Fatigue is more than just a general feeling of tiredness, it’s reduced energy that could be a sign of a bigger issue such as a mood disorder or thyroid problem.

If you’ve seen your doctor and know a medical issue isn’t at play, you may want to try one or more of these supplements to address these common causes of fatigue.

Magnesium

Magnesium is involved in hundreds of reactions in the body and many experts believe most Americans aren’t getting adequate amounts of the important mineral.

One of the initial symptoms of a magnesium deficiency is fatigue; others include insomnia and irritability. Studies have also shown that magnesium helps to reduce symptoms of stress and promote a more restful sleep.

Most people’s diets don’t supply the average recommended daily amounts of magnesium – 310-320 milligrams for women and 400-420 milligrams for men – so experts recommend a daily supplement.

Try: Natural Vitality Natural Calm

L-theanine

L-theanine, an amino acid found in tea leaves, is known to boost levels of the neurotransmitter gamma-aminobutyric acid (GABA). GABA works in the brain to regulate mood and promote sleep and relaxation.

A randomized, double-blind, placebo-controlled trial studying the effects of l-theanine on boys with attention deficit hyperactivity disorder (ADHD) found that supplementing with l-theanine safely improved sleep quality when compared to a placebo.

The dosage used in the study was 400 milligrams per day.

Try: 

Order GABA with L-Theanine

Vitamin B12

If you have symptoms of weakness and fatigue, you could have a vitamin B12 deficiency.

Our bodies need B12 to synthesize red blood cells and DNA and to carry out lots of other important functions. Like most vitamins, our bodies can’t make B12 so we depend on diet and supplements to get the recommended 2.4 micrograms per day.

See also The Essential B Vitamins.

Food sources of B12 include meat, dairy and eggs, so vegans are at risk of a deficiency. B12 absorption can also be difficult for some people and becomes even harder as we age.

A good multivitamin or B-complex vitamin should do the trick.

Order Vitamin-B Complex

Rhodiola Rosea

Rhodiola Rosea has been studied extensively for its adaptogenic or stress-reducing properties. The supplement, also known as golden root, has been used in both traditional and modern medicine to fatigue and mood disorders.

In a study of 56 young, healthy physicians on night shift, rhodiola rosea was found to reduce symptoms of work-related fatigue.

The supplement has also been found to reduce post-exercise recovery time and enhance endurance in athletes.

Doses vary from study to study. For best results, take as directed on the product’s label.

Try: Nature’s Way Rhodiola Rosea Standardized Vegetarian Capsules

Karen MorseKaren Morse, MPH, is a freelance health and nutrition writer. In her free time, she enjoys Pilates, exploring nearby hiking trails and cooking up fresh, seasonal eats in the kitchen. Her work has appeared in Clean Eating, Weight Watchers, YouBeauty.com and others.