What’s the Best Pre-Workout for CrossFit?

woman drinking from shaker bottle

Ever feel like you need a little extra oomph at the gym? We’ve all been there! A good pre-workout is no substitute for a rest day if it’s been a while, and it definitely can’t make up for crappy sleep. But if you just need a little motivation, a good pre-workout may do the trick. But what’s the best pre-workout for CrossFit?

Let me break it down for you. But first, let’s talk about what pre-workout is and whether you should take it.

What is Pre-Workout?

At the risk of sounding like Captain Obvious, pre-workout is a supplement you take before you work out.

There are lots of different formulations out there. However, most pre-workouts contain a mix of performance-enhancing substances like caffeine, sugar, amino acids, creatine, beta-alanine, and nitric oxide.

Like any supplement, there are lots of high-quality pre-workouts on the market, and perhaps even more shitty ones (more on that in a sec). But there’s some evidence that a good pre-workout can help increase both muscle stamina and motivation during workouts.

Should You Take a Pre-Workout?

As a registered dietitian, I’m generally a proponent of getting your nutrition from actual food.

I can say with 100% certainty that you can do just fine in CrossFit without using pre-workout. I typically drink a bit of cold brew and 1/2 of a banana shortly before a workout and feel fine.

That being said, I keep a pre-workout on hand for those days when I just can’t even…but I still want to get a workout in. I like the flavor and it gives me a little pep in my step, so I have no problem using it once in a while. If you want to give it a try, go for it! But there are a few things you should watch for.

What to Look for in a Pre-Workout

If you’re on the market for a pre-workout, the first thing you should look for is a product that’s third-party tested.

There’s not a ton of oversight in the supplements industry, and therefore, it can be difficult to know if any labeling and marketing claims are actually true.

When you buy supplements that have been tested by a third party, like NSF or informed choice, you can be confident that your products are free from contaminants and that the information on the label is accurate. This is especially important if you compete at a high level and are subject to drug testing.

This information is usually on the front of the package. NSF also has a searchable products database, if you don’t want to go on a supplements store scavenger hunt.

But third party testing aside, what should you look for?


If you can’t function without a cup of coffee in the morning, you can probably appreciate why a little caffeine might be helpful in a pre-workout.

The keywords here are “a little.”

Some pre-workouts contain so much caffeine you run the risk of pooping your pants. And while I admittedly don’t know everything about sports performance, I can tell you that you can’t PR a WOD if you spend half the time on the toilet.

Also, a pre-workout with too much caffeine could actually backfire if you do CrossFit because you want to get strong.

Here’s the deal. Sleep is when your muscles get big and strong. And drinking too much caffeine–in general, in your supplements, or too late in the day if you hit the PM classes–can keep you up at night.

Generally speaking, it’s best to cap your caffeine intake at 400 milligrams per day (and some pre-workouts have more than that!). One way to figure out how much you can handle is to calculate your daily caffeine intake and see how much wiggle room you have.

Keep in mind that caffeine has a half-life of up to seven hours (so higher doses in the afternoon are no bueno).

You can always start with a half scoop of powder to gauge your tolerance if you’re not sure.

Other Ingredients:

Caffeine aside, there are a few ingredients that tend to show up in pre-workout supplements. You might or might not want these ingredients in your pre-workout–it all comes down to goals, preferences, and tolerance.

Let me just tell you what they can do for you, so you can make informed decisions.


It’s really best to avoid sugar-sweetened drinks most of the time, but a bit of sugar in a pre-workout can actually be a good thing.

Carbs are your body’s most readily available source of fuel during workouts, but we can start to run low during high-intensity or long-duration workouts.

The sugar in pre-workout is top off your carb reserves a bit, so you have a bit of extra energy during your workouts.

Just a heads-up: There are lots of different code words for sugar. If you see an ingredient you don’t recognize that ends in -ose, that’s a good tip off that the product has sugar.


Electrolytes, like sodium and potassium, help regulate fluid balance and muscle contraction. They’re often added to pre-workouts to promote hydration and recovery.

Amino Acids

Amino Acids are the building blocks of protein, which we use to build muscle.

There’s some evidence that taking them can improve muscular endurance and increase protein synthesis. However, most people can probably get away with just eating protein shortly after training.

As is the case with sugar, you sometimes have to do a little label de-coding. Leucine and valine are both amino acids that you might find in pre-workout.


Creatine is a substance that helps your muscles make more energy during high-intensity exercise.

One of the most extensively researched supplements available to athletes, creatine increases exercise capacity and muscle strength.

The caveat is, you need to take creatine every day to see any benefit. You’d be better served to use a separate creatine supplement if you only take pre-workout occasionally.


Beta-alanine can help delay the buildup of lactic acid in the muscles during high-intensity workouts lasting 10 minutes or less (think Fran, assault bike sprints, or similar). Some studies suggest that taking it with creatine could be especially beneficial.

Like creatine, you need to take beta-alanine daily for it to make much of a difference. I’m guessing you don’t use pre-workout on your rest days, so you could probably skip it in your pre-workout and add a separate supplement if needed or desired.

Nitric Oxide

Nitric oxide is thought to increase blood flow (and therefore, oxygen) to the muscles. Overall, the evidence is pretty mixed as to whether it boosts exercise performance.

How to Use Pre-Workout

So just to circle back, you could use pre-workout occasionally or not at all! It’s all up to you!

There are some reports that taking it all the time could desensitize you to its effects, so you might want to plan for some breaks every now and again if you use it every day.

If you decide to use it, it’s best to take it about 30 minutes before the start of a workout.

I always recommend starting with 1/2 scoop anytime you try a new product, to lessen the chances of jiitters and other side effects.

You might also consider trying a lower dose in general if you workout in the afternoon or evening, especially if your product has caffeine.

The Best Pre-Workout for CrossFit

Now that you have a sense of what pre-workout is, whether you’d benefit from taking it, and how to use it, let’s talk about the best pre-workout for CrossFit.

Here are a couple I like:

Klean Athlete Pre-Workout

Klean Pre-Workout contains 75 mg caffeine per scoop, plus 2 grams sugar (cane sugar), 140 mg sodium, 5 g beet root extract (FYI, beets contain nitric oxide), and 150 mg vitamin C. It’s NSF certified for sport.

Ascent Pre-Workout

Ascent Pre-Workout is third-party tested and comes in two flavors–orange mango and raspberry lemonade. One scoop contains 150 mg of caffeine, plus 1 g sugar, 5 g protein, 250 mg sodium, and 32 mg potassium. Just FYI, the protein in this one comems from whey isolate, so it’s not suitable for vegans.

These are two of the best out there, in my opinion as a dietitian. I use them personally from time to time, and we sell them in the gym.

26, you can grab yours next time you’re in class!

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