The authors pooled eight double-blind trials in which people took citrulline malate or a placebo before lifting weights to failure at about 70% of their one-rep max. On average the supplement group completed about three more repetitions than the placebo group, roughly a 6% increase. The effect was small, and when split by body region it reached statistical support for neither the upper body nor the lower body on its own.
Citrulline malate is a common pre-workout ingredient. L-citrulline raises blood arginine, which the body uses to make nitric oxide, a molecule that widens blood vessels. Individual trials on whether it lets people do more repetitions before their muscles give out had come back in both directions. This review pooled them to see whether an overall effect exists, and whether it differs between upper and lower body exercises.
A systematic review and meta-analysis. A meta-analysis pools results from separate studies into one estimate.
Effects were combined using Hedges's g standardized mean difference in a random effects model.
Pooled across all exercises, citrulline malate added 3 plus or minus 5 repetitions over placebo, a weighted difference of 6.4 plus or minus 7.9 percent (p = .022). The standardized mean difference was 0.196, 95 percent confidence interval 0.029 to 0.364, which the authors call small.
Neither subgroup reached the usual threshold. Lower body exercises gave 8.1 plus or minus 8.4 percent, effect size 0.266, confidence interval -0.001 to 0.533, p = .051. Upper body gave 5.7 plus or minus 8.4 percent, effect size 0.166, confidence interval -0.050 to 0.382, p = .131.
Publication bias tests were unfavorable. Egger's test gave a regression intercept of 1.45, p = .086, and a trim and fill analysis identified four missing studies and pulled the pooled effect size down from 0.196 to 0.104, confidence interval -0.017 to 0.216, no longer statistically significant. Removing one trial moved the main result to p = .052.
Eight studies and 137 people is a thin evidence base, and the subgroup analyses were thinner still, with 51 people across the lower body exercises. The trim and fill correction wiped out the headline result, and the authors say it should be read with caution. Five of the eight studies did not verify the content of the supplement they used, and two found less citrulline malate in the product than the label stated. No study measured citrulline, arginine or nitrite in blood or muscle, so the proposed mechanism was never confirmed. Three studies did not report side effects; in one that did, 6 of 41 participants, 15 percent, had stomach discomfort. The authors received no funding. Author A.M. Gonzalez declares he is Scientific Advisor to Shifted, a sports supplement manufacturer, though he states the manuscript was written before that role began.
The average result is small and fragile. It rests on young, mostly male, mostly strength-trained adults doing sets to failure, so it says nothing certain about untrained or older people, women as a group, or training that stops short of failure. It measures repetitions completed in a single session. It does not show gains in strength, muscle size or long-term adaptation, and the authors say those chronic effects have not been well studied. Read it as weak evidence of a small acute effect, not a settled finding.
That depends on the specific medication and formula. A few, like blood thinners with CurQLife or blood pressure medication with MaxiNOs, are worth a direct conversation with your doctor first. Check each formula's own FAQ section for specifics, or ask your health coach.
No, and we'd rather be upfront about it. Bacopa, the plant in BacoZest, has published human studies, though they used other bacopa extracts. OptiNOs and MaxiNOs each have human studies sponsored by their maker, Laila Nutraceuticals, which haven't been published in a journal. CurQLife's research is still early, from lab and animal studies, and we label it that way.
It depends on what you're building your routine around. BacoZest is built around bacopa, which is studied for memory.* OptiNOs supports strength and muscular endurance alongside resistance training.* MaxiNOs was studied for healthy blood vessel function.* CurQLife's research is still at the lab stage. Your health coach can help you pick a starting point.
All four are built around plant extracts. OptiNOs was reported as well tolerated in its human study, and published bacopa studies reported no serious side effects. CurQLife's safety data so far comes from lab and animal testing. Check with your doctor first if you're pregnant, nursing, on medication, or managing a health condition.
Because the patented ingredients behind our four formulas went through dedicated research, and research costs real money. A generic curcumin or bacopa supplement hasn't been tested in the form you get from us. You're paying for an ingredient with research behind it, not just a label.
Generic ingredients often haven't been studied in the specific form you're buying. Our four core formulas use patented ingredients, and we show you the research behind each one, including where it's still early.
It depends on the formula. In its study, MaxiNOs blood vessel response was higher than placebo 2 to 3 hours after the first dose.* OptiNOs and bacopa were studied over 6 and 12 weeks of daily use, so give them time. CurQLife is meant to be taken daily.
Yes. BacoZest, OptiNOs, MaxiNOs, and CurQLife are built for different goals, and none of them contain stimulants. They haven't been studied together, so ask your health coach how to fit them into your routine.
