Caffeine and bicarb: do they really help you run faster?

Coffee and Bicarb: The easiest (legal) way to get faster?

When it comes to supplements and performance, most claims fall apart under proper testing. But every so often, something actually works — and caffeine is one of those rare exceptions.

A meta-analysis published in Frontiers in Physiology pulled together dozens of studies testing four common legal supplements: beta-alanine, bicarbonate, caffeine, and nitrate. The question: which, if any, really makes you faster? If you prefer to watch rather than read, you can check it out here (link to video).

The short answer

Caffeine and bicarbonate came out on top.

Both showed what researchers call a “small but significant” effect on performance. Small might not sound exciting, but in running terms, even a 1% boost can be the difference between missing and smashing your PB.

Let’s unpack what that means.

What the science shows

The researchers combined data from:

• 7 studies on beta-alanine

• 25 studies on bicarbonate

• 9 studies on caffeine

• 5 studies on nitrate

They converted everything into effect sizes — basically a standardised measure of how much faster, on average, athletes performed when using each supplement compared to a placebo.

Here’s what they found:

(You can see that visually in the chart above: caffeine and bicarbonate sit in the “small effect” range, while beta-alanine and nitrate barely move the needle.)

So how do they actually work?

Caffeine acts on your central nervous system. It reduces your perception of effort, helps you recruit more muscle fibres, and makes everything feel just a little bit easier. Most runners notice this effect — which is why that pre-race coffee has become a ritual.

Bicarbonate, on the other hand, acts as a buffer. It helps neutralise the lactate that builds up in your muscles during intense efforts. That’s why it’s most effective in short, hard endurance events — think 5K pace or interval sessions, rather than long, steady runs.

Beta-alanine and nitrates have both been hyped as performance boosters, but the evidence doesn’t really hold up. Some studies show minor benefits, others show none, and overall the picture is too inconsistent to trust.

The fine print

A meta-analysis is only as strong as the studies it includes. And in this case, many of the individual experiments were small and used very different methods.

Even so, caffeine’s benefit has been confirmed so many times, across so many studies, that it’s one of the few supplements worth real confidence. Bicarbonate also looks promising but it comes with a big caveat: gastrointestinal distress.

Put simply, if you don’t practise with it, it can give you the runs. Literally.

The Kaizen takeaway

If you’re chasing a PB over 5K or 10K, a coffee before your race is worth a try. It’s cheap, safe, and there’s solid evidence that it helps. 

Bicarbonate? Maybe but only if you’ve tested it in training first. For most runners, the risk-to-reward ratio isn’t great. For some of the “easier on the stomach” products, it also comes at a significant cost. And as for beta-alanine and nitrates, they’re probably not worth the hassle (or cost).

So the summary looks like this:

☕ Caffeine: Works, and works reliably.

🧂 Bicarbonate: Might help — but train your gut first.

💊 Beta-alanine: Unclear.

🥬 Nitrate: Probably not doing much.

FAQs: Using Caffeine and Bicarbonate for Performance

1. How much caffeine should I take?

Around 3–6 mg per kg of bodyweight, ideally 30–60 minutes before racing. For a 70 kg runner, that’s about 210–420 mg— roughly two to four espressos, or a strong coffee and an energy gel.

2. Can I just drink coffee?

Yes. Studies show similar effects from coffee and caffeine pills, though the dose is harder to control with coffee.

3. Does caffeine work for everyone?

Most people respond well, but some are more sensitive and may feel jittery or get an upset stomach. Always test it in training first.

4. How should I use bicarbonate?

Start with small doses in training — about 0.2–0.3 g per kg (14–21 g for a 70 kg runner) taken 1–2 hours before hard sessions. If your stomach tolerates it, it can help you hold higher intensities longer.

5. Can I combine caffeine and bicarbonate?

Yes, many elite athletes do. Just make sure your gut can handle both, and don’t try it for the first time on race day.

Bottom line

Caffeine is one of the few supplements we can confidently say helps you run faster. Bicarbonate might too — if your stomach can handle it.

Everything else? Probably not worth your time. Better to spend that energy on good training, smart recovery, and maybe a strong espresso before the start line.