Thirty-three resistance-trained men took 8 g of L-citrulline, 12 g of citrulline malate, or a placebo each day while following the same 6 week training program. Both citrulline groups completed more total upper-body repetitions to failure than the placebo group and showed a higher post-exercise nitric oxide response. Maximal strength, rating of perceived exertion and lower-body repetitions to failure did not differ between the groups.
L citrulline is an amino acid the body converts to arginine, which is used to make nitric oxide. Nitric oxide widens blood vessels, so more of it should mean more oxygen reaching working muscle. Citrulline is sold as pure L citrulline and as citrulline malate, a salt of citrulline and malic acid. Little research existed on taking either form for weeks alongside training.
Thirty six resistance trained men were recruited and 33 completed the study: 11 on L citrulline, 12 on citrulline malate and 10 on placebo. The design was randomized, double blind and placebo controlled. The L citrulline group took 8 g per day, the citrulline malate group 12 g per day at a 2 to 1 ratio of citrulline to malate. Both groups and placebo followed the same program, four sessions a week for six weeks.
Measures before and after were maximal strength on hack squat and bench press, repetitions to failure on four lifts, perceived exertion, and blood lactate, urea and nitric oxide metabolites.
Strength was a null result. All three groups got significantly stronger over six weeks (p less than 0.001 for both lifts), but there was no group effect and no group by time interaction for the hack squat (p equals 0.763) or the bench press (p equals 0.517).
Upper body endurance was where a difference appeared. For total upper body repetitions to failure, the change from baseline was greater than placebo for L citrulline (difference 5.590 repetitions, 95% CI 2.94 to 8.24, p less than 0.001) and for citrulline malate (difference 4.458, 95% CI 0.52 to 8.40, p equals 0.026).
Lower body endurance did not separate cleanly. The overall test was significant (p equals 0.035), but the only pairwise result was a trend for L citrulline against placebo (p equals 0.070).
Nitric oxide metabolites rose over time in the L citrulline group (p equals 0.014) and the citrulline malate group (p equals 0.003) but not in placebo (p equals 0.450). At the end of the study, post exercise nitric oxide was higher than placebo for citrulline malate (p equals 0.009) and marginally so for L citrulline (p equals 0.057).
The sample is small: 33 men across three groups, so 10 to 12 people per arm. Diets were not standardized and were assessed only by three day food records. Only recreationally resistance trained men took part, so the findings do not extend to women or advanced lifters, as the authors state.
The supplements were not independently tested. The team relied on the manufacturer's certificate of analysis, and notes the citrulline malate group may have received about 0.4 g more citrulline. The placebo doses weighed less than the active doses, which may have weakened blinding. When asked afterwards, roughly a third of each group guessed their allocation correctly.
One author owns the gym where training took place. Another provides consulting services to dietary supplement manufacturers through his own company, though not to the makers of the products used here. The authors report no funding for the work.
The result is mixed. Six weeks of either form of citrulline produced more repetitions to failure on upper body lifts than placebo, and raised a blood marker of nitric oxide. Everything else was null: strength, lower body endurance, perceived exertion, lactate and urea.
The two forms performed the same, so there is no reason here to prefer one over the other. The study does not show improved strength, muscle size or protein synthesis, and it does not apply to women, who were not included. The endurance finding needs replication in a larger trial.
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.
