Written By: Kristen Boye

Are you an endurance athlete looking for ways to optimize performance, nourish your body and support your mind?

If so, you’re probably taking various dietary supplements.

You may even have a cupboard full of them, many of which did not live up to their claims or your expectations.

With so many products aggressively marketed to athletes, it can be difficult to determine which supplements will provide real, broad-spectrum, and lasting benefits.

In this article, we’ll help you cut through the athletic-supplement-hype with science-based information on five of the best supplements for endurance athletes. 

Five Best Supplements for Endurance Athletes

The best supplements for endurance athletes contain high-quality, easy-to-absorb essential nutrients that may be lacking due to the demands of training and high metabolism.

Although sports nutrition is not an exact science, research suggests endurance athletes require more calories, hydration, and specific nutrients to meet the demands of their sport, optimize recovery, and support various bodily processes.

The following are five supplements that have been shown to support the unique needs of endurance athletes*.

1. Iron

Iron is at the cornerstone of Floradix® products for a reason, it’s one of the most critical and often misunderstood nutrients.

Iron is an essential component of hemoglobin, a red blood cell protein that shuttles oxygen from the lungs to the tissues.

Iron also plays a vital role in:

  • Cellular function
  • Connective tissue function
  • Energy
  • Endurance
  • Growth
  • Muscle metabolism
  • Neurological development
  • Synthesis of specific hormones
  • And more

Unfortunately, iron deficiency or insufficiency is common and can be caused or exacerbated by:

  • A lack of dietary iron and/or other cofactors, such as vitamin C
  • Certain medications and medical procedures
  • Environmental factors, such as altitude
  • Exercise
  • Genetics
  • Inability to absorb iron
  • Menstrual blood loss
  • Pregnancy and giving birth
  • Surgeries or injuries

For these reasons, endurance athletes (especially menstruating women) need to be aware of their iron levels, which can be monitored through a simple blood test.

If your healthcare practitioner recommends an iron supplement, consider looking for a liquid supplement with synergistic herbs and nutrients that support optimal iron absorption and athletic performance.

2. Vitamin D

As a health-conscious athlete, you’ve probably heard all about the benefits of Vitamin D supplementation and optimizing your levels.

In fact, most doctors now screen annually for Vitamin D status, and supplementation is widespread.

Research has shown getting enough vitamin D, either through sun exposure and/or diet and supplementation, can support nearly every aspect of health, including:

  • Bone health
  • Calcium absorption
  • Cognitive health
  • Energy
  • Gut microbiome function
  • Heart and cardiovascular function
  • Hormonal function
  • Immune function
  • Mood
  • Metabolism
  • Sleep
  • And more

Research has also shown Vitamin D plays a role in muscle repair and function following intense exercise via its effects on muscle inflammatory response, muscle tissue, protein synthesis, and regulation of skeletal muscle function.

Unfortunately, Vitamin D deficiency is highly prevalent among athletes, possibly due to increased utilization and storage depletion, which is a good reason to consider supplementation and healthy sun exposure.

Talk to your doctor or healthcare practitioner for individual recommendations.

3. Magnesium

Magnesium, also known as the anti-stress mineral, is the second most abundant mineral and supports over 300 metabolic processes in the body.

Magnesium is related to many functions connected to athletic performance, including:

  • Blood pressure, resting and during and after exercise
  • Bone integrity
  • Calcium absorption
  • Energy production
  • Glucose levels
  • Glutathione production (your body’s master antioxidant)
  • Lactate clearance
  • Muscle function
  • Nerve function
  • Sleep
  • Stress response

Therefore, it has been studied as an ergogenic aid for athletes.

Magnesium status can be difficult to screen for as much of it is stored in the bones.

However, some studies have shown magnesium intake in endurance athletes is typically much lower than recommended for optimal performance.

Plus, many people do not consume enough magnesium-rich foods, such as leafy greens, almonds, and legumes, alcohol and taking certain medications can deplete magnesium, and your ability to absorb magnesium can decrease by as much as 30% as you age.

Eating magnesium-rich foods and supplementing with high-quality magnesium is a practical and inexpensive way to potentially support muscle function and repair, stress response, sleep cycle, nerve function, glutathione levels, energy production, and more.

Since there are many different forms of magnesium (citrate, glycinate, gluconate, etc.) and individual variables, more research is needed to know exactly how magnesium may benefit and support endurance athletes.

4. Zinc

Zinc has gotten much attention for its role in supporting various aspects of immune function.

Zinc also plays a vital role in:

  • Cellular function
  • Iron transport
  • Growth and development 
  • Gut health
  • Protein and DNA synthesis
  • Sense of taste
  • Skin, hair, and nail health
  • Wound healing

Research has shown that many people globally may not be getting enough zinc—especially those consuming no or minimal animal foods and lots of grains—or absorbing enough zinc from foods.

Common food sources of zinc include:

  • Oysters
  • Meats
  • Fish
  • Seafood
  • Eggs
  • Dairy products
  • Beans

Zinc absorption may be hindered by various factors, including phytic acids found in grains, nuts, and seeds which inhibit zinc absorption, as well as genetics and digestive health.

Emerging research also suggests that high-intensity physical exercise may change or deplete levels of zinc and copper (which have a synergistic relationship) due to its effects on metabolism, in which case supplementation may be helpful.

Talk to your healthcare practitioner if you suspect you are not getting enough or absorbing enough zinc.

5. B-Vitamins

B-vitamins include eight different nutrients, including

  • B1 (thiamine)
  • B2 (riboflavin)
  • B3 (niacin)
  • B5 (pantothenic acid)
  • B6 (pyridoxine)
  • B7 (biotin)
  • B9 (folic acid)
  • B12 (cobalamin)

These eight vitamins are essential for various bodily functions—from cognitive function and digestion to cardiovascular function, cell health, and energy.

Emerging research has shown endurance athletes may benefit from B-vitamin supplementation for supporting exercise endurance, energy, metabolism, red blood cell function, muscle building, and recovery.

Current research also shows that athletes may be more prone to suboptimal levels of specific B vitamins, especially if they are on very restricted diets, have eliminated food groups, have a genetic variation or mutation that hampers the absorption of crucial B vitamins such as folate or B12, or anyone eating no or minimal animal foods.

How To Get Started Optimizing Endurance Performance With Nutrition

Most endurance athletes are already familiar with various supplements for exercise recovery, performance, and inflammatory response.

If you’re interested in the five best supplements for endurance athletes listed here, talk to your sports nutritionist or healthcare practitioner.

They can recommend the best combination of nutrients based on your diet, training schedule and terrain (remember, high altitudes may affect nutrient levels), and individual needs.

Here’s to your optimal health and performance!