Peppermint oil reduces blood pressure by 8.48 mmHg in small study | Hacker News Reader

Peppermint oil reduces blood pressure by 8.48 mmHg in small study

journals.plos.org

231 pointsbrandonb108 comments

Noticing that the waist circumference on average went down on the peppermint group (85.17 -> 84.61) while the placebo group it went up (88.33 -> 88.65)? Also the resting heart rate dropped for the peppermint group. My initial suspicion is that the peppermint group coincidentally was also the 'got in better shape' group. Maybe the peppermint helped, but for relatively small groups that also seem to be improving waist circumference and heart rates likely due to good diet and exercise, I'm not convinced the peppermint did jack shit. More investigation needed! Would be awesome if it helped though!

There has been some research on spearmint suggesting anti-androgen effects in PCOS, which is a bit unexpected to me as I wouldn't expect mint-family herbs to have much hormone modulating effect at all. I would imagine there to be similarities in profile between spearmint and peppermint so perhaps a related mechanism is involved, although I would probably expect the opposite outcome as a naive layperson. But I haven't closely evaluated the paper nor do I know whether there's been much else suggesting this

It is important to remember that herbs are difficult to study in this setting compared with isolated compounds -- likely because their pharmacological and chemical compositions are sensitive to many factors: hour and season of harvest, form consumed (raw powder, alcohol extract, cold water infusion, fat emulsion, hot water infusion, combustion, pyrolysis, essential oil), part consumed (leaf, root, flower, seed), among staggeringly many others. Anyone with experience consuming cannabis or coffee can probably testify to the above

Not to mention that the pharmacologically active compounds in many plants are far from being comprehensively understood, let alone their interactions and dynamics

This isn't to say that every claim about herbs is to be taken seriously. My point here is more that there is no good reason to dismiss the herb itself as a cause yet simply because it's an herb and a fairly mundane one at that. There are easy examples of herbs which have pronounced physiological effects, used for recreation, performance enhancement, as literal poison, to induce labor, to thin the blood -- among others.

https://pubmed.ncbi.nlm.nih.gov/19585478/

So spearmint is not peppermint. Peppermint (mentha pipereta in this study) inhibits CYP3A4 and CYP1A2. CYP1A2 is in the liver and if that is inhibited then estrogen will route down the CYP1B1 path so the ratio of the two metabolites 2-OHE1 v.s 4-OHE1 would be altered. For the PCOS (renamed to PMOS btw) if they start with elevated 2-OHE1 after the peppermint this could result in improve estrogen signaling because the now raised 4-OHE1 has much higher affinity than the 2-OHE1 for ESR1 (Era). ESR1 in particular is known for lowering blood pressure.

This particular path isn't that crazy, but it would only be for a subset of folk. From the study there is something simpler: menthol acts as a natural calcium-channel blocker, triggering vasodilation to reduce blood pressure.

There is something to aromatherapy. Essential oils are full of molecules that look like drugs and bind to GPCR receptors in the nose that head to the brain and have all sorts of effects, even if these molecules don't transport well in the body or cross the blood-brain barrier.

Peppermint as a scent is usually thought of as stimulating, raising heart rate and blood pressure. The lore, with some research supporting it, is that other oils that are more sedating can bring down blood pressure if you use them, say, in a diffuser.

https://pmc.ncbi.nlm.nih.gov/articles/PMC3521421/

I find the sensuality of Ylang Ylang to be distracting so I mixed in Lavender and got this wonderful floral smell that filled my office but an hour later I notice the sedation and I am nodding off and can't concentrate on work at all. It was like the scene in the Wizard of Oz where the Wicked Witch of the West put (most of) the protagonists to sleep with a field of scarlet poppies.

I thought I wrote this are first! This is how I think through things as well with Nutritional Genomics. However, the pathway is probably not the cause for the lower blood pressure. The tea is very high in Epicatechin gallate which is most likely reason for the lower blood pressure.

http://phenol-explorer.eu/contents/food/869

https://onlinelibrary.wiley.com/doi/full/10.1111/jch.70036

https://academic.oup.com/chemse/article-abstract/40/1/27/290...

Menthol is wild.

Lightly edited from Wikipedia:

"Menthol's [agonism of] the cold-sensitive Transient Receptor Potential cation channel subfamily M (melastatin) member 8 or TRPM8 receptors is responsible for the well-known cooling sensation it provokes.

Menthol's analgesic properties are mediated through a selective activation of κ-opioid receptors. Menthol blocks calcium channels and voltage-sensitive sodium channels, reducing neural activity that may stimulate muscles.

Some studies show that menthol acts as a GABAᴀ receptor positive allosteric modulator and increases GABAergic transmission in PAG neurons."

…and! Check this out:

"Menthol has anesthetic properties similar to though less potent than propofol, interacting with the same sites on the GABAᴀ receptor."

Propofol. PROPOFOL. The -ol in propofol is the -ol in menthol, haha.

"Menthol may also enhance the activity of glycine receptors and negatively modulate 5-HT3 receptors and nAChRs."

Aaaaand:

"Menthol also lowers blood pressure and antagonizes vasoconstriction through TRPM8 activation."

Peppermint is even more wild becasue while Menthol is a TRPM8 agonist (cold sensation), ECGC, also very high in peppermint, is a TRPV1 agonist (warm sensation), which has the opposite effect of TRPM8.

The EGCG is probably what is reducing the blood pressure.

Transient receptor potential vanilloid type 1 is vital for (−)-epigallocatechin-3-gallate mediated activation of endothelial nitric oxide synthase

https://onlinelibrary.wiley.com/doi/10.1002/mnfr.201400699

Cardioprotective and Anti-Hypertensive Effects of Epigallocatechin Gallate: Novel Insights Into Biological Evidence

https://onlinelibrary.wiley.com/doi/full/10.1111/jch.70036

Anything with EGCG in it causes me extreme bladder pain, even peppermint tea. While taking tons of Ricola cough drops (high in mentol) once when I had covid I found my bladder pain vanished. I then learned how the TRPV1 receptor is involved in my bladder pain.

https://www.nature.com/articles/s41598-018-24056-0

Exploding-head emoji reaction here, both generally and specifically. Thank you.

many things are wild, just menthol has been studied for the past 50yrs

Well said!!

My point was exactly the hope to indicate how much knowledge there exists. That's the truly wild thing. Or yeah, how unread most of it lays.

I'm familiar with drug interaction monographs and enjoy reading them. And I am somewhat comfortable with the organ/body functional pathways (I think that's what it's called) -- where can someone view/look at different pathways of the body as a resource?

Fuck.

This is what I sound like when I talk about analogue electronics, isn't it?

Thing is I know I could look all those terms up and learn enough to be dangerous in a subject you're clearly very good at.

>I wouldn't expect mint-family herbs to have much hormone modulating effect at all

Mints are closely related to pennyroyal (Mentha pulegium), which was traditionally (and dangerously because of toxicity) used as an abortifacient. Its mechanism of action is still unknown, so hormone modulating effects seem plausible to me.

By "mints" I meant the family lamiaceae, so pretty broadly which contains sages, rosemaries, basils, teak, verbena, and in hindsight of course contains examples like this which straddle medicine (depending on dosage and circumstances -- I'm not advocating it be used as such) and poison. Even if just restricting to the genus mentha apparently. Anyway good call

Sit and drink pennyroyal tea, I’m anemic royalty.

Also used as lactation reducing herb.

Peppermint is now familiar to most people as the ubiquitous taste of toothpaste, even moreso than candy, food, or drink.

If we cue university student volunteers on Toothpaste -> Selfcare -> Weightloss I wonder what happens.

I also wonder what placebo was used, and to what effect. The typical flavoring agent to make something peppermint-flavored is peppermint essential oil (or cornmint, spearmint, etc), and I don't know how you'd make it convincing without also including a bunch of hypothetically active compounds. The paper lists Schweppes Peppermint Cordial, without mint on the ingredients label. "Peppermint cordial" used as flavoring was historically 10% peppermint oil, and today the Schweppes product they cite just lists "flavourings" as ingredient.

Alcoholic beverages are not required to list their flavoring ingredients, so "without mint on the ingredients label" says literally nothing.

Because the FDA regulates beverages separately from food (or at least alcoholic ones - not sure where the dividing line lies), you can sell booze flavored with things that you cannot put in snacks.

Lead and live tapeworm eggs are still out, though - for now.

But weight/mass didn't change one bit (okay exaggeration, but not by much), so maybe peppermint helps relieve gas. Who knows? There's a lot that this data could mean, and no simple way to figure it out.

i actually had heard it helps w/ bloating/stomach issues online and took for a while and def noticed a debloating effect and less gas... obviously 1 anecdote, but I'd assume any slight waistline reduction is due to that. Also sidenote: pooping often made it feel like I put a breathmint... up... "there" lol

Not surprising, it’s what happens to capsaicin too. Something has to happen to the molecules/compounds you consume. Either your body discards them, stores them, or transforms them.

The fascinating part is that your anal tissue has that level of sensitivity and insight.

Unlike the anuses in government etc.

I thought on similar lines. Because I use it often for ibs i noticeably feel much better and I suspect the bp and heart rate reduction could be due to reduced gi effect on body

In my culture, that's the goto herbal drink for when you have a stomach ache due to indigestion or gas by the way. I don't know how or why they work but some of these things do work. The footnote here is that it is for pain/discomfort that would also go away by itself if untreated. It just speeds up the process and provides some comfort. For different kinds of pain/discomfort, a doctor needs to be consulted of course.

Mint stimulates release of bile, which can help digestion, especially of fats. I have gallstones and unfortunately recently learned first hand how powerful the effect is after eating a couple of leaves (two kinds, but I forget which) from a neighbor's garden.

Funniest thing today so far.

It's actually prescribed for that: https://www.nhs.uk/medicines/peppermint-oil/

It's a mild laxative on top of that.

I think they've pooped out the difference.

Peppermint oil has traditionally been used in India for digestion, so you may be on to something. I remember this particular brand growing up: https://www.amazon.com/clp/B001NQ7S9G (no relation).

I don’t think that’s peppermint. That’s pudina so spearmint. Mentha spicata.

Nothing but blood pressure and heart rate was significant, and heart rate only barely so. I wouldn't read anything into the other numbers. It was a 20 day study, you aren't going to get long term outcomes from that.

Peppermint oil is a known laxative, so I wonder if that made a difference

Yes, and looking at dietary data, the study says that there is no difference in their diets, but carbohydrate intake drop from 217g to 171g. I don’t see how that’s insignificant.

I'd think weight could be causal for hypertension result or sentiment over health measurement could have been causal for weight or the study could just be too small.

When you say weight, do you really mean obesity? And if you are talking about weight, is it likely that people who live in low gravity environments will have fewer hypertension problems?

On the topic of mass, I am certain your pedantic comment will be mass downvoted.

I just thought it was interesting to consider how blood pressure might be related to gravity.

I just felt like making a mass pun.

I'm wondering if caffeine was accounted for in this. One thing I seem to recall is peppermint tea has some inhibition of CYP1A2. I notice it's missing from the wikipedia page now, so maybe this was a flawed study or something... figured I'd mention in case anyone else knows.

At least this study says the activity was reduced, not significantly though: https://www.sciencedirect.com/science/article/abs/pii/S02786...

Wild-ass guess: maybe the aftertaste of peppermint oil twice daily leaves people who are already unhealthy wanting to snack less, leading to minor weight loss.

As a bit of random speculation: improved digestion might reduce the “needy stomach” sensation associated with hunger.

It is a 0.7% drop, so very likely to not be significant unfortunately.

8/130 is ~ 6%

That is significant.

Of course, you would have to do a real study to see side effects versus current blood pressure medication, but if there is no real harm in peppermint, the 6% drop over an adult lifetime might make a large difference in vascular health.

I was talking about the waistline drop that the OP mentionned (85.17 -> 84.61).

I wouldn't put my hopes up that peppermint oil has anything to do with it.

Maybe it helps with weight loss (I wish)

It seems to aid in digestion, soothe upset stomach, so maybe it does.

It did help Mr Creosote.

But it was just wafer-thin!

I think its reducing bloating.

Whenever I see a study like this I assume that the researchers won the p<0.05 lottery

If you've tried 20 things, you've probably won that lottery. It's an easy lottery to win.

I think that's more than likely here as "placebo" was literally this peppermint cordial [1].

They say it doesn't have peppermint oil in it... but it does list "flavorings" and I don't know how you make something taste like peppermint without using peppermint (or why you wouldn't).

The other possible explanation is 1 group is basically drinking an extra 200ml of water with a microscopic amount of peppermint oil, and the other group is drinking an extra 200ml of sugar water. The researchers may have literally just stumbled on the fact that more water and less soda has positive health impacts.

[1] https://www.tesco.com/shop/en-GB/products/254854798

Classic xkcd on this topic https://xkcd.com/882/

Very likely. If they really wanted to make the results a bit stronger, they could at least have switched the two groups after 20 days.

a single RCT of 40 people is about middle-of-the-range when it comes the hierarchy of evidence and is at best a 'that's neat, I'll wait a few years for there to be more studies' if you don't want to do any more thinking about it, a 'I need to see it in context of other studies' if you want a lot of work, or a 'I sure hope there's a meta/review' if you don't have the time but still want to remain skeptical

that said, there is a GRADE-assessed systematic review and meta on mint (PMC11587584) and this linked study's results are 7x the pooled effect size (SBP -8.5mmHg vs -1.2mmHg) of the other RCTs. the review also concludes that more high quality RCTs are needed before anything approaching clinical significance

the wildly disproportionate effect size indicates to me that this is one going to be one of those outlier studies that future reviewers will either likely omit or clearly state that it is an outlier result and if they're super duper honest they'll provide the new pooled results with and without this outlier study

There are two types of peppermint supplements being sold: mentha pipereta that this study looked at, and mentha arvensis.

I wonder if mentha arvensis has the same effect. Supplements vs mint tea would be another interesting thing to study in future.

Based on your new information, I think it would be good to test the effect of supplemenths vs supplemints.

Please consider the fact there may be children reading before you do something like this again.

im bored and want to buy some peppermint sups. someone drop a brand and sell me on it in the marketplace of ideas

Garbage study.

The placebo was literally peppermint oil (they say what it is in the study). [1]

They claim it didn't have peppermint oil in it because it's not listed in the ingredients... but the ingredients have a catch all "flavorings" listed.

I highly doubt Coca Cola is getting a peppermint flavor by using anything other than peppermint oil. It's an incredibly cheap and easy oil to extract.

So you had 2 groups drinking roughly the same thing and one did better than the other. The only real difference is one got sugar water and the test group got unsweetened water.

[1] https://www.tesco.com/shop/en-GB/products/254854798

Fun fact: in Soviet Union a common drug which people believe might reduce chance of a heart attack or stroke in high-stress/panic situation was Validol.

What people don't know is that it was just peppermint oil + glucose. I.e. a mint candy in a pill form.

Perhaps it actually did help people just acting as a placebo / distracting from their panic. "I did something now I should get better".

But a concept of a panic attack was not widely known. I guess doctors believed it's easier to prescribe Validol which "prevents heart attack" than to explain people that their panic attack symptoms are caused by their brain

The funny thing is, I've read countless meta-analyses on various mainstream drugs, where total n=hundreds of thousands, and I still don't know if they work at all or not.

Ceylon cinnamon also helps lower blood pressure https://www.webmd.com/diet/health-benefits-ceylon-cinnamon

it's 2026, better sources than webmd exist: https://www.supplementdex.com/ or examine.com

That is very accurate sphygmomanometry!

I'm guessing that this number is the result of the average of "x" people in the study, and not an individual measurement. But, yeah, I see what that looks like.

Doctor Bronner was right!

Peppermint - Pure-Castile Magic Soap: Cool, Refresh, and Awaken with Invigorating Peppermint

https://www.drbronner.com/products/peppermint-pure-castile-l...

Dr. Bronner invented the peppermint oil soap for soiled diapers

https://www.sandiegoreader.com/news/1978/nov/02/cover-look-f...

Created in California: How Dr. Bronner’s became the soap for every subculture

https://www.latimes.com/business/story/2023-07-12/dr-bronner...

>Perhaps inspired by that experimental ethos, customers have discovered their own unusual uses in the years since Emanuel started mixing gallons of peppermint castile soap out of his Pershing Square tenement apartment in 1948. [...]

>David, Mike and Lisa Bronner grew up in Glendale, not giving much thought to the prospect of one day taking over the family business and generally regarding their grandfather as a bewildering figure.

>“My granddad was always talking about uniting ‘Spaceship Earth,’ and it was kind of sailing over our heads,” David said.

>“He’d be talking to us as if we were all PhD students in religious studies,” Mike said of visits to Emanuel’s home when the siblings were in elementary school. “He was blind, and every once in a while he would say, ‘Are you there?’ and we’d be like, “All-one, Grandpa!’ And he’d be like, ‘Very good. OK, I want you to recite the peppermint bottle.’”

Lisa Bronner: The Poetry of the Lavender Label

https://www.lisabronner.com/the-poetry-of-the-lavender-label

>The label on the quart size of the Lavender Pure-Castile Magic Soap holds the greatest insight for me into his motivations and goals. The Peppermint label records the tenets of his Moral ABC, his guidelines for humanity to find unity and a path forward. But it is the Lavender quart that hosts his poetry, and in that I see his heart. [...]

>"To keep my health! To do my work! To love, to live!"

>"Great peace is found in little busyness."

>"Work well yourself and work for all."

>"Til we rally, raise, unite!"

>"All-One-God-Faith, All-One! Unite!"

>"Lives of great men all remind us we can make our lives sublime."

>"Life is real! Life is earnest! And the grave is not its goal."

>"Let us then be up and doing ... still achieving, still pursuing"

>"In all we do, let us be generous, fair & loving to Spaceship Earth and all its inhabitants."

>"We're ALL-ONE OR NONE! ALL-ONE!"

This study compared a group that drank peppermint oil against a group that drank peppermint oil.

These researchers picked a placebo that was the thing they were trying to test. The dingdongs didn't think that "flavorings" could include peppermint.

So I'd hold off on singing the praises of peppermint as this is a pretty obvious flaw to the study.

This is the "placebo": https://www.tesco.com/shop/en-GB/products/254854798

This is my favorite soap, by far, for what it’s worth. The peppermint one, in fact. ALL ONE!

N=40. No idea why one would release such bullshit.

The worst part will be the idiotic news outlets publishing the stupid headline followed by the pseudoscience peddlers pushing peppermint oil supplements onto an ever-increasing boomer population by AI-generated Instagram ads. Lovely times we live in.

Even worse, the placebo group drank peppermint cordial. The researchers are arguing there is no peppermint oil in it because it's not a listed ingredient, but the listed ingredients have "flavorings". Which, I'd be shocked if it weren't peppermint oil.

This is the "placebo" they used [1]

[1] https://www.tesco.com/shop/en-GB/products/254854798

Publish or perish mentality + difficulty funding a larger study is why this gets published. There's nothing particularly wrong with it as an exploratory study, the big problem is the lack of incentive to try to reproduce the results and publish the inevitable null result.

I wonder if the benefits could be seen to some extent with peppermint tea as well. I generally drink a cup daily because aside from just being relaxing I find it helps acne or other skin inflammation calm down faster.

Maybe because it suppresses/modulates certain hormones? I'd be careful ...

https://www.sciencedirect.com/science/article/pii/S009042950...

> We performed this study because of major complaints in our area from men about the adverse effects of these herbs on male reproductive function.

I'm not personally concerned with male reproductive function, but have looked into the hormonal effects in women as well. Some have been beneficial when peppermint is ingested in appropriate amounts. Everything in moderation.

Peppermint is also very helpful for headaches and nausea in my experience. I'll smell some peppermint oil or put a drop on my upper lip, headaches and nausea go away pretty soon after.

I grew up sailing on the Chesapeake, and we used it for seasickness.

Maybe we can add some licorice root to balance the effect.

Aren’t people generally getting some via toothpaste?

But do you spit or swallow?

Whatever you want baby

I need my porch painted and tradesmen are expensive

So does it therefore reduce stress? Anyone?

Those old York's Peppermint Patty ads were on to something.

Peppermint group N=20. Mkay. 2 of those lost to followup, one because they didn't like the taste (control group got peppermint cordial). The result might be real but needs followup before we all starting gulping down peppermint oil.

>50 µL of supplement diluted into 100 mL of water

pretty tiny amount of peppermint was consumed

I was surprised by this too. From a background in writing code to control precision pumps, I have a good idea of what 50 µL looks like and it seemed like an awfully small amount. But I don't know how concentrated the oil is.

FWIW, I had an Indian co-worker who took peppermint oil frequently and said that it was very good for his upset stomach.

That's enough to turn a whole barrel of water detectably minty.

> The result might be real

How could they be? The peppermint cordial almost certainly contains peppermint oil!

The authors chose it because it wasn't explicitly listed on the ingredients list, but what was listed was "flavorings". I highly doubt coca cola used anything other than peppermint oil to flavor a peppermint drink. That would be bizarre to say the least.

HN really upvotes some dumb medical articles, come on, n=20 about peppermint?

I've got an n=65 about hibiscus and blood pressure, which has been better well known for awhile. https://www.ars.usda.gov/news-events/news/research-news/2008...

now we need a study of adding Peppermint oil into hybiscus tea.

A Mediterranean place I used to eat at weekly served a hibiscus mint (spearmint, though) tea. Pretty nice.

I'll do a n=1 study on that

Silence, we have disruptive direct to consumer peptide startups that need to pump.

do the peptides have n < 20?

cuz if so they may have more reason to sell than the bloody mint oil

Doesn't it make sense to run a small trial before running a big trial?

Also, peppermint oil is unpatentable. Neither Merck nor Novo Nordisk can hope to make billions from it, and without the profit motive, the list of institutions with both the budget and the will to fund a 500+ participant study is pretty short. This might be the best we can get.

And yes, I get that a small trial has less of a value...

If there's anything consistent about HN as long as I've been on it, it's that HN is orthorexic.

> orthorexic

New word of the day!

Nah, been around a while, now.

From PLOS One as well! I remember in college, I was taking a bio class that taught how to read journal articles...and a psych class that was assigning them. Psych class assigned almost solely PLOS One articles...which didn't survive the criticism I was being taught in the bio class lmao

Well, mint tea does make me sleepy

Essential oils are quite versatile for self-experimentation; maybe one day the world will rediscover oilahuasca.

Also works well for IBS. Popular brand name green box. Bit pricey.

Another thing you should do.

How do people even become like 60-70 or 80 around me without all this magic?

tztztzt

A small, traumatized little part of me is envisioning a whole new aisle of "Heart Healthy" peppermint ice cream products appearing in every store, holiday decorations going up, and speakers blaring Christmas carols a week before Labor Day.

/s?

herbal tea is good for you, it seems

This study did not involve tea. Do you have links to studies showing herbal tea has similar effect? (Sincere question, I drink a lot of peppermint tea for its mild decongestant effects.)

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