Fennel Seed Extract
Commonly used for
Digestive Health
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What is it? / Overview
Fennel has antispasmodic and carminative effects -- relaxing GI smooth muscle and helping expel gas -- and experimental data show it strengthens intestinal barrier function, supporting its traditional use for bloating and cramps. The strongest human signal is in infantile colic; adult efficacy data are mostly from combination products, not fennel alone.
How is it used? / Administration
Form: Fennel (Foeniculum vulgare) seed extract, oil, or tea
Typical dose studied: No single validated dose -- varies by preparation; adult trial data mostly comes from fennel-oil + curcumin combination products
Timing: After meals
Possible mild estrogenic activity is worth a caution in hormone-sensitive contexts, though the effect size in humans is not well established.
How well does it work? / Evidence
? Emerging / limited evidence
Who should avoid it?
Avoid with: Breastfeeding; Food Allergies
Interacts with: Estrogen-based hormone therapy -- theoretical additive estrogenic activity
Already taking it? Generally well tolerated; note the Food Allergies contraindication specifically covers Apiaceae-family (celery/carrot) sensitivity, since fennel is in that family.
Research & references
Das B et al. (2021). The Effect of a Fennel Seed Extract on the STAT Signaling and Intestinal Barrier Function. PLoS One. Annahazi A et al. (2025). Fennel Tea Has a Region-Specific Effect on the Motility of the Stomach. Neurogastroenterology and Motility.
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