About 90% of pre-workout supplements are an expensive, overcomplicated way to deliver caffeine to your system before training. That is not a hot take — it is basically what the label says when you read past the marketing copy.

My pre-workout of choice is black coffee. Has been for years. John Welbourn — former NFL player, founder of Power Athlete — put it simply: find the strongest coffee in the smallest cup. Drink it.

But does caffeine actually improve performance? Yes. Here is what the research shows and where it gets complicated.

What caffeine actually does

The mechanism is not magic. Caffeine improves your tolerance to exhaustion — you can push slightly harder and slightly longer before the body wants to stop. Do that consistently across training sessions and you accumulate more total quality work over time. More quality work over time equals getting stronger. That is the whole chain.

Research has also found that this effect may be more pronounced for lower body exercises than upper body work — worth knowing if leg strength is a specific priority.

The dose problem

Here is the catch: the studies showing meaningful performance improvements used a meaningful caffeine dose — around 6 mg per kilogram of bodyweight.

For a 180-pound athlete, that is roughly 490 mg of caffeine. More than two 5-Hour Energy shots back to back. Not something you want to be doing regularly, and probably not what you are getting from a single cup of coffee.

A large black coffee gets you into the 150–200 mg range depending on the brew. Enough to have an effect for most people — just not necessarily the effect size the clinical studies are measuring.

The tolerance problem

If coffee does not really do much for you anymore — if it does not sharpen anything, just prevents a headache — your tolerance has climbed to the point where most of the performance benefit is gone.

The fix is uncomfortable but straightforward: two to three weeks completely off caffeine, let the tolerance reset, then reintroduce it. After a proper reset, a single strong coffee before training will produce a noticeable effect again.

Worth doing periodically regardless.

The sleep problem

Caffeine has a half-life of about five hours, with significant individual variation. If you have caffeine within eight to ten hours of bed, some of it is still in your system when your head hits the pillow.

If sleep quality is poor and you are drinking coffee into the afternoon, this is worth experimenting with seriously. Sleep quality does more for your training than any supplement — caffeine included. The evidence on sleep and performance makes this case clearly. Optimizing caffeine on top of a poor sleep foundation is putting a fine edge on a dull blade.

The bottom line

Caffeine works. It is one of the few supplements with a genuine, consistent evidence base for performance improvement. But it works best when your tolerance is low, the dose is meaningful, and sleep quality is not undermining everything else.

A strong black coffee before training is a completely reasonable pre-workout. You do not need the tub of fluorescent powder with eighteen ingredients and a warning label. Save the money.