1.800.336.1977 Orders / Questions / Free Consultations
Buy $100.00 more for FREE shipping!

Product Detail & Benefits


The Anti-Fatigue Caps Formula:

Potassium/Magnesium Aspartate - A well-known nutritionist says it best regarding aspartic acid, "Because aspartic acid increases stamina, it is good for fatigue and plays a vital role in metabolism. It is good for athletes and helps to protect the liver by aiding in the removal of excess ammonia." Studies (Agersborg and Shaw 1962, Hicks 1964, Gaby 1982) show this combination provides substantial benefit for the prevention of fatigue. Aspartic acid also combines with other amino acids to form molecules that absorb toxins and remove them from the bloodstream, aids the function of RNA and DNA, and helps to protect the liver. Additionally, the potassium/magnesium aspartate compound increases production of a key substrate, oxaloacetate, which is involved in energy production. Lastly, the compound provides the minerals potassium and magnesium to help provide protection against cramping.

L-Citrulline - L-Citrulline is an amino acid that is found plant foods such as watermelon, onions, and garlic. Citrulline helps in the removal of ammonia in the muscles and liver, and, like aspartic acid, is beneficial in alleviating fatigue. L-citrulline is a precursor for the endogenous production of l-arginine. Increased blood levels of arginine significantly boost nitric oxide (NO) content. NO acts as a potent vasodilator, relaxing the arteries, and allowing them to widen. Vasodilation is responsible for increased blood flow to tissues such as muscle fibers, which supports enhanced athletic performance and cardiovascular health.

OKG - Both ornithine and alpha-ketoglutarate (OKG) provide a readily available, non-ammonia-producing source of glutamine in the body. Glutamine is depleted at high rates during exercise but cannot be replaced with regular glutamine as it produces ammonia on its own. OKG increases the amount of glutamine in the muscle and also helps prevent muscle catabolism. Colgan writes, "Both ornithine and alpha-ketoglutarate act in the body as an ammonia scavenger."

Beet Juice Powder - We use it to give the capsule contents some color, helping to differentiate them from similar-looking capsules such as Endurolytes. There's more to that, however, as Beet Juice Powder is rich in nitrates, which also help boost NO levels.

Rice bran, which is used as a flow agent during manufacture, is a healthy nutrient-rich alternative to processing agents like stearic acid and silicon dioxide.


Although Anti-Fatigue Caps is designed primarily for ammonia reduction in long distance events, the nutrients in the formula are excellent for helping counteract everyday fatigue.

Thoroughly tested over several years in the most extreme athletic endurance events, Anti-Fatigue Caps helps remove fatigue-causing, performance-robbing ammonia. During extended endurance exercise the body accumulates excess ammonia from protein metabolism, which interferes with glycogen production, disrupting energy output. Anti-Fatigue Caps is a one-of-a-kind supplement combining two well-known ammonia-scavenging nutrients. Clean up the waste products of combustion, or you'll pay the price. To stay strong in multi-hour events, you need Anti-Fatigue Caps.

Nutrition Labels:

Anti-Fatigue Caps
Supplement Facts
Serving Size 4 Capsules
Amount Per Serving % Daily Value*
Potassium Magnesium Aspartate 1000mg
Magnesium (as magnesium aspartate) 100mg 12%
Potassium (as potassium aspartate) 140mg 2%
OKG (Ornithine alpha-ketoglutarate) 700mg
L-citrulline 700mg
* The Percent Daily Values are based on a 2,000 calorie diet. Your daily values may be higher or lower depending on your calorie needs.
† Daily Value not established.
Other Ingredients: Beet Juice Powder, Stabilized Rice Bran, Vegetable Capsules (plant cellulose and water)

Fueling & Usage Tips

Race PR Kit - AES vol 8.14

Race PR Kit - AES vol 8.14

The ultimate performance-enhancing trio for race days!

Epic Sessions - Supplement suggestions for workouts and races

Epic Sessions - Supplement suggestions for workouts and races

The supplements suggested for use prior to an epic workout or race can be thought of as a preemptive strike...

Get the VIP Treatment
Join the Hammer VIP Program Today!

Product Reviews

Rated 5 out of 5 by from These ABSOLUTELY work with one caveat: These ABSOLUTELY work with one caveat: My personal experience is that AF caps work surprisingly well, unless you use them all of the time. It seems that with constant use (like daily rides), I either develop a tolerance or they just lose their "shine". BUT, when used only on those "special" or "gotta-go-hard-days" they are impressive. Constant use = "dull" or ineffective Occasional Use on Race Day Efforts = may impress you more YMMV
Date published: 2015-07-11
Rated 5 out of 5 by from Don't be Left in the Dark! I have been an endurance athlete for 6+ years and have just recently tried Anti-Fatigue Caps + Race Caps Supreme. I can't believe it has taken me this long to give one of the most effective performance enhancing products a try!! I was blown away by the difference this supplement combination made to my workout and overall energy within a high volume block of running workouts. If there is one combination to pen into your expense budget, it is Anti-Fatigue Caps + Race Caps Supreme!
Date published: 2014-03-13
Rated 5 out of 5 by from Pleasantly surprised about how good these are ! So I read the reviews and thought I'd give them a try - after all, Hammer products have never let me down so far.... and again, they didn't let me down. Having not run heavily in the last few years, I started running again, and to my pleasant surprise, when taking a couple of anti-fatigue caps in conjunction with a couple of endurolytes (which I also recommend) all washed down with lemon/lime HEED I found that I could run longer, faster and recover quicker - without the DOMS issues that I used to suffer from. Have just ordered some more. I am a convert !
Date published: 2015-02-23
Rated 5 out of 5 by from PR I used Energy Surge and Anti Fatigue Caps for the first time in a race. Couldn't believe the amount of energy I had at the starting line. I ended up running my fastest mile ever as well as setting a new Personal Record by 16 seconds in the 5K.
Date published: 2014-10-29
Rated 5 out of 5 by from Staple Product! Anti Fatigue Caps are an absolute essential Hammer product. Combined with Race Caps, I rely heavily upon these two products for maximum performance!
Date published: 2014-01-04
Rated 5 out of 5 by from These work I use these before a long run or hard work out. I have felt a difference in my energy, and I seem to be able to work out harder when I take them. In fact, I have started giving them to my husband before his work outs and high school aged kids before they ski and run and they all notice a difference too. Great product to help you get through a tough workout with energy.
Date published: 2015-11-22
Rated 5 out of 5 by from awesome I used it for a 6 mile run on the treadmill. I felt great. wanted to run forever. love this stuff.
Date published: 2015-01-27
Rated 5 out of 5 by from One Happy Marathoner I had always had issues with leg cramping in either the half marathon or the marathon. So, after reading about your products ability to eliminate lactic acid/ammonia build-up in the muscle tissue I decided to try it along with your endurolyte capsules, augmented with Hammer gels. It worked like magic. I had no cramping at all during the last LA Marathon. In fact I was able to speed up during the last mile of the race, which really tested the effects of your caps. I had a great race, and look forward to using your products in the future.
Date published: 2016-02-18
  • y_2017, m_1, d_19, h_1
  • bvseo_bulk, prod_bvrr, vn_bulk_0.0
  • cp_1, bvpage1
  • co_hasreviews, tv_0, tr_36
  • loc_en_US, sid_af, prod, sort_[SortEntry(order=RELEVANCE, direction=DESCENDING)]
  • clientName_hammernutrition