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158 herbs, nutrients, and compounds. What the science says, what tradition knew, and what to watch for. Founding members keep this running.

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GUT HEALTH

Bitter Orange

Citrus aurantium

also known as Seville orange, synephrine

Weak (modern uses) — and a real cardiovascular safety concern

Bitter Orange — Köhler 1887 botanical illustration

The peel of a sour orange variety, used as a digestive bitter in European and Chinese medicine for centuries. After ephedra was banned from US dietary supplements in 2004, bitter orange became a common replacement in weight-loss and energy products — and bitter orange has caused similar cardiovascular incidents. The traditional small culinary use is fine; the high-dose supplement use is not.

Long traditional culinary and medicinal use as a digestive bitter
Bitter orange peel is an ingredient in marmalade, Cointreau, and Curaçao — the food uses are completely safe
Traditional Chinese medicine use (zhi shi from immature fruit, zhi qiao from mature fruit) for digestive stagnation
Mild appetite-stimulating effect
Modern weight-loss claims around its synephrine content have not held up well in research

Synephrine and related compounds raise blood pressure and heart rate — bitter orange supplements have caused heart attacks, strokes, and at least one documented death

Skip with high blood pressure, heart disease, or arrhythmias

Skip with thyroid disease

Strong interaction with stimulant medications, caffeine, and other thermogenic supplements — additive cardiovascular risk

Strong interaction with MAOIs — can cause severe blood pressure spikes

Bitter orange peel inhibits the same liver enzyme as grapefruit, affecting medication metabolism

Skip during pregnancy and nursing

Skip with anxiety disorders

Stop two weeks before surgery

FDA has investigated multiple cardiovascular events tied to bitter orange supplements, particularly when combined with caffeine

NCCIH — Bitter Orange · MedlinePlus Herbs & Supplements · NIH NCCIH Herbs at a Glance

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