Limited evidenceStress & mood

Phellodendron Bark

Sold almost exclusively paired with magnolia bark in a proprietary extract marketed for cortisol and stress. Two small, industry-funded trials found modest effects; nothing larger has confirmed them.

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What the science says

Perceived stress and cortisol Limited evidence
A 6-week double-blind trial in 40 moderately stressed adults using a magnolia-phellodendron extract reported lower salivary cortisol and better mood scores than placebo. The sample was small and the study was funded by the ingredient manufacturer.
Stress in healthy women Limited evidence
A pilot double-blind placebo-controlled trial in 28 premenopausal women found a reduction in a transient anxiety scale but no significant change in cortisol or overall stress questionnaires. The authors described the result as preliminary.
Weight and stress-related eating Limited evidence
A pilot double-blind trial in overweight women reported that the extract prevented weight gain relative to placebo over 6 weeks, without an effect on cortisol. This finding has not been replicated in a larger trial.

Dosage & safety

Studied doseTrials used a proprietary magnolia + phellodendron extract at 500–750 mg/day, taken in two to three divided doses. There is no established dose for phellodendron bark alone.

SafetyShort-term trials reported mild side effects such as drowsiness, heartburn and headache. Phellodendron contains berberine, which can inhibit CYP enzymes and interact with many drugs and which should be avoided in pregnancy, breastfeeding and in newborns. Data beyond a few weeks of use are lacking.

How to take it

TimingTwo to three divided doses across the day, as in the trials; take the last one in the evening since drowsiness is a reported effect.

With food?With food, which reduces the heartburn reported in the short-term trials.

Worth knowingThe trials tested a fixed magnolia plus phellodendron combination, not phellodendron alone - a solo phellodendron capsule has no dose behind it.

Interactions

With medications

ciclosporin and other immunosuppressants
Berberine, the main alkaloid in phellodendron, raised ciclosporin blood levels substantially in transplant recipients by inhibiting CYP3A4 and P-glycoprotein. do not combine without transplant team supervision and drug-level monitoring
other CYP3A4 substrates with a narrow margin, such as warfarin, tacrolimus, some statins and certain antiarrhythmics
Berberine inhibits the same enzymes and can raise their blood levels. do not combine without your prescriber's agreement
metformin, sulfonylureas and insulin
Berberine lowers blood glucose, adding to these drugs and increasing hypoglycaemia risk. monitor glucose closely if you start it, and discuss dose adjustment with your prescriber

Well-established interactions only — this is not a complete list. Always tell your doctor and pharmacist what you take.

Frequently asked questions

Does phellodendron lower cortisol?

The evidence is limited. A 6-week trial in 40 stressed adults found lower salivary cortisol with a magnolia-phellodendron extract, but a separate pilot in 28 women found no cortisol change, and both were small and industry-funded.

How much phellodendron should I take?

Trials used a proprietary magnolia plus phellodendron extract at 500-750 mg/day in two to three divided doses; there is no established dose for phellodendron bark alone.

Does phellodendron interact with medications?

Yes. Phellodendron contains berberine, which inhibits CYP3A4 and P-glycoprotein and raised ciclosporin levels substantially in transplant recipients, and it also lowers blood glucose. Do not combine it with immunosuppressants, narrow-margin drugs or diabetes medication without your prescriber's agreement.

Scientific references

Effect of a proprietary Magnolia and Phellodendron extract on stress levels in healthy women: a pilot, double-blind, placebo-controlled clinical trial
Kalman DS, Feldman S, Feldman R — Nutr J, 2008
Effect of Magnolia officinalis and Phellodendron amurense (Relora®) on cortisol and psychological mood state in moderately stressed subjects
Talbott SM, Talbott JA, Pugh M — J Int Soc Sports Nutr, 2013
Effect of a proprietary Magnolia and Phellodendron extract on weight management: a pilot, double-blind, placebo-controlled clinical trial
Garrison R, Chambliss WG — Altern Ther Health Med, 2006

Related in Stress & mood

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Herbal medicines: what the evidence says (335)