Benefits
Lower salivary cortisol in moderately stressed adults (Relora blend)
In a 4-week randomized, double-blind trial in 56 adults screened for moderate stress, 500 mg a day of Relora, a blend of magnolia and phellodendron bark extracts, lowered salivary cortisol exposure by 18 percent compared with placebo. The trial was funded by the blend's manufacturer, and phellodendron was not tested on its own.
Mood state scores in moderately stressed adults (Relora blend)
In the same trial the Relora group had better Profile of Mood States scores than placebo, including lower overall stress (11 percent), tension (13 percent), fatigue (31 percent) and anger (42 percent) and higher vigor (18 percent). These are self-rated scores from one 56-person, manufacturer-funded trial.
Temporary anxiety ratings in premenopausal women (Relora blend)
In a 6-week double-blind trial of Relora 250 mg three times a day in 40 overweight premenopausal women who eat more under stress (26 completed), state anxiety, a measure of temporary anxiety, improved more than with placebo. Trait anxiety, salivary cortisol, appetite and sleep quality did not differ from placebo.
Body weight in women who eat under stress (Relora blend)
In a 6-week pilot trial in 28 overweight premenopausal women who eat more under stress, the placebo group gained an average of 1.5 kg while the Relora group did not change; 75 percent of the placebo group gained at least 1 kg versus 37 percent on Relora. The study was small, its first author worked for the manufacturer, and more people dropped out of the placebo group.
Mechanism of action
Magnolia and phellodendron in the studied blend
The trials tested Relora, a proprietary blend of Magnolia officinalis and Phellodendron amurense bark extracts standardized to at least 1.5 percent honokiol (from magnolia) and 0.1 percent berberine (from phellodendron). Because only the blend was tested, its effects cannot be credited to phellodendron alone.
Cortisol as the measured stress marker
The stress trials measured salivary cortisol. Exposure was 18 percent lower than placebo after 4 weeks in one trial, did not differ from placebo in a second, and showed only a non-significant trend toward lower evening levels in a third. How the blend might act on the stress hormone system has not been shown in people.
Berberine and related bark alkaloids
Phellodendron bark contains berberine together with palmatine and jatrorrhizine. In kidney transplant patients, berberine at 0.2 g three times a day raised blood levels of the drug cyclosporine, an effect the authors attribute to inhibition of the liver enzyme CYP3A4. The berberine content per dose of the studied blend is not reported beyond its 0.1 percent minimum.
Clinical trials
Randomized, double-blind, placebo-controlled trial of Relora 250 mg twice a day (500 mg a day) or rice-flour placebo for 4 weeks, funded by the manufacturer. (Talbott et al. 2013, J Int Soc Sports Nutr)
56 adults (35 men, 21 women) who completed the study out of 60 randomized, all screened for moderate stress.
Salivary cortisol exposure was 18 percent lower than placebo (p < 0.05), and Profile of Mood States scores were better for overall stress, tension, depression, anger, fatigue and confusion, with higher vigor and global mood. This is one small, manufacturer-funded trial of a magnolia and phellodendron blend.
Randomized, double-blind, placebo-controlled pilot trial of Relora 250 mg three times a day or placebo for 6 weeks. (Kalman et al. 2008, Nutr J)
40 overweight premenopausal women aged 20 to 50 who eat more under stress and had above-average anxiety scores; 26 completed.
State (temporary) anxiety improved more than with placebo. Trait anxiety, salivary cortisol and amylase, appetite, body measurements, and sleep quality and latency did not differ from placebo. No significant adverse events were reported.
Randomized, double-blind, placebo-controlled pilot trial of 250 mg capsules or placebo three times a day for 6 weeks; first author from the manufacturer. (Garrison et al. 2006, Altern Ther Health Med)
Overweight premenopausal women aged 20 to 50 who eat more under stress and had above-average anxiety scores; 28 completed.
The placebo group gained an average of 1.5 kg while the Relora group did not change; 75 percent of the placebo group gained at least 1 kg versus 37 percent on Relora (p < 0.04). Lower evening cortisol on Relora was only a trend, and more people dropped out of the placebo group.