Pre-workout supplements are ridiculously popular—and that’s because they really do help you get amped before training. They can even boost your athletic performance. Considering how many different formulas are out there, though—from high-stim options to caffeine-free pump products—figuring out which pre-workout is best for you can be a bit of a process.
To get the most out of your pre-workout (and your actual training), you’ve got to be willing to take a bit of a Goldilocks-style approach to sampling the different pills, powders, and ready-to-drink beverages out there. An important part of that: knowing when it’s time to switch things up.
Here, experts break down six telltale signs it’s time to try a new pre-workout formula.
1. Tingling skin is driving you crazy
Some athletes notice a tingly feeling under their skin that kicks in after taking a pre-workout that contains beta-alanine, according to dietitian Kim Yawitz, R.D., owner of Two Six Fitness in St. Louis, MO.
Beta-alanine, which is a common ingredient in all sorts of pre-workouts and sports nutrition supps, is a modified version of the amino acid alanine that helps delay the buildup of acid in your muscles during intense workouts. This supports your ability to keep grinding away. Scientists can’t say for sure why beta-alanine makes some people itchy, but one theory is that it activates protein receptors that make neurons in your central nervous system more “excitable,” Yawitz explains.
The skin tingles are most common in athletes who take large doses of beta-alanine, and a lot of pre-workouts don’t contain enough to cause the weird sensation, Yawitz says. If you’re noticing the pins-and-needles feeling and find it distracting, check to make sure you’re not consuming more than 800 milligrams of beta-alanine at once (since that amount has been linked to the creepy-crawlies). That said, even if you notice the sensation from a formula with less beta-alanine and don’t care for it, swap it out for a pre-workout that either contains less beta-alanine or leaves it out completely.
2. Bathroom Breaks Are Interrupting Your Workouts
If you feel your stomach start to bubble in the middle of a set after chugging pre-workout, you’re definitely not alone. This frustrating scenario might not be a popular topic amongst your gym buddies, but it’s a pretty common occurrence. Turns out, a lot of athletes report an increased urgency to poop after drinking pre-workout, Yawitz says.
“Some of the ingredients that make pre-workouts effective can, unfortunately, cause this side effect,” Yawitz says. “This is actually the number one reason my athletes switch formulas!”
Oftentimes, this sudden urge to go No. 2 comes down to caffeine, as some pre-workout formulas contain as much of the stimulant as four cups of coffee, she explains. To put that in perspective, some estimates suggest that coffee increases bowel activity by 60 percent more than water—so it’s easy to see why pre-workouts high in caffeine might make you need to poop at an inconvenient time.
If you’re constantly pressing pause on your workouts to make a beeline for the bathroom, consider switching to a pre-workout that contains less caffeine, or none at all.
3. You’re No Longer Feeling Caffeine’s Effects
According to The Vitamin Shoppe nutritionist Brittany Michels, M.S., R.D.N., L.D.N. C.P.T., our bodies can become tolerant to caffeine and its stimulating effects over time. And while studies show that caffeine promotes muscle power, strength, and performance, all while warding off the onset of fatigue, these benefits may decrease as caffeine tolerance increases.
It’s possible that as your caffeine tolerance builds up, you may notice your favorite pre-workout just doesn’t cut it anymore. (FYI: Those who consume pre-workout daily or almost daily are more prone to this effect.) If you’re a daily or almost daily pre-workout user and feel like your supp’s benefits are fading, consider switching to a non-stim pre-workout for some of your workouts. Or, if you’re up for the challenge, consider going all-in on a non-stim pre-workout for two to three weeks and then reintroducing your go-to stim product.
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Of course, if you’re still getting benefits from your usual caffeine-containing pre-workout, keep on keeping on, Michels says. But if you’re ready to incorporate something sans stimulation, her go-to ingredients are l-citrulline, l-arginine, or beetroot powder, all of which support the body’s production of nitric oxide and boost blood flow to your hard-working muscles.
4. You’re having trouble sleeping
“Maybe you train later in the evening and don’t want the caffeine or other stimulant’s effects keeping you up at night,” Gethin says. “Your recovery dictates your performance in the gym, so if you’re not sleeping well, you can’t expect yourself to perform well.”
That said, even if you don’t work out at night and notice that you have trouble sleeping on days you take a pre-workout that contains caffeine or other stimulants, switch to something stim-free and see if you notice improvements, he suggests. You might just be a slow caffeine metabolizer.
5. You’re Getting Headaches
A number of factors—from stress and forgetting to eat to eyestrain and dehydration—can explain why you get headaches. But your pre-workout could be a factor, too.
For some people, circulation-boosting ingredients like l-citrulline can actually have this effect. “Citrulline works by dilating blood vessels, increasing blood pressure and blood flow to tissues,” says explains dietitian Wendy Lord, R.D., a contributor to health professional network Health Reporter. “During such a process, the blood can get to the brain faster, which is why headaches can be experienced.” Similarly, too much caffeine can also cause headaches, she adds.
If you notice your head pounding during or after training sessions you pre-gamed with pre-workout, you may want to try a formula that doesn’t contain caffeine or citrulline and see how you fare with that.
Additional Consideration: Have Your Fitness Goals Changed?
Different pre-workout formulas contain different arrays of ingredients, all serving unique functions, in order to support different fitness goals, according to Michels.
Supplements created to support your goal of getting absolutely shredded, for example, often contain specific ingredients such as l-carnitine, conjugated linoleic acid (CLA), green tea extract, cayenne pepper extract, caffeine, and yohimbe, she says. So, if your goal is to shed fat, scan the label of your pre-workout to identify some of these ingredients.
Meanwhile, if you’re looking to bulk, research has shown that creatine can support muscle growth and strength, so opting for a pre-workout that offers creatine—and skips those pro-shredding players—may be a better bet.
For that reason, it’s helpful to take inventory of your supplement routine as the seasons—and your specific training and body composition goals—change, so that you can switch things up accordingly.