Whenever I see someone touting the merits of, say, neuroscientist and podcaster Andrew Huberman’s $370 supplement stack, I’m tempted to go full PubMed on them. You really think the herbal extract Fadogia agrestis is going to boost your “healthspan and muscle performance” based on an obscure study of male albino rats published by the Asian Journal of Andrology back in 2005? A grand total of zero human trials is what Huberman means by a “robust foundation of science”?

But this kind of gladiatorial approach is likely to miss the mark. For one thing, there’s an ocean of weak and biased supplement research out there, so many popular supplements do have at least superficial backing from what looks at first glance like science. The real problem runs deeper, though. The quest for a silver-bullet performance boost presumes that these pills, potions, and hacks will improve your life in some meaningful, measurable way. And there’s reason to doubt this is true even when the supplements do what those who peddle them claim. Here’s why.

The first issue to consider is margins. There are a small handful of elite athletes around the world for whom a half-percent improvement in speed, strength, or recovery is meaningful. For the rest of us, even something that produces a statistically reliable improvement—a threshold that, according to the International Olympic Committee’s most recent scientific review, only caffeine, creatine, baking soda, nitrate, and possibly beta alanine meet—is unlikely to have any practical impact whatsoever on our lives. If the effect were large enough to matter, we’d be able to measure it easily instead of arguing about how to extrapolate from albino rat studies. Even the best-case scenario is comparable to a marathoner shaving her head: the aerodynamic advantage is real, but it’s also meaningless.

Then there’s the problem of individual variability. If an intervention produces a small positive effect on average, that almost certainly means some people get better and others get worse. This variability can be situational: you might experience positive effects one day and negative ones the next. Caffeine is the most exhaustively studied performance aid in the world. But because of differences in how people metabolize it, taking it does nothing for about half of endurance athletes, and makes roughly 8 percent of them slower. It’s tempting to think that you’ll be able to tell whether a supplement works for you, but when we’re talking about a margin of a percent or two layered over the day-to-day variability of normal life, with a twist of placebo effect mixed in, you’re probably kidding yourself.

Admittedly, these first two concerns are easy to brush away. I know from experience that when we train hard and push our limits, even marginal gains seem worth pursuing. Consider the cost of that pursuit, however. You have limited time, energy, and resources, and dedicating these to performance hacks can distract you from foundational stuff like training, recovering, eating, and sleeping well. But it’s not just the opportunity cost: paradoxically, taking what seems like a shortcut to better performance can nudge you toward doing a worse job on the basics.

A 2011 study in Taiwan illustrates this. Researchers gave a group of volunteers an inert supplement, telling half of them that it was a multivitamin and the other half that it was a placebo. Both segments thought they were helping with consumer product research, providing feedback on the size, shape, and texture of the pill. Then they completed a series of bogus consumer tests while the researchers monitored their behavior. While testing a pedometer, for example, those who thought they’d taken a multivitamin didn’t walk as far as the placebo group; at lunch, they were more likely to overdo it at the buffet table than to select the healthy organic option. In a questionnaire, the vitamin group reported less desire to exercise and greater desire for “hedonic activities” like drinking and—strikingly—casual sex.

As improbable as these results seem, they fit within a larger body of research on a psychological phenomenon called licensing. We often pursue goals that are in conflict with one another, like having an active social life while still getting plenty of sleep. When we make progress toward one goal, we feel justified balancing things out in the opposite direction. Have an afternoon nap and you might think it’s OK to stay out that night for one more drink. When it comes to supplements, the calculus is almost always lopsided. We dramatically overestimate the benefit, and subsequent licensing leaves us worse off than we started.

Of course, some supplements do work. Refueling with sports drinks during hard exercise lasting at least two hours has been shown to boost performance. But there’s a risk in ascribing too much power to external factors. Psychologists distinguish between an internal locus of control, believing that your fate is mostly determined by your own actions, and an external locus of control, attributing outcomes to chance or to outside forces. At the Cycling World Championships in 2013, American rider Taylor Phinney placed fifth, a disappointing result that his coach blamed on a dropped water bottle. In a race lasting hardly more than an hour, one less bottle shouldn’t have mattered—but on the razor’s edge, perception creates reality.

People with an internal locus of control tend to be more highly motivated, which makes sense since they believe working hard and trying their best will be rewarded. They’re also more likely to take up demanding sports like running and cycling, while those with an external locus of control are drawn to activities like golf and fishing. And athletes with an internal locus of control tend to have lower stress and anxiety, presumably because they believe they determine their fate. We all have a mix of internal and external factors influencing our performance, and an emphasis on supplements nudges us toward the latter—toward belief that success is a consequence not of blood, sweat, and tears, but of ingesting the right pills and powders (and hoping that our rivals haven’t discovered them yet).

These disadvantages might be worth tolerating if any of them really did deliver a significant edge. What would that look like? Think of the recent furor over carbon-plated running shoes: a demonstrated performance boost of as much as 3 percent has completely upended the sport. The reason supplements haven’t had a similar impact isn’t because they’re a secret that only Andrew Huberman’s listeners know about. It’s because they don’t work in any meaningful way.

Here’s a challenge, then. For one full training cycle, focus on the basics. Train hard, recover well, eat healthy, and get plenty of sleep. Tune out the noise. It’s impossible to predict how you’ll perform or feel, because life is full of uncertainties. But if you perform well, take this hard-earned psychological edge and etch it into your soul: the power is in you, not in any pill, powder, or online fitness trend.