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Super 5: Herbs That Improve Endurance

These daily herbal supplements may enhance the effects of your training.

Let’s be clear: No herb is going to take you to the podium without your dedication to proper training and nutrition. However, if you’re already doing what you can in terms of diet and exercise, then adding a daily herbal supplement to enhance the effects of your training might serve as a “biochemical tune-up” for your body and help you reach the next level of performance.

Here are five dietary supplements that have been evaluated in research studies of endurance athletes on their ability to enhance oxygen efficiency, improve blood flow, balance hormone profile, and improve stress adaptation.


Rhodiola rosea on the rock near Slettnes Lighthouse, Norway
Photo: Getty Images

Rhodiola has been shown to have some pretty remarkable effects as a triple-threat analeptic for energy, focus and vitality, making it a favorite amongst endurance athletes. In fact, long before they were using synthetic steroids, the Russians tested Rhodiola their Olympic athletes, claiming it enhanced endurance and reduced recovery time.

Rhodiola helps improve oxygen transfer from lungs to red blood cells. It is a Himalayan root used by the Sherpa people to “adapt” to the stress of living and working at high altitudes. Even today, Sherpa climbers chew on rhodiola for an energy and endurance boost when helping mountaineers scale Mt. Everest. One mechanism for rhodiola’s anti-fatigue effects is an enhancement of oxygen efficiency — with subjects living at high altitude (5,380 meters) showing a beneficial effect of rhodiola supplementation on blood oxygen levels, time to exhaustion, VO2 peak, and pulmonary ventilation during endurance exercise. Additionally, its been shown to help the body produce adenosine triphospate (APT). This provides energy on a cellular level.

Dosage: 50-300mg (standardized to 5-6% rosavins)


Cordyceps fungus
Photo: Getty Images

Cordyceps helps speed transfer of oxygen from red blood cells to mitochondria. It is a Tibetan mushroom used in traditional Chinese medicine (TCM) for “lung protection” and to balance the “Qi” — the fundamental “energy of life.” In clinical studies, cordyceps feeding results in significant improvements in fatigue, oxygen uptake, and endurance exercise performance. Additionally, a 2016 study found that acute and consistent supplementation of cordyceps may improve tolerance to high intensity exercise.

Dosage: 100-500mg (standardized to 5-10% adenosine)


Eurycoma longifolia with green leave on white background.
Photo: Getty Images

Eurycoma balances two important hormones in the body — cortisol and testosterone. It is a root, often called Malaysian ginseng, that is used as a traditional remedy in Southeast Asia (Malaysia, Thailand, Vietnam) to help individuals “adapt” to the reduced energy and depressed mood that often come with chronic stress and overtraining.

Eurycoma contains a group of small peptides that are effective in restoring the balance between the cortisol and testosterone.

Dosage: 25-50mg (standardized to 20-25% eurypepides)

Eleuthero and Ashwagandha

Ashwagandha or winter cherry roots
Photo: Getty Images

Ashwagandha (Indian ginseng) and eleuthero (Siberian ginseng) provide resistance to physical stress and increase energy levels. They are used in traditional medicine as “adaptogens” to help the body adapt to stressful situations.

One study on ashwagandha published in International Quarterly Journal of Research in Ayurveda found that people who took a supplement of 300 mg of the herb two times a day for 12 weeks saw improvements in their VO2 max. Another study in Journal of Ayurveda and Integrative Medicine looked at elite cyclists who took 500 mg of the supplement twice a day for eight weeks and found that their endurance and VO2 max significantly improved.

Benefiting the nervous, endocrine, and immune systems, ashwagandha root nourishes and strengthens adrenal, thyroid and immune functions. It also helps to decrease inflammation and lower blood sugar. Because it stabilizes the adrenal system and lowers cortisol levels, ashwagandha root has become popular in recent years for relieving anxiety and, despite the herb’s energizing effects, as a sleep aid. If you run high mileage or are doing otherwise intense training, you put yourself at risk for elevated cortisol levels, sometimes chronically. This can have unpleasant consequences like fatigue, insomnia, weight gain, menstrual cycle disruptions, mental fog, vulnerability to infection, and increased risk of injury. Ashwagandha helps you chill out and adapt to whatever stressors you are putting on your body from harder training to anxiety.

Eleuthero was one of the first adaptogens to be recognized and adopted as an endurance enhancer and is generally considered more stimulating than ashwagandha. There has been extensive research on its ability to help minimize fatigue during endurance activities, as well as enhancing focus during times of fatigue. In one 8-week study on recreational male endurance athletes, eleuthero supplementation was found to enhance endurance capacity, elevate cardiovascular functions and alter the metabolism for sparing glycogen.

Dosage: Ashwagandha, 10-30mg (standardized to 5-10% withanolides); Eleuthero, 100-200mg (standardized to 0.5-1% eleutherosides)


About The Author:

Shawn Talbott holds a MS in exercise science (UMass) and a PhD in nutritional biochemistry (Rutgers) and competes in iron-distance triathlons and ultramarathons.