The Best Vitamins For Tiredness & Lack Of Energy, According To RDs

If you, like more than one-third of American adults1, struggle to get enough sleep on a daily basis, you've likely experienced your fair share of sluggish days. You know the ones: days when you feel downright exhausted and lethargic, as if your brain and body are moving glacially. But, here's the thing: You don't necessarily have to have sleep health concerns to deal with these types of days regularly. In fact, poor shut-eye is only one reason for tiredness and lack of energy. Another cause of suboptimal energy levels? Lacking certain vitamins and minerals. 

"Nutritional deficiencies can cause low energy and occasional fatigue because your body's trillions of cells rely on vitamins and minerals to generate energy," explains Samantha Ferguson, M.S., R.D., L.D., a registered dietitian and dietitian nutrition coach at Wellory. "Different factors such as stress, exercise, alcohol, environment, and undereating can deplete your vitamin and mineral stores, so it's important to ensure you are replenishing these stores to feel your best and most energized." 

The first way to do just that is by eating a well-rounded, balanced diet that's rich in whole foods, Ferguson says. "It's important to try to get these vitamins and minerals from food first, as food's a complex source of vitamins, minerals, and phytochemicals that all work synergistically to provide the most bioavailable forms of those vitamins and minerals."

But if your diet is up to snuff and you're still struggling with tiredness, adding supplements to your routine might help resolve any shortages of nutrients and, in turn, boost your energy as needed. The only way to truly know whether or not your levels of certain nutrients are low, however, is to have them tested. So, before popping any capsules or mixing any powders, it's a good idea to consult your general health care provider, who can administer a blood test to determine any deficiencies and recommend the ideal dosage and product based on your test results and overall health. 

Along with the seven other B vitamins, vitamin B12 (aka cobalamin, or methylcobalamin in its activated form) works to "break down the foods we eat and turn them into energy,"* says May Zhu, RDN, LDN, registered dietitian nutritionist and founder of Nutrition Happens. This energy is in the form of adenosine triphosphate (ATP), which is essentially the main energy currency that keeps your cells (and whole body) going.

Vitamin B12 also supports the formation of red blood cells, adds Zhu.* This is key for helping the body get enough oxygen-rich blood and maintain a sufficient amount of red blood cells. With suboptimal oxygenated blood or red blood cells, you may feel tired and in need of adequate energy.

While the highest concentrations of B12 are found in animal products—such as meat, eggs, seafood, and dairy—many non-animal foods are also fortified with the nutrient (e.g., breakfast cereals and nutritional yeasts). Still, reaching optimal levels of vitamin B12 through diet alone can be a challenge for plant-based eaters, which is why the National Academies recommends vegans and vegetarians consider coupling any vitamin-B12-rich eats with supplementation to meet the recommended dietary amount (RDA) of 2.4 micrograms per day for adults. 

Another member of the B vitamin complex, vitamin B6 (pyridoxal 5-phosphate in its active form) can increase the production and release of a handful of energizing neurotransmitters—including dopamine, norepinephrine, and serotonin2, according to a 2008 Cells scientific review. "The nutrient also plays an important role in your metabolism and the release of energy from food by converting glycogen (the stored form of carbohydrates) into glucose (the main energy source)," Ferguson explains.  

Vitamin D not only boosts mood and supports a healthy immune system, but it can also help keep your energy levels stable, says Valerie Agyeman, R.D., dietitian and host of the Flourish Heights podcast. 

"In fact, low energy and occasional fatigue are common in people with vitamin D deficiency," Agyeman explains. That might be because vitamin D helps mitochondria (the powerhouses of the cell that create energy) use oxygen, thus helping to provide energy to many body parts—including muscles, she adds. 

Unless you live near the equator and spend lots of time outdoors, you're likely not getting enough daily vitamin D. Just take it from research, which has found that 29% of American adults4 are vitamin D deficient and 41% are vitamin D insufficient. 

Considering it's involved in over 300 enzymatic reactions5 in the body (per a 2017 Scientifica review), it might not come as a shock to learn that magnesium, in Agyeman's words, is a key player in energy creation: "Magnesium helps convert food into energy and is needed for the production of ATP," she explains. (Remember, ATP is the fundamental unit of energy within cells.)

So, it makes sense that without ample amounts of magnesium in your body, you're more likely to feel drained. After all, your body doesn't have enough of what it needs to make the compound that powers your cells.

The good news? Magnesium can be found in a variety of foods, including dairy products, legumes, seeds, whole grains, and leafy vegetables. The not-so-good news? It's estimated that the standard U.S. diet contains only about 50% of the RDA for magnesium, which is 400-420 milligrams for men and 310-320 milligrams for women. 

Iron is responsible for making hemoglobin, a protein in red blood cells that helps transport oxygen throughout the body. "When the body is low on oxygen, the tissues, muscles, and cells will lack oxygenation and blood flow, causing you to feel more tired," Ferguson explains. 

Packing your plate with iron-rich foods—such as lean meats, seafood, poultry, fortified products (e.g., cereals and breads), beans, and nuts—can help you maintain healthy iron levels and steer clear of any iron-related lulls in energy. To boost absorption of this critical mineral, consume iron-rich foods alongside vitamin-C-rich foods (like citrus fruits, red peppers, broccoli, and tomatoes), Ferguson recommends. 

There are several reasons you might experience tiredness, one of which is falling short on key nutrients. "There are some vitamins that may have a direct effect with your energy levels, and it may be noticeable—especially if you're already deficient. Others may contribute toward certain processes that help create and maintain energy," Agyeman shares. 

Iron, for example, is responsible for making hemoglobin, a protein in red blood cells that helps transport oxygen throughout the body. When you don't have enough iron, your body doesn't receive enough oxygen-rich blood and, as a result, you can start to feel tired. Other nutrients that can impact your energy levels include vitamin B12, vitamin B6, vitamin D, and magnesium. As such, these nutrients are some of the best vitamins for tiredness and lack of energy.