The researchers concluded that lemon verbena extract is a “safe and well-tolerated natural sports ingredient [which reduces] muscle damage after exhaustive exercise,” they wrote in the report, published recently in the Journal of the International Society of Sports Nutrition.
The extract used in the trial was Recoverben, a proprietary lemon verbena extract made by water extraction of organic dried Lemon Verbena (Aloysia citriodora) leaves. Vital Solutions GmbH, a German ingredient company which owns Recoverben, funded the current study and took part in discussions of the clinical trial design.
Study participants, supplementation, and exercise
Forty participants, 19 men and 21 women, were analyzed in the study. The criteria for inclusion were non-smoking, moderately active men and women between the ages 22 and 50 years with a BMI between 19 and 30 kg/m2. The researchers also narrowed down the study to include only participants who ate five or less portions of fruits plus vegetables on an average day.
The ingredients, 200 mg Recoverben or 200 mg of maltodextrin for the placebo, were formulated in capsules, matching in size and color, to comply with a randomized, placebo-controlled, double-blind and parallel study design. Each group, lemon verbena and placebo, had 20 participants.
Participants were instructed to take two capsules daily in the morning. In total, the intervention period lasted 15 days—products were consumed for 10 days before an exhaustive exercise test, during the test day and four days after the test.
The exercise protocol was an intensive jump protocol, which induces maximal eccentric loading of the lower extremity. The entire exercise routine included 200 counter-movement jumps with an additional load of 10% of the participant’s weight.
Polyphenols prevent muscle loss?
In the report, the researchers said that lemon verbena’s potential effects on exercise-induced muscle damage is similar to results seen in trials of other ingredients like ashwagandha extract, curcumin, pomegranate extract, and blueberry.
“These natural ingredients are high in polyphenols, a trait shared by lemon verbena,” they added. “It has been proposed, that polyphenols could be useful to prevent muscle damage or improve recovery.”
Results: Lower perceived muscle soreness for the lemon verbena group
Perceived muscle soreness—the primary outcome of the study—were measured using two different methods. For the first, researchers looked at movement-induced pain, where participants were asked to sit down into and get up from a chair and to rate the pain they experienced in doing so.
The other measurement was a seven-point pain questionnaire, where participants evaluated perceived pain during daily life activities, with zero being “a complete absence of pain" and six being "a severe pain that limits my ability to move". The questionnaire was answered immediately before the exhaustive exercise and 24, 48, 72, and 96 hours after the jump test.
Biochemical analyses were also analyzed to evaluate muscle damage and antioxidative capacity. Analyzed biomarkers included creatine kinase, glutathione peroxidase, and interleukin-6.
The researchers found that the participants who consumed lemon verbena benefited from less muscle damage as well as faster and full recovery. Compared to the placebo, the lemon verbena extract receiving participants had significantly less exercise-related loss of muscle strength over all time points, improved glutathione peroxidase activity by trend, and less induced pain by trend.
“Larger studies could provide statistical evidence also for the parameter, which only showed improvements by trend in the study,” the researchers wrote.
Source: Journal of the International Society of Sports Nutrition
Published online, https://doi.org/10.1186/s12970-018-0208-0
"Effects of lemon verbena extract (Recoverben) supplementation on muscle strength and recovery after exhaustive exercise: a randomized, placebo-controlled trial"
Authors: Sybille Buchwald-Werner, et al.