| dc.description.abstract | The use of ergogenic compounds has gained increasing popularity among athletes who wish to
improve athletic performance and recover faster from their workouts. Among these products is
Citrulline Malate (CitMal); a precursor to nitric oxide (NO) that promises to enhance blood
flow to exercising muscles. To evaluate the purported effect on blood flow we assessed blood
flow in the arm of 12 healthy, recreationally active men (23 ± 3 years) pre and post intake of
placebo, 6 and 12 grams CitMal, with measurements done 1 and 2 hours post intake. The
experiment was conducted as a randomized, double-blind and placebo-controlled crossover
study with ≥ 7-day washout-period between each of the three sessions. Blood flow was
measured directly with ultrasound doppler in the reactive hyperemic state (FLOW) and
indirectly by assessing the dilator capacity of the brachial artery (a. brachialis) in the active
hyperemic state (FMD). Repeated measures ANOVA revealed no statistically significant
change in FLOW or FMD 1 and 2 hours post intake of placebo, 6 and 12 grams CitMal
compared to baseline values. The measurement data were also not statistically significantly
different between the groups at any of the measurement times, neither for FLOW nor FMD.
Out of the 12 participants, 8 of them underwent blood assessments after all blood flow
measurements were completed to assess the dose-response relationship between CitMal (6 and
12 grams, time window: 0-120 min) and blood markers involved in the production of NO.
Independent t-test revealed statistically significant higher serum levels of arginine and higher
ratio-values between arginine and its methylated derivatives symmetric dimethylarginine
(SDMA) and asymmetric dimethylarginine (ADMA) at all measurement times after
consumption of 6 and 12 grams of CitMal compared to baseline values. Taken together, these
data provide evidence that CitMal does not increase blood flow to musculature in the active-
nor reactive hyperemic state in young healthy males with normal blood levels of arginine.
Keywords: Citrulline Malate, nitric oxide, blood flow, arginine, symmetric- and asymmetric
dimethylarginine. | |