Benefits
Short-term anxiety scores with a magnolia plus phellodendron blend
In a maker-funded six-week trial of Relora, a magnolia plus phellodendron blend standardized to honokiol and berberine, 40 overweight premenopausal women enrolled and 26 finished. State (short-term) anxiety fell more than with placebo, while trait anxiety, sleep and body measures did not differ. Two herbs were tested together, so magnolia alone cannot take the credit.
Salivary cortisol and mood scores in stressed adults on a two-herb blend
In a maker-funded four-week trial in 56 moderately stressed adults, Relora 500 mg a day lowered salivary cortisol exposure by 18 percent versus placebo and improved mood-state scores, including stress, tension, fatigue and vigor. The six-week trial in women found no cortisol difference from placebo, so the two trials disagree on cortisol.
Body weight in women who eat more under stress (two-herb blend)
In the same six-week maker-funded Relora trial of women who eat more under stress, a separate report found an average 1.5 kg gain within the placebo group and none with Relora, and fewer Relora users gained 1 kg or more (37 versus 75 percent). The trial's main report found no difference in body measures or appetite versus placebo.
Mood and sleep scores in menopausal women with magnolia added to isoflavones
In a randomized study of 634 menopausal women, an isoflavone tablet with added magnolia bark extract improved insomnia, irritability, anxiety and depressed mood more than the same tablet without magnolia over 12 weeks, while hot flushes improved equally. A smaller study of the same brand, listed with 50 mg magnesium, used calcium plus vitamin D3 as the comparator. Neither abstract describes blinding.
Sleep quality and time to fall asleep in a two-herb blend trial
The six-week Relora trial in women measured sleep quality and how long it took to fall asleep, and neither differed from placebo. In mice, injected magnolol and honokiol shortened the time to fall asleep and increased non-REM sleep through the benzodiazepine site, which has not been shown in people taking magnolia by mouth.
Breath freshness and plaque measures with magnolia bark gum and mints
In a 30-day randomized double-blind study of 120 adults, gum with magnolia bark extract lowered plaque acid production, salivary mutans streptococci and gum bleeding scores more than xylitol or control gums, and in 123 adults a gum with the extract plus zinc cut breath sulfur compounds more than plain gum for an hour. These products act in the mouth.
Mechanism of action
GABA-A receptor modulation (lab and animal studies)
In brain neurons and in cells carrying recombinant GABA-A receptors, magnolol and honokiol increased receptor responses at every subunit combination tested, most strongly at delta-containing subtypes. In mice, the sleep effects of injected magnolol and of injected honokiol were blocked by flumazenil, which points to the benzodiazepine site. These are animal and cell findings.
Cortisol and the HPA axis
Lower salivary cortisol was reported in one four-week trial of the magnolia plus phellodendron blend, while a six-week trial in women found no difference from placebo; a separate weight report from that trial described only a nonsignificant trend toward lower evening cortisol. The blend is also standardized to berberine from phellodendron, so magnolia's own share is unknown.
Antibacterial action against mouth bacteria (lab data)
In test-tube work, magnolia bark extract, magnolol and honokiol stopped the growth of Porphyromonas gingivalis, Fusobacterium nucleatum and Streptococcus mutans, bacteria linked to breath odor and plaque, at 8 to 31 micrograms per milliliter. This is the rationale for adding the extract to breath-freshening gum and mints.
Clinical trials
Randomized double-blind placebo-controlled pilot of Relora 250 mg three times daily for 6 weeks; the blend is standardized to not less than 1.5 percent honokiol and 0.1 percent berberine, and the study was funded by the maker Next Pharmaceuticals (Kalman et al. 2008, Nutr J)
40 overweight premenopausal women aged 20 to 50 who eat more under stress and scored above average for anxiety; 26 completed (16 on Relora, 10 on placebo).
Relora lowered state (short-term) anxiety versus placebo. Trait anxiety, salivary cortisol and amylase, appetite, body measures, sleep quality and time to fall asleep did not differ from placebo. Three people left because of adverse events (two on Relora, one on placebo). A separate weight report from this trial (Garrison et al. 2006) found fewer Relora users gained 1 kg or more (37 versus 75 percent).
Randomized double-blind placebo-controlled trial of Relora 250 mg at breakfast and dinner (500 mg a day) for 4 weeks, funded by the maker Next Pharmaceuticals (Talbott et al. 2013, J Int Soc Sports Nutr)
56 adults (35 men, 21 women) screened for moderate stress.
Salivary cortisol exposure was 18 percent lower than placebo (p<0.05), and mood-state scores were better, including overall stress (11 percent lower), depression (20 percent lower), fatigue (31 percent lower) and vigor (18 percent higher). No adverse events were reported. The product is a magnolia plus phellodendron blend standardized to honokiol and berberine.
Randomized multicenter parallel-group study comparing an isoflavone, Lactobacillus sporogenes, calcium and vitamin D3 tablet with the same tablet plus magnolia bark extract (Estromineral serena, which a 2006 study lists with 50 mg magnesium), one tablet at night for 12 weeks; blinding is not described in the abstract (Agosta et al. 2011, Minerva Ginecol)
634 menopausal women (300 without and 334 with magnolia) with typical menopausal symptoms and mild mood or sleep complaints, treated in 91 gynecology centers.
Both tablets reduced symptoms from baseline. The magnolia version improved insomnia, irritability, anxiety, depressed mood, tiredness and loss of libido more, while hot flushes, night sweating, palpitations and vaginal dryness improved similarly. Adverse events occurred in 1.2 percent with magnolia and 1 percent without.
Randomized controlled multicenter study of one tablet a day for 24 weeks of soy isoflavones 60 mg, lactobacilli, calcium, vitamin D3, magnolia bark extract 60 mg and magnesium 50 mg, compared with calcium plus vitamin D3 as an active control, not a placebo; outcomes were the severity and frequency of 11 symptoms: flushing, night sweating, palpitations, insomnia, asthenia, anxiety, depressed mood, irritability, vaginal dryness, painful intercourse and libido loss (Mucci et al. 2006, Minerva Ginecol)
89 symptomatic menopausal women (44 on the combination, 45 on calcium plus D3) with sleep or mood complaints; mean age 53.8.
All 11 symptoms decreased more with the combination than with calcium plus D3 from week 4, and well-being was rated good or very good by 66.7 versus 20 percent. Because the tablet held several active ingredients and the comparator was not a placebo, magnolia's own share cannot be separated.
Randomized double-blind three-arm study comparing a sugar-free gum with magnolia bark extract, a xylitol gum and a control gum, chewed daily for 30 days (Campus et al. 2011, Caries Res)
120 healthy adults with salivary mutans streptococci of at least 10^5 CFU/ml and bleeding on probing above 25 percent.
The magnolia gum lowered plaque acid production, salivary mutans streptococci and gum bleeding on probing compared with the xylitol and control gums. The abstract does not state the extract dose.
Randomized double-blind study of a 2.23 g sugar-free gum with 0.012 percent zinc acetate and 0.15 percent magnolia bark extract versus a plain gum, measured over two hours (Porciani et al. 2012, J Clin Dent)
123 adults (67 men, 56 women, mean age 37) with oral volatile sulfur compounds of at least 75 ppb.
Sulfur compounds fell 50.9 percent after 10 minutes of chewing the test gum versus 31.2 percent with plain gum, and 27.6 versus 6.9 percent after one hour, both significant; the two-hour difference (13.6 versus 2.3 percent) was not reported as significant. The extract was combined with zinc, so its own share cannot be separated.