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Peppermint Oil (Enteric-Coated)

One of the few supplements with genuine meta-analytic support for IBS — peppermint oil beats placebo for global symptoms and abdominal pain, with a number needed to treat around 4. The main trade-off is heartburn, which enteric coating reduces but does not eliminate.

What the science says

  • Improves global IBS symptoms Strong evidence

    A 2022 systematic review and meta-analysis of 10 RCTs (n=1,030) found peppermint oil superior to placebo for persistent global IBS symptoms (RR of not improving 0.65), with a number needed to treat of about 4 — comparable to or better than most prescription IBS drugs. Effects held across formulations.

  • Reduces abdominal pain Strong evidence

    The same meta-analysis pooled 7 trials (n=891) and found significant benefit for abdominal pain (RR 0.76, NNT ≈ 7). Mechanistically this fits: menthol blocks L-type calcium channels in intestinal smooth muscle, acting as a direct antispasmodic.

  • Small-intestinal release works better than ileocolonic release Moderate evidence

    The largest single trial (Weerts, Gastroenterology 2020; n=190, 8 weeks) found small-intestinal-release peppermint oil improved abdominal pain response and relief endpoints, while a novel ileocolonic-release formulation did not — and the trial notably missed its primary FDA-defined responder endpoint. Formulation matters, and the effect is real but not overwhelming.

  • Helps functional dyspepsia (usually combined with caraway) Moderate evidence

    A meta-analysis of the proprietary peppermint-plus-caraway-oil combination (Menthacarin) found improvements in epigastric pain and postprandial distress in functional dyspepsia. Evidence for plain peppermint oil alone in dyspepsia is considerably weaker.

Dosage & safety

Studied dose180-225 mg of enteric-coated peppermint oil, 2-3 times daily, taken 30-60 minutes before meals, for 4-12 weeks. Trials most often used 182-225 mg three times daily. Enteric coating is essential — uncoated oil is absorbed in the stomach, causing reflux and delivering little to the intestine. Swallow whole; never chew or crush.
SafetyHeartburn and reflux are the dominant side effects (in meta-analysis, adverse events were significantly more common than placebo, RR ~1.6), along with anal or perianal burning, belching with a menthol taste, and nausea. Contraindicated or to be used cautiously in GERD and hiatal hernia — it relaxes the lower oesophageal sphincter. Avoid in gallstones, bile duct obstruction, severe liver disease and achlorhydria. Menthol inhibits CYP3A4 in vitro, so use caution with narrow-therapeutic-index CYP3A4 substrates (ciclosporin, some statins, felodipine). Do not give peppermint oil products to infants or young children — menthol can cause laryngospasm and apnoea. Antacids and PPIs can dissolve enteric coatings prematurely; separate doses by at least 2 hours. Peppermint oil is a licensed traditional herbal medicine for IBS in the UK and EU, and prescription-strength in some countries.

Scientific references

Where to buy

Mason Natural, Peppermint Oil, Enteric Coated, 50 mg, 90 Softgels

View on iHerb

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