Key Takeaway
Six months of 3000 mg/day royal jelly in healthy adults improved red blood cell count, glucose tolerance, DHEA-S, and mental health scores versus placebo, with no serious adverse events.
Summary
Randomized, placebo-controlled, double-blind trial in 61 healthy Japanese volunteers aged 42-83. Participants were randomized to 3000 mg of royal jelly in 100 ml liquid daily or a matched placebo liquid for 6 months. The primary outcomes were anthropometric measurements and a broad panel of biochemical markers, including hematology, metabolic, hormonal, and mental health indices.
Fifty-six participants (30 royal jelly, 26 placebo) were analyzed. Compared with placebo, the royal jelly group showed significant increases in red blood cell count and reductions in erythrocyte sedimentation rate, improved glucose tolerance on OGTT, increased serum DHEA-S, and better mental-health sub-scale scores on a standardized questionnaire. No serious adverse events were reported, and there were no adverse changes in liver or kidney function.
This is one of the longest-duration human RCTs of royal jelly and provides supportive evidence that chronic supplementation at 3 g/day is well-tolerated and associated with multiple modest but consistent metabolic and hematologic improvements in middle-aged to older adults.