Benefits
Lower anxiety scores with flower powder capsules
In a three-arm trial in postmenopausal women, 500 mg capsules of bitter orange flower powder for 8 weeks lowered state and trait anxiety by about 2 points on 20 to 80 point scales versus starch, similar to lavender. In 100 anxious pregnant women, capsules taken from 36 weeks to 2 weeks after birth gave lower anxiety scores than placebo; that trial is a study finding, not advice to use it in pregnancy.
Sleep quality scores with capsules or distillate syrup
In postmenopausal women, 8 weeks of flower powder capsules improved Pittsburgh sleep quality scores versus starch, though baseline scores differed slightly between groups. In 60 mothers of infants in intensive care, a week of orange blossom distillate syrup improved sleep disorder scores versus sugar syrup in an open-label trial.
Calm after a single dose of orange blossom distillate
In a double-blind trial in 60 healthy people aged 15 to 60, a single oral dose of orange blossom distillate (1 mL per kg) 2 hours before minor surgery was followed by lower anxiety scores, while scores did not change with saline. The analysis relied on within-group tests, so the size of the difference between groups is unclear.
Mood scores with flower powder capsules
In the pregnancy trial, fewer women taking flower capsules had postpartum blues at 2 weeks after birth (28% vs 54%), with no difference right after delivery. In 156 menopausal women with mild to moderate depression scores, 8 weeks of capsules lowered Beck Depression Inventory scores by about 3 points versus starch. Both trials were small and run in Iran.
Anxiety in a short open-label trial in stressed mothers
In 60 mothers whose newborns were in intensive care, a week of orange blossom distillate syrup did not lower state or trait anxiety scores compared with a sugar syrup, even though sleep scores improved. Participants knew which syrup they received.
Memory performance in a rat model (animal data)
In rats given scopolamine to impair memory, a bitter orange flower extract at 300 or 600 mg per kg a day for 15 days restored performance in avoidance and water maze tests and lowered a blood marker of oxidative damage. This has not been tested in people.
Mechanism of action
Flavonoids, synephrine and aromatic oil in the flowers
Dried flowers hold about 12% flavonoids, mostly neohesperidin and naringin. Their alkaloid fraction is about half synephrine, the amine concentrated in peel extracts, though amounts per cup or capsule have not been reported. The distillate and neroli oil carry linalool and linalyl acetate.
GABA-A benzodiazepine site involvement (animal data)
In mice, injected neroli oil protected against induced seizures, and the effect was reduced by flumazenil, which blocks the benzodiazepine site of the GABA-A receptor. This suggests the oil acts partly through GABA signaling, but it was not given by mouth and has not been shown in people.
What the body absorbs from the flower
After oral dosing in rats, more than 200 flower-derived compounds and metabolites were found in blood, urine and feces, with neohesperidin and naringin the main ones absorbed. In people who drank the flower tea, breakdown products of synephrine, neohesperidin and hesperidin appeared in urine and feces.
Clinical trials
Triple-blind, randomized, controlled three-arm trial: 500 mg capsules of bitter orange flower powder, lavender flower powder, or starch for 8 weeks, analyzed by intention to treat. (Farshbaf-Khalili et al. 2018, Complement Ther Clin Pract)
Postmenopausal women in Iran, 52 per group.
After adjusting for baseline scores, bitter orange lowered state anxiety by 1.99 points (95% CI 0.34 to 3.64) and trait anxiety by 1.76 points (95% CI 0.06 to 3.45) versus starch on the 20 to 80 point STAI scales. Lavender gave similar results, and the two herbs did not differ. The differences are small, and the confidence intervals reach close to zero.
Triple-blind, randomized, controlled three-arm trial: 500 mg capsules of bitter orange flower powder, lavender flower powder, or starch for 8 weeks; sleep measured with the Pittsburgh Sleep Quality Index. (Kamalifard et al. 2018, Women Health)
Postmenopausal women in Iran, 52 per group.
After adjusting for baseline sleep scores and confounders, sleep scores improved more with bitter orange than with starch (p < .001), and also with lavender (p = .003). Baseline sleep scores already differed slightly between the three groups (p = .045).
Randomized, triple-blind, placebo-controlled trial: 500 mg capsules of dried bitter orange flower powder (a ready-made Barij Essence product) or starch twice daily for 6 weeks, from late pregnancy to 2 weeks after delivery; funded by Shahrekord University of Medical Sciences. (Ahmadinia et al. 2026, BMC Complement Med Ther)
100 pregnant women aged 18 to 35 with mild to moderate anxiety, at 36 weeks or later.
Beck Anxiety Inventory scores were 5.90 vs 10.50 during labor and 3.48 vs 9.56 at 2 weeks postpartum on capsules vs placebo, from similar starting scores (11.76 vs 11.38). Postpartum blues did not differ right after delivery but were less common at 2 weeks (28% vs 54%, p = 0.008). Neither group reported adverse effects. The trial was not designed to establish safety in pregnancy and is not a recommendation for use in pregnancy.
Randomized controlled trial without participant blinding: syrup made from bitter orange blossom distillate or a sugar-water syrup of matched sweetness, 100 mL three times daily for 7 days; funded by Babol University of Medical Sciences. (Dehghan et al. 2024, PLoS One)
60 mothers with sleep complaints whose infants were in a neonatal intensive care unit in Iran.
Sleep disorder scores fell from 50.26 to 44.70 with the distillate syrup and from 50.46 to 48.53 with sugar syrup, a significant difference (p = 0.01, effect size 0.09). State and trait anxiety did not differ between groups (p = 0.122 and 0.144), although the discussion section describes lower anxiety.
Randomized, double-blind, placebo-controlled trial: steam-distilled bitter orange blossom distillate 1 mL/kg or saline 1 mL/kg by mouth 2 hours before anesthesia, from a Shahrekord University group that prepared the distillate. (Akhlaghi et al. 2011, Rev Bras Anestesiol)
60 healthy patients aged 15 to 60 having minor lower limb surgery, 30 per group.
STAI-state and APAIS anxiety scores fell after the distillate and did not change after saline. The authors report the distillate group as less anxious (p < 0.05), but the analysis used paired within-group tests, so the between-group difference is not clearly reported. Blood pressure and heart rate did not change in the distillate group, and no adverse effects were observed.
Metabolic profiling study in rats after oral dosing of bitter orange flower, using liquid chromatography and mass spectrometry. (Zhou et al. 2023, Rapid Commun Mass Spectrom)
Laboratory rats; plasma, urine and feces analyzed.
228 flower-derived compounds were tentatively identified (80 unchanged and 148 metabolites): 35 in plasma, 124 in urine and 156 in feces. Neohesperidin and naringin were the main compounds absorbed into blood, mainly transformed by sugar removal, methylation, glucuronidation and sulfation.