A meta-analysis of royal jelly's reported effects on serum lipids in experimental animals and in humans found significant, positive results.

The substance significantly decreased serum and liver total lipids and cholesterol in rats and mice, and retarded the formation of atheromas in the aortas of rabbits fed hyperlipidemic diets.

Meta-analysis of controlled human studies also showed significant reduction in total serum lipids and cholesterol, and, in those with hyperlipidemia, it normalized HDL- and LDL-cholesterol determined from decreases in beta/alpha lipoproteins. 

The author of this meta-analysis concluded: "The best available evidence suggests that royal jelly, at approximately 50 to 100 milligrams per day, decreased total serum cholesterol levels by about 14% and total serum lipids by about 10% in the group of patients studied."

One group of researchers has reported that a royal jelly extract has potent antibiotic effects against gram-positive bacteria, but not against gram-negative bacteria. Royal jelly has exhibited immunomodulating effects in an animal model, stimulating antibody production and immunocompetent cell proliferation.

It has been claimed, anecdotally, for some time that royal jelly has anti-inflammatory effects and wound-healing properties. These claims were given preliminary support in a study of streptozotocin-diabetic rats. The researchers were looking for a hypoglycemic effect from royal jelly; none was found, but the researchers noted that royal jelly showed some anti-inflammatory activity and that it shortened healing time in desquamated skin lesions.

There have been scattered repots that royal jelly and its constituent 10-hydroxy-2-decenoic acid might have anti-cancer effects. There was one report that both provided complete protection against transplantable mouse leukemia. Tumor growth inhibition of other cancers has been associated with royal jelly supplementation in other animal models. More research is needed.