The first rule of supplements is, don’t take supplements.  By definition, they only supplement an already sound diet, which sad to say, doesn’t describe most people.  If you do have a good diet and exercise program, and have been consistent with it for more than a few months, then you might consider taking some supplements to enhance your performance.  This article will be for those people, and will cover scientifically validated supplements that will enhance your performance as a crossfit athlete.

Before we go any further, I would like to point out, as usual, that I am not a doctor, not even the Phoenix University kind, so I will only be giving you my interpretation of scientific research and nothing more.  Also, I do not receive any money from supplement companies and am unbiased in that regard.

You mean to tell me supplement companies sponsor bogus research to sell dubious products?

Furthermore, this will not be an exhaustive list of all supplements and their uses.  I will only be covering two of the most effective and well researched.  Lastly, I will not cover performance enhancing drugs or other substances of dubious legality.  Everything in this article will be legal and safe for the vast majority of people.


The first substance under discussion is HMB or β-hydroxy-β-methylbutyrate; now you see why I will be referring to it as HMB.  This chemical has a wide variety of uses and has been extensively researched.  Generally speaking, it is thought to enhance muscle recovery after difficult workouts.  It has also been shown to increase lean muscle mass, decrease body fat, increase strength, as well as anaerobic and aerobic output.  I know that sounds like a bad infomercial and I wouldn’t believe it had I not read so much research confirming these claims.

HMB is thought to work in a variety of methods.  First, it is believed to regulate what is known as the mTOR pathway.  Basically, mTOR is a chemical in your body that regulates protein synthesis in cells.  What does that mean to us?  HMB increases protein synthesis which accelerates muscle growth and increases strength.  It’s also believed to reduce cellular signals that cause atrophy in muscles.  This is all well and good, but what does this actually mean for your average gym rat, or crossfitter?

First, HMB has been shown to increase endurance both in maximal oxygen usage (VO2 Max), and the time it takes to reach that value.  To put it in terms that a crossfitter would be familiar with, this will increase the amount of power you can sustain without wanting to vomit, and it keeps you below that vomit threshold for longer.

In a very interesting study done on the Polish national rowing team, two groups were given either HMB or a placebo then put through the same 12 week training program.  The group that took HMB showed much greater improvement over the control group.  They increased their VO2 max 3 ml/kg/min from 67 -70.  This is astounding considering that they are already elite endurance athletes with huge V02 maxes.  As we know, it is easy to show improvement when you are new at anything, it is another thing entirely to show improvement when you are at an elite level.

VO2 Max Comparison
VO2 Max Comparison

The rowers also showed a 6% increase in anaerobic power on a wingate test, which is a 30 sec cycle test at max effort.  This is important to note as well, because it shows HMB increased their power output in a different exercise form than they are used to, i.e rowing.  This is great news for crossfitters as it won’t just increase your running times or your filthy fifty, it will help in all these domains.  As I alluded to earlier, HMB also increases maximal strength gains.

According to a research review on HMB, it increases strength through an increase in muscle size.  Researchers have found that it tends to work best on compound movements and less well on isolation movements.  It also works better in a periodized program, with increasing demands put on the body.  This basically describes a crossfit program that gets progressively harder, using multi-joint movements.

HMB and Creatine

Now that we know that HMB increases our strength and endurance, should we head down to the store and grab some?  I would say, not yet.  There has also been a fair amount of research on creatine and HMB usage combined. Interestingly enough, it shows an additive effect, with the total improvement being greater when they are together rather than separate.

In this 6 week study,  creatine, HMB and creatine+HMB groups gained 2, 0.85, and 3.4lbs of lean body mass, respectively.  These effects were additive because there was no interaction between creatine and HMB statistically speaking.  Across all exercises, creatine, HMB and creatine+HMB supplementation caused accumulative strength increases of 37.5, 39.1, and 51.9 kg, respectively, above the placebo group. They noted that the effects were more pronounced for untrained populations than for well trained athletes, but the effect remained for all groups.  In fact, this study looked at over 600 published studies over the last 50 years and found the two most effective substances were creatine and HMB.  Noticing a trend?

Lean Body Mass gain after 6 weeks
Lean Body Mass gain after 6 weeks, untrained subjects



The vast majority of researchers agree that 3g/per day is ideal for HMB.  Creatine is generally ingested between 2-10g per day with 5g being most common.  HMB should be ingested about 90 minutes prior to exercise and creatine can be ingested any time day or night.

Will it kill you?

The answer is, probably not.  This paper gave the Australian national rugby team both creatine and HMB for 6 weeks and measured their blood and even their semen samples.  They also underwent psychological evaluation to determine if it had any mental side effects.  Long story short, there were no meaningful changes to any physiological markers.  So, it’s safe to say, for healthy adults these substances should cause no side effects.


As with all research, the scientific method can only show you what worked for a certain group of people averaged together.  If you look at data in these studies, you will see that there are always some folks that show no change or get worse and some that show huge improvements, with the vast majority of people falling somewhere in between the two extremes.

First, I ask that you not take either of these substances if you have not stuck to a program for 6 months.  If I ask you how much sleep you’ve gotten the last couple of nights, and it’s less than 6 hours, you are also not a good candidate for taking these substances.  An extra two hours of sleep a night will yield much more improvement than either creatine or HMB.  If you have your ducks in order, then by all means try both.

You need to treat this like an experiment for your body.  Try a bench mark WOD or barbell lift before you start, and don’t change anything else about your program or sleep once you start taking HMB/creatine.  Try it for about 6 weeks and then retest.  If you show improvement, then you know you are getting your money’s worth.  If you don’t see any improvement, you might try repeating the experiment to confirm and if your results are the same you are probably a non responder.  This is the best way to make any change to your training, otherwise you are just guessing whether or not they make any difference.

Final Thoughts

Lets recap what we discussed.  First, don’t bother with supplements if you aren’t consistent with your exercise and diet.  Once those are in place, consider taking HMB and creatine stacked together, as they both affect strength, power output, and endurance.  Lastly, plan to take these supplements as a personal experiment, so you know if you are a responder to these chemicals or not.  Realistically, these substances won’t turn you into the Incredible Hulk, but they will give you an incremental advantage, which combined with consistency will put you way ahead in just a few months time.