Royal Jelly is a metabolism stimulant, it enhances the body’s ability to convert calories to energy. This simple yet important property improves muscle endurance. You could say it stimulates energy production.
Takahashi, Yumiko, et al. “Effects of Royal Jelly Administration on Endurance Training-Induced Mitochondrial Adaptations in Skeletal Muscle.” MDPI, Nutrients, 12 Nov. 2018, https://www.ncbi.nlm.nih.gov/
BeltrameDalepraneab, Julio, et al. “Anti-Atherogenic and Anti-Angiogenic Activities of Polyphenols from Propolis.” Elsevier, The Journal of Nutritional Biochemistry, 20 July 2011, https://www.sciencedirect.com/