Beetroot juice and caffeine for muscle strength and endurance
What it found
In 13 resistance-trained men, beetroot juice and caffeine each improved muscle endurance in the back squat, and the combination worked slightly better.
Caffeine alone improved strength and power at high loads in the back squat, but beetroot juice alone did not.
What they found
Studies in people
Back squat strength and power
Caffeine improved mean velocity and power at 75%, 90% and 100% of one-repetition maximum in the back squat compared to placebo. Beetroot juice alone did not improve these measures.
Bench press strength and power
No differences were found in strength or power for the bench press with any supplement.
Back squat endurance
Caffeine, beetroot juice, and the combination all increased the number of repetitions, mean velocity and mean power at 65% of one-repetition maximum in the back squat compared to placebo. The combination gave slightly greater improvements in mean velocity and power than either alone.
Bench press endurance
No differences were found in endurance measures for the bench press with any supplement.
Isometric strength and jump
No differences were found in handgrip strength, mid-thigh pull, or countermovement jump height or power with any supplement.
Fatigue and side effects
Caffeine reduced fatigue perception compared to placebo. No differences were found in mood, nervousness, activeness, insomnia, gastrointestinal discomfort, headache or irritability.
What the authors conclude
“In conclusion, acute caffeine but not beetroot juice intake improves velocity and power production, particularly at high loads (75–100%1RM) and in lower-body (i.e., back squat) but not in upper-body exercises (i.e., bench press).”
Also in their conclusions
- They conclude that acute caffeine but not beetroot juice improves velocity and power production, particularly at high loads (75–100%1RM) and in lower-body but not upper-body exercises.
- They state that the single but particularly combined acute intake of beetroot juice and caffeine increases the number of repetitions, mean velocity and power production in muscular endurance at 65%1RM in back squat exercise.
- They suggest that in resistance-trained males, the combined beetroot juice and caffeine intake may produce a summative effect in fatiguing tasks where velocity and power production are required to be maintained.
How it was done
The authors wanted to see if beetroot juice and caffeine, which work in different ways, could have an additive effect on muscle strength, power and endurance. Previous studies had looked at endurance exercise like cycling, but not at short, intense efforts like lifting weights.
Thirteen resistance-trained men took part in a triple-blind, randomized, crossover trial with four conditions: caffeine, beetroot juice, both, or placebo. They drank 70 mL of beetroot juice (6.5 mmol nitrate) 180 minutes before exercise and caffeine (3 mg/kg) 60 minutes before, then did bench press and back squat tests for strength, power and endurance.
What it can’t tell you
- This was a small study in 13 resistance-trained men, so the results may not apply to women, untrained people, or other groups.
- The study could not measure blood levels of nitrate or caffeine, so it cannot confirm whether the supplements were absorbed as expected.
- The testing order was fixed, with endurance before strength, so fatigue may have affected later tests.
Who paid
- Conflicts
- Declarations. Competing interests: The authors declare no competing interests.
- Authors work at
- Faculty of Human and Social Sciences, Spain
The paper
- Title
- Single and combined effect of beetroot juice and caffeine intake on muscular strength, power and endurance performance in resistance-trained males
- Type
- Randomised controlled trial
- Evidence
- Studies in people
- Summarised from
- Full text
- Cite
- Montalvo-Alonso JJ, Del Val-Manzano M, Ferragut C, et al (2025). Single and combined effect of beetroot juice and caffeine intake on muscular strength, power and endurance performance in resistance-trained males. Scientific reports. doi:10.1038/s41598-025-02021-yFree full textPubMed 40369047DOI
Summary written 26 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error