The Best Time to Take B-Complex Vitamins

Many people take B-complex supplements for energy—but are you taking them at the right time? Yup, when you take a supplement can play a significant role in how it impacts your body and health. 

We interviewed three experts—two dietitians and one pharmacist—to share the ins and outs of when to take a B-complex vitamin and other factors that affect their absorption. Turns out that taking your B-complex vitamins at the right time can help you reap the most benefits and prevent unpleasant side effects, such as stomach upset or restlessness. 

Why People Take B-Complex Vitamins

B-complex vitamins are a group of eight vitamins required for energy production in the body. They also help synthesize DNA and RNA, as well as neurotransmitters. They’re water soluble, so your body doesn’t store them long-term. This makes it even more important to consume enough B-complex vitamins daily.

If you have higher B-vitamin needs, don’t consume enough B vitamins from food, take certain medications or have a malabsorption issue, you may develop a deficiency in one or more B vitamins. Since there are eight different types of B vitamins, a deficiency can present in various ways. Some clues that you might be deficient in one or more B vitamins are fatigue, eye irritation, anemia, confusion, low mood, stomach upset, insomnia, skin inflammation and tingling in your hands and feet.

Certain groups of people are most likely to benefit from incorporating a B-complex vitamin into their wellness regimen. “Vegans and vegetarians may fall short on B12, or those suffering from chronic stress tend to burn through B vitamins more quickly,” says Caroline Thomason, RD, CDCES. “Plus, certain medications, like metformin, oral contraceptives, and stomach acid reducers, can deplete B levels over time. Older adults are also more likely to have poor B12 absorption due to reduced stomach acid,” she adds. You may also need a B-complex vitamin if you have a digestive issue like celiac or Crohn’s disease that hinders the absorption of B vitamins. 

Optimal Timing for B-Vitamins Intake

All three experts we interviewed recommend taking your B vitamins in the morning. “B vitamins are deeply involved in energy metabolism, so taking them early helps your body convert food into fuel during the hours you’re most active,” says Jennifer Pallian, RD. 

Ideally, pair your vitamin with food for better absorption and a lower risk of stomach upset. “Eating first helps improve absorption and prevents any mild nausea some people experience with B vitamins like niacin,” says Thomason.

Even if you can’t take your B vitamins first thing in the morning, experts recommend taking them as early as you can. “It’s best to avoid taking a B-vitamin complex at night, as certain B vitamins such as vitamin B12 (methylcobalamin) may have a mild stimulatory effect,” says Adam Jameson, clinical pharmacist.

Factors Affecting B-Vitamins Absorption 

Those That Enhance It

B vitamins are water-soluble, so technically you can take them with or without food. However, taking them with food may help prevent digestive upset and improve absorption. “Taking a B-complex with a meal (preferably breakfast) can enhance absorption, especially for B1, B2 and B6, which are better absorbed when the stomach is producing digestive acids and enzymes,” says Jameson.

The form of B vitamin you take also impacts its absorption. Certain forms are more bioavailable—a fancy way of saying your body can absorb them more efficiently. For example, “Methylcobalamin is a more bioavailable form of vitamin B12 than cyanocobalamin, and similarly, 5-MTHF (methylfolate) is an activated form of folate (vitamin B9),” says Jameson.

Those That Prevent It

Unfortunately, there are a lot of things that can hinder your body’s absorption of B vitamins. “Several things can impair absorption, including alcohol, smoking, chronic stress and malabsorptive digestive disorders like IBS,” says Thomason. “Low stomach acid, which is common with age or certain medications, also reduces B12 absorption. And drugs like metformin, proton pump inhibitors and hormonal contraceptives can all interfere with how your body uses or stores B vitamins,” she adds. If you’re at risk for poor absorption of B vitamins, you may need a B-vitamin supplement to meet your nutritional needs. A healthcare provider can offer individualized guidance on the best way to prevent or correct a deficiency.

Precautions and Potential Side Effects

B vitamins are water-soluble, so there’s a low risk of toxicity. You typically excrete any extra B vitamins your body doesn’t need in your urine. This can cause your urine to turn bright yellow. It’s nothing dangerous, but something to be aware of.

In some cases, taking excessive B vitamins can cause side effects, including itching, skin rash, trouble breathing, flushing, sweating, weakness, digestive issues, restlessness and headaches. If you experience any unusual health problems after taking a B vitamin, consult your healthcare provider immediately.

Our Expert Take

B vitamins may be worth taking if you follow a vegetarian or vegan diet, are over 65 years old or take certain medications that can reduce B-vitamin absorption. Still, consult with your healthcare provider before starting a new supplement to ensure it’s safe and worthwhile for you. If you are taking a B-complex vitamin, experts recommend taking it in the morning to reap the energy-producing benefits and prevent it from keeping you up at night. You may find that taking it with food helps prevent it from upsetting your stomach, so try eating it with your breakfast.