5 Best Endurance Supplements for Mental Fatigue

5 Best Endurance Supplements for Mental Fatigue

Before we get into the 5 best endurance supplements for mental fatigue, I think it’s important to discuss a couple important points regarding mental fatigue in endurance sports.

Mental fatigue is also referred to as central fatigue or cognitive fatigue. Mental fatigue is a cause for concern in all endurance sports and can wreak havoc on performance. When it comes to endurance sports, especially super-long duration events like ultramarathons, the mental game is every bit as important as physical ability.

Symptoms of Mental Fatigue in Endurance Sports

One of the primary mental/central fatigue symptoms during a long endurance event is cognitive impairment.

Cognitive impairment eventually leads to poor decision-making and impaired judgment. This could have multiple negative implications during an endurance event, including poor pacing strategy, impaired navigational skills (risk of getting lost or off course), and poor nutritional choices – such as an athlete not eating or drinking when they should.  

In extreme cases, significant cognitive impairment can be dangerous to an endurance athlete. In severe cases of sleep deprivation (which leads to cognitive impairment), it’s not uncommon for ultra-runners to hallucinate, lose touch with reality, and become disoriented. Combine that with technical terrain, water crossings, high altitude exposure, and steep cliff drops (as is the case in many ultramarathons), and one can understand that the situation can become dangerous*.  

*FYI, I’m in no way saying that in a situation like this, a supplement is the answer; it’s not – sleep is. I’m just pointing out the “severe end” of cognitive impairment in endurance sports. 

Another symptom of mental fatigue is sleepiness. Obviously, endurance athletes are not going to perform well when they are fighting to stay awake.  

Prevention is the Best Medicine 

An endurance athlete should be proactive and take preventative measures to decrease the likelihood and magnitude of mental fatigue. Many factors contribute to mental fatigue come race day, including sleep, nutrition, adequate recovery, and proper cortisol regulation.  

Believe it or not, there are also supplements that studies have shown to positively impact the mental component of endurance sports. This blog will discuss the 5 best endurance supplements for mental fatigue.  These supplements can provide relief and improved performance during time of cognitive fatigue, sleep deprivation, and psychological distress.

5 Best Endurance Supplements for Mental Fatigue

1.  BCAAs  

For in-depth information on how beneficial BCAAs can be for endurance athletes, check out any of these three blogs – BCAAs For Ultra-Endurance AthletesThe BEST Supplements for Endurance Recovery10 Best Supplements for Ultramarathon Performance.  

Although the benefits of BCAAs for endurance performance reach further than mental fatigue and cognitive impairment, this is arguably their most significant asset to endurance athletes.

Simplified, when endurance athletes exercise for extended durations, they deplete BCAAs and, at the same time, tryptophan increases. This BCAA: tryptophan imbalance increases the synthesis of 5-HT, and increased 5-HT causes central fatigue. By taking in BCAAs before endurance exercise, you are effectively preventing, at the very least delaying, this imbalance.

In very long bouts of endurance exercise, like ultramarathons, additional BCAAs should be taken during the event as well.

How much?  

Studies show BCAAs to be effective at preventing central fatigue in doses of 7-20 grams. Read that again….7 grams is the minimum amount of BCAAs SCIENCE shows to effectively prevent central fatigue.

DO THIS – Look at your endurance supplement. Does it contain BCAAs? Is there at least 7 grams? If not, why?! 

If not, according to the scientific literature, it IS NOT preventing central fatigue. Additionally, this is a little off-topic, but it’s not preventing muscle breakdown very well either, as this takes about 200 mg/kg to effectively do that  (Fouré & Bendahan, 2017).

For more information on all the benefits of BCAAs and how much is needed, READ THIS BLOG!

2.  Caffeine5 Best Endurance Supplements for Mental Fatigue

Something tells me you could have guessed that caffeine would make the top 5 best endurance supplements for mental fatigue. Caffeine is one of the most potent and studied ergogenic aids on the planet. 

Taking caffeine during times of mental fatigue, sleepiness, and fading cognition can turn things around like the flip of a switch. Always make sure to assess your tolerance of caffeine before utilizing it as mental aid in training or racing.

How much?

Depending on tolerance, 5 mg/kg of caffeine is recommended. This amount has been shown to improve mood and endurance performance after the onset of Fatigue (Azevedo et al., 2016). This is the equivalent of about 340 mg of caffeine for a 150 lb. endurance athlete.

3.  Adaptogenic Herbs

Adaptogenic herbs are great options for reducing stress, enhancing cognition, and improving athletic performance. The combination of these benefits, in addition to excellent safety profiles, makes adaptogenic herbs a good choice for endurance athletes.  

The two most effective adaptogenic herbs for endurance performance are Rhodiola Rosea and ashwagandha. Below are a few of the positive benefits of each of these amazing herbs.  

Rhodiola Rosea: In addition to the various endurance benefits of Rhodiola Rosea, this adaptogenic herb also has been shown to improve cognition and reduce mental fatigue during exercise (Walker & Robergs, 2006).  

Ashwagandha: Like Rhodiola, ashwagandha has numerous benefits that could benefit endurance performance. When it comes to mental benefits for endurance athletes, ashwagandha effectively reduces stress and improves cognitive function.  

These two herbs’ potent psychological/mental benefits would likely prove helpful to almost any endurance athlete, especially in more extended events, like ultramarathons.  To find out more about how Rhodiola and ashwagandha can benefit endurance performance check out 5 Great Benefits of Rhodiola Rosea for Endurance and KSM-66 Ashwagandha for Endurance Athletes: 10 Powerful Benefits.  

How much?  

Rhodiola should be taken as an extract (conferring 3% rosavins and 1% salidroside) in doses ranging from 50-500 mg.  

Ashwagandha is typically taken in doses of 300-1200 mg/day and is best taken as an extract. The most proven and potent extract available is KSM-66®.

Remember that adaptogenic herbs like Rhodiola Rosea and ashwagandha should be taken consistently (daily) for at least 3-4 weeks to see the best results. If an endurance athlete decides to use them for their first time on race day, results will likely be minimal.  

4.  Creatine

When most people think of creatine, they probably don’t think of its cognitive or endurance benefits. 

Creatine can actually be tremendously helpful for endurance athletes. Studies suggest that creatine may possess cognitive benefits for the general population, not just for athletes.  This is likely especially true for individuals who don’t acquire adequate creatine from their diets, such as vegetarians and vegans.

A relatively unknown benefit of creatine is its positive effect on performance during a sleep-deprived state, which is why it makes my top 5 best endurance supplements for mental fatigue.

A study on elite athletes showed that creatine significantly reduces impairments in skill execution during times of sleep deprivation (Cook et al., 2011). Because of this benefit, creatine may be the most advantageous to ultra-runners, and other ultra-endurance athletes as their events can often last over 24 hours.

Note – Creatine will cause slight weight gain, and some endurance athletes choose not to supplement with creatine for this reason. I would definitely recommend supplementing for all plant-based athletes and those who will experience extreme sleep deprivation during an ultra-endurance event.

How much?  

50-100 mg/kg of creatine has produced excellent results with no side effects. 5 grams is a good starting point for most athletes.

5.  L-Theanine

L-theanine is a non-essential amino acid that has been catching some buzz lately in the supplement world. Studies have suggested that L-theanine supplementation can alleviate stress, improve cognition, and promote relaxation. Additionally, when combined with caffeine, L-theanine produces what is commonly described as a “clean focus” rather than the jittery energy rush one can experience from caffeine alone.  

L-theanine might not be for all types of endurance efforts, however. Although L-theanine does not cause drowsiness when taken under normal circumstances, it may work unfavorably  when an individual is already tired and sleep-deprived. Ultramarathons are anything but normal circumstances.

For this reason, during ultramarathons, ultra-runners should probably not take L-theanine once sleep deprivation becomes a factor.  

How much? 

200-400 mg is a typical dosage rarely associated with side effects. When taking with caffeine, an equal ratio of L-theanine to caffeine has been recommended.

Summary: 5 Best Endurance Supplements for Mental Fatigue

Hopefully, you’ve learned enough about what I consider the 5 best endurance supplements for mental fatigue that you can make a choice as to which supplement, if any, is suitable for you. Remember, a supplement pales in comparison to proper preparation and prevention. However, when mental fatigue is inevitable, these five supplements should provide some relief and improve endurance performance.

T-30 is a daily endurance supplement formulated with super-long endurance efforts in mind. T-30 does many things, but one of the things it does best is preventing and delaying mental fatigue. For this reason, (and others), we believe T-30 is the best ultra-running supplement on the planet. To learn more about T-30, check out T-30: The KING of Endurance Supplements.



Disclaimer – Use common sense, and always listen to your doctor over a blog post. They know more about your health situation than anybody behind a keyboard. As someone who has a Graduate degree in Clinical Nutrition, I realize the variance that certain medical conditions create when it comes to optimal nutrition and supplementation. If you have underlying medical conditions, always check with your doctor before starting a new supplementation routine.



Azevedo, R., Silva-Cavalcante, M. D., Gualano, B., Lima-Silva, A. E., & Bertuzzi, R. (2016). Effects of caffeine ingestion on endurance performance in mentally fatigued individuals. European Journal of Applied Physiology, 116(11–12), 2293–2303. https://doi.org/10.1007/s00421-016-3483-y

Cook, C. J., Crewther, B. T., Kilduff, L. P., Drawer, S., & Gaviglio, C. M. (2011). Skill execution and sleep deprivation: Effects of acute caffeine or creatine supplementation – a randomized placebo-controlled trial. Journal of the International Society of Sports Nutrition, 8, 2. https://doi.org/10.1186/1550-2783-8-2

Fouré, A., & Bendahan, D. (2017). Is Branched-Chain Amino Acids Supplementation an Efficient Nutritional Strategy to Alleviate Skeletal Muscle Damage? A Systematic Review. Nutrients9(10). https://doi.org/10.3390/nu9101047

Walker, T. B., & Robergs, R. A. (2006). Does Rhodiola rosea possess ergogenic properties? International Journal of Sport Nutrition and Exercise Metabolism, 16(3), 305–315. https://doi.org/10.1123/ijsnem.16.3.305

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