Caffeine and Bicarbonate Together: Meta-Analysis Finds No Edge Over Taking One
Taking caffeine and bicarbonate together before a race sounds like a good idea: each one improves performance on its own, so the combination should help even more. A meta-analysis published in Nutrients, just indexed in PubMed, has pooled the trials that tested that combination. Its conclusion is cautious: caffeine and bicarbonate together barely beat a placebo, and there is no evidence they work better than taking just one of them.
What the study analyzed
The paper, by Chen, Tu and Wang, is a systematic review and meta-analysis published in Nutrients in 2026 (PubMed abstract). The authors searched PubMed, Web of Science and SPORTDiscus for every study up to July 18, 2026 that compared the caffeine and bicarbonate combination with a placebo or with each supplement alone.
They found 13 crossover trials, in which the same participants try every option on different days. They looked at mean power, time-trial performance, perceived exertion, blood bicarbonate and lactate, and gut symptoms.
The results for caffeine and bicarbonate together
| Comparison | Result |
|---|---|
| Combination vs placebo, mean power | 8.4 watts more |
| Combination vs placebo, time trial | About 1.6% faster |
| Combination vs caffeine or bicarbonate alone | No significant difference in power |
| Perceived exertion | No consistent effect |
| Gut symptoms | No consistent effect, limited evidence |
Compared with a placebo, caffeine and bicarbonate together increased mean power by 8.4 watts and cut time-trial completion time by about 1.6%. For a runner who does a 10K in 45 minutes, 1.6% would be about 43 seconds.
Both results were fragile: when the studies were removed one at a time, statistical significance disappeared in some cases. The authors conclude that the combination may bring modest gains, but that the findings are not robust.
What the combination has not shown
Is taking both worth it instead of one? This meta-analysis finds no evidence for it: the caffeine and bicarbonate combination did not improve mean power compared with caffeine alone or bicarbonate alone.
Its effect on the stomach was not clear either. Bicarbonate is known for causing gut problems, and the included studies showed no consistent pattern in either direction when it was combined with caffeine. The authors describe tolerance as still uncertain.
What it means for recreational runners
My practical reading, based on what the study says and what we already know about each supplement:
- If you are only going to try one, caffeine is the simplest. It works at low doses, 2 to 3 mg per kilo, and is easy to take as coffee, capsules or gels. I explain it in the article on caffeine for runners.
- Bicarbonate makes most sense for short, hard efforts from 30 seconds to about 10 minutes, such as an 800 m or 1,500 m, and its main drawback is the stomach. If you want to try it, the article on sodium bicarbonate for runners covers doses and how to reduce symptoms.
- Combining the two has not shown an extra benefit, and it adds two possible sources of gut trouble on race day. For most recreational runners it is not worth it.
- Test any supplement in training, never for the first time in a race. It is the same logic as training your gut before a marathon.
Limitations of the study
Thirteen trials is a small number, and the outcomes were measured as power and laboratory time trials, not long-distance running races. It is not clear that the results transfer directly to a recreational runner in a marathon. Some outcomes, such as blood bicarbonate, also relied on few studies or were highly heterogeneous.
Even so, it pools every trial on caffeine and bicarbonate together published up to July 2026 in the three databases searched.
FAQ
Can you take caffeine and bicarbonate together?
You can, and against a placebo the combination slightly improved power and time-trial performance. But according to this meta-analysis it does no better than taking just one of the two.
Which is better for running, caffeine or bicarbonate?
For most runners, caffeine: it is easier to dose, it works in longer events and it causes fewer stomach problems. Bicarbonate fits short, intense races better.
Does the combination cause more stomach problems?
The studies show no consistent effect. Gut tolerance of the combination remains unclear, so test it in training first.
