Enteric-coated peppermint oil

The short version

What it does It relaxes the smooth muscle of the gut. On diagnosed irritable bowel, it improves global symptoms — pain and bloating — with the best level of evidence in the digestion aisle.

What it does not do It treats neither simple constipation, nor a food intolerance, nor slow transit. And it makes reflux worse: if you get acid repeats, it is not for you.

What the studies say

Seven randomised placebo-controlled trials, pooled by Alammar: patients on enteric-coated peppermint oil were about 2.4 times more likely to see their global symptoms improve. All seven trials point in the same direction, without exception: that is unusual, and it strengthens the result. The mechanism is known: menthol blocks calcium channels in intestinal smooth muscle, which relaxes.

The trials remain small — about 250 people in each group — and are in patients with diagnosed irritable bowel, not in general digestive complaints. “2.4 times more often” does not tell you how many extra people are actually relieved. In this condition many already improve on placebo, so the real gain is more modest than the figure suggests.

If a doctor has diagnosed you with irritable bowel, this is the first product to try — before the probiotic, and with better data than it. If your problem is slow transit with no diagnosis, it is psyllium.

How to take it

Relevant in diagnosed irritable bowel, with pain and bloating. Pointless for simple constipation. To be ruled out in reflux, hiatus hernia or gallstones.

450 to 750 mg a day, split into two or three doses, 30 to 60 minutes BEFORE meals. The capsule must be swallowed whole, never opened or chewed: the whole point is that the coating holds until the intestine. Allow four weeks.

Judge at four weeks on pain and bloating, not on transit. A cooling anal sensation is common and harmless. Minty repeats mean the coating gave way too early: change brand or move further from the meal.

What is inside

Mentha piperita essential oil, standardised for menthol, in an enteric-coated capsule that resists stomach acid and dissolves in the small intestine. The coating is the heart of the product, not a manufacturing detail.

Look explicitly for “enteric-coated” and a stated oil content per capsule. Some brands add delayed release towards the ileum, said to be more effective — that is suggested by comparison across trials, not demonstrated head to head. An essential oil sold in a bottle to dilute is NOT the same product and has none of the data above.

Non-enteric capsules, which guarantee acid reflux. Contraindicated in gastro-oesophageal reflux, hiatus hernia, biliary obstruction, and in young children.

Cautions

• Gastro-oesophageal reflux and hiatus hernia
• Biliary obstruction
• Children under 8