The effect of royal jelly supplement on athlete performance and gene expressions in endurance-trained men: A double-blind, cross-over, clinical trial

Determining the effect of the royal jelly dietary supplement on the maximum rate of oxygen consumption, oxidative stress indices following endurance activity, and the expression of PGC-1α and Nrf2 genes in trained men

A randomized, double-blind, cross-over, placebo-controlled, phase 2 clinical trial

The study participants will be recruited from the Faculty of Sport Sciences, Razi University, Kermanshah. Eligible participants will be randomly assigned in a ratio of 1:1 to either intervention or control group. Participants in the intervention group will take 1000 mg/day of royal jelly and the control group will take a placebo for 2 weeks. According to the cross-over design of the study, we consider 2 weeks as a wash-out period to eliminate the intervention and placebo effect. After that, the assignments will be changed between the two groups and the study will continue for two more weeks.

Men 18 to 44 years of age are eligible for inclusion in the trial if they provide written informed consent and have regular endurance activities at least 3 times per week in the last 6 months. We also exclude persons who have a history of any acute or chronic respiratory diseases, heart diseases, diabetes mellitus, metabolic disorders, musculoskeletal diseases, and injuries during training or exercise, use dietary and antioxidant supplements (such as vitamin E, vitamin C, β-carotene, selenium, and royal jelly) and anti-inflammatory drugs in the last 3 months, follow specific dietary programs; and have an allergy to bee products and royal jelly.

Participants in the intervention group will take 500 mg of royal jelly tablets, and the control group will take placebo tablets (containing 500 mg of microcrystalline cellulose) twice daily after breakfast and dinner for 2 weeks.

Endurance performance

The randomization in this study is based on the simple randomization method without stratification. The randomization sequence will be generated with the use of a computer-generated random-number table by the study statistician. Each random sequence will be recorded on a card, and then all cards will be sealed in sequentially numbered opaque envelopes. Envelopes will be opened in their numbered sequence after the enrollment of eligible participants. These participants will be randomly assigned in a 1:1 ratio in a blinded manner to the intervention or control groups.

In this trial, random sequences will be placed in sequentially numbered opaque envelopes and remain concealed until enrollment. Eligible participants will be randomly assigned in a 1:1 ratio in a blinded manner to the intervention or control groups. Participants and investigators, except the study statistician, will be concealed from the study‐group assignment until the end of the trial and data analyses. The placebo tablet will be identical in terms of shape, color, size, odor, and weight to the royal jelly tablet. All tablets will be enclosed in similar containers.

The non-identifiable individual participant data collected in this study will be shared. Also, The protocol, results, and statistical analysis of the current study will be published in the relevant articles.

The non-identifiable individual participant data will become available after the publication of the relevant articles.

The non-identifiable individual participant data will become available to other researchers in academic institutions.

The non-identifiable individual participant data can only be used for research.

The non-identifiable individual participant data will be obtainable by sending an e-mail to Dr. Yahya Pasdar. ( e-mail address: yahya.pasdar@kums.ac.ir)

Other researchers in academic institutions can send their requests by e-mail to Dr. Yahya Pasdar. The data will be sent to them after consulting and approving the research team.