What Is Peppermint Oil?
How does peppermint oil work in our body?
Although peppermint contains numerous components, the main active ingredient in PMO is thought to be menthol, and primarily works by blocking calcium channel receptors to reduce muscle spasms.34
There is evidence to suggest that PMO may also have anti-inflammatory, antimicrobial / antifungal, and visceral pain-relieving properties, as well as possible effects on behavior such as mood and attention.5
Does Peppermint Oil Help IBS?
Short answer? It just might! But as always, it’s complicated.
Systematic reviews and meta-analyses on PMO and IBS throughout the years have consistently reported that supplementation results in statistically significant improvements in IBS symptoms.6789
In the most recent meta-analysis, published in 2018, pooled data from seven studies on global IBS symptoms and six studies on abdominal pain showed statistically significant improvements with PMO supplementation compared to placebo, with a number needed to treat (NNT) of 3 for global IBS symptoms and 4 for abdominal pain.8
So it works, right?! Case closed? Time to call it a day? Well, not so fast. The truth is, while all the meta-analyses that have been done so far have been in agreement, individual study results have not exactly been unanimous.
Two recent published studies, in particular, put into question the extent to which PMO is actually helping.
In a 2020 study done in the Netherlands, 10PMO did not result in statistically significant decreases in abdominal pain and overall IBS symptom relief compared to placebo, when measuring symptom relief criteria defined by the FDA and European Medicines Agency (EMA) guidelines.
However, there were significant improvements in discomfort, IBS severity, and abdominal pain using different measurement methods. Why the conflicting results even within the same study?
Well, this gets into the debate as to which outcome measures researchers use in studies to see if an intervention is working. On one hand using more rigorous criteria helps us feel more confident that people will see a meaningful improvement; however, we also don’t want to make it so hard to show improvement that we end up tossing out a bunch of interventions that can be of help to people.
In this study, what seems likely is that the researchers underestimated how much harder it would be to show statistical significance with the FDA and EMA guidelines, and simply didn’t recruit enough people.1112
In a second recent study published in 2021, although PMO supplementation resulted in significant symptom improvements using the more common IBS Symptom Severity Score (IBS-SSS) criteria, the results were not statistically significant when compared to the placebo group.13
Why the absence of significant benefit over placebo?
Well, of course, we have to consider the reality that PMO might not be quite as effective as once thought.
However, there was something peculiar about this study that is worth mentioning. The authors noticed that the placebo response in their trial was a lot bigger than what is usually seen in other trials in IBS patients. They also noted that this study was nested within a larger study specifically looking at placebo responses in IBS patients, and that it’s possible their recruitment messaging may have accidentally resulted in a participant group extra prone to the placebo effect.
The takeaway from these studies
How To Take Peppermint Oil For IBS
How much to take (dosing)
Enteric coated capsules
It is recommended to choose a product that is enteric coated, so it actually reaches the small intestine before being released and will minimize the chance of getting any heartburn.
Safety & side effects of peppermint oil
Taken orally, PMO is considered safe by the Food and Drug Administration (FDA) 14, as there have been very few adverse events throughout the research that has been done over the years.8
- The few adverse events that have been reported in studies were mild and didn’t last long.
- One of the most common side effects of taking PMO is heartburn, which is thought to be helped by enteric-coated formulations. This coating helps to delay the PMO release in order to target the small intestine.
- Other potential but uncommon side effects may include diarrhea, nausea, vomiting, allergic reactions, asthma exacerbation, and atrial fibrillation15.
- There has been a concern for liver toxicity in rat studies because of a component of peppermint known as pulegone, however the standard dosing of PMO is far below the amount that regulatory agencies have deemed as potentially problematic.516