeeding women: 2.8mcg.