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.
kzrdude•Aug 24, 2026
Based on your new information, I think it would be good to test the effect of supplemenths vs supplemints.
tclancy•Aug 24, 2026
Please consider the fact there may be children reading before you do something like this again.
trueno•Aug 24, 2026
im bored and want to buy some peppermint sups. someone drop a brand and sell me on it in the marketplace of ideas
overtone1000•Aug 24, 2026
That is very accurate sphygmomanometry!
jeffnv•Aug 24, 2026
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!
rolisz•Aug 24, 2026
Maybe it helps with weight loss (I wish)
yumraj•Aug 24, 2026
It seems to aid in digestion, soothe upset stomach, so maybe it does.
leni536•Aug 24, 2026
It did help Mr Creosote.
ThePowerOfFuet•Aug 24, 2026
But it was just wafer-thin!
potatoking•Aug 24, 2026
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.
criddell•Aug 24, 2026
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?
debo_•Aug 24, 2026
On the topic of mass, I am certain your pedantic comment will be mass downvoted.
ktm5j•Aug 24, 2026
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.
bherms•Aug 24, 2026
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
samudrijan•Aug 24, 2026
Funniest thing today so far.
simondotau•Aug 24, 2026
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.
debo_•Aug 24, 2026
Unlike the anuses in government etc.
scorpioxy•Aug 25, 2026
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.
wahern•Aug 25, 2026
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.
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).
yumraj•Aug 25, 2026
I don’t think that’s peppermint. That’s pudina so spearmint. Mentha spicata.
vector_spaces•Aug 24, 2026
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.
>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.
samudrijan•Aug 24, 2026
Sit and drink pennyroyal tea,
I’m anemic royalty.
rshm•Aug 24, 2026
Also used as lactation reducing herb.
vector_spaces•Aug 24, 2026
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
r0ze-at-hn•Aug 24, 2026
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.
f33d5173•Aug 24, 2026
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.
crooked-v•Aug 24, 2026
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.
simondotau•Aug 24, 2026
As a bit of random speculation: improved digestion might reduce the “needy stomach” sensation associated with hunger.
joecool1029•Aug 25, 2026
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.
>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.’”
>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!"
NDizzle•Aug 24, 2026
This is my favorite soap, by far, for what it’s worth. The peppermint one, in fact. ALL ONE!
alastairr•Aug 24, 2026
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.
bryceacc•Aug 24, 2026
>50 µL of supplement diluted into 100 mL of water
pretty tiny amount of peppermint was consumed
jeffbee•Aug 24, 2026
That's enough to turn a whole barrel of water detectably minty.
HeyLaughingBoy•Aug 24, 2026
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.
Palomides•Aug 24, 2026
HN really upvotes some dumb medical articles, come on, n=20 about peppermint?
rozap•Aug 24, 2026
Silence, we have disruptive direct to consumer peptide startups that need to pump.
now we need a study of adding Peppermint oil into hybiscus tea.
SwellJoe•Aug 24, 2026
A Mediterranean place I used to eat at weekly served a hibiscus mint (spearmint, though) tea. Pretty nice.
cicko•Aug 24, 2026
I'll do a n=1 study on that
ChickeNES•Aug 24, 2026
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
pessimizer•Aug 24, 2026
If there's anything consistent about HN as long as I've been on it, it's that HN is orthorexic.
doublepg23•Aug 24, 2026
> orthorexic
New word of the day!
liveoneggs•Aug 24, 2026
herbal tea is good for you, it seems
SwellJoe•Aug 24, 2026
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.)
techteach00•Aug 24, 2026
Also works well for IBS. Popular brand name green box. Bit pricey.
catigula•Aug 24, 2026
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.
reilly3000•Aug 24, 2026
Aren’t people generally getting some via toothpaste?
simondotau•Aug 24, 2026
But do you spit or swallow?
garbageman•Aug 24, 2026
Whatever you want baby
Havoc•Aug 24, 2026
I need my porch painted and tradesmen are expensive
jrflo•Aug 24, 2026
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.
Lu2025•Aug 24, 2026
Well, mint tea does make me sleepy
profsummergig•Aug 24, 2026
So does it therefore reduce stress? Anyone?
Finnucane•Aug 25, 2026
Those old York's Peppermint Patty ads were on to something.
paimapi•Aug 24, 2026
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
Essential oils are quite versatile for self-experimentation; maybe one day the world will rediscover oilahuasca.
_heimdall•Aug 25, 2026
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.
17 Comments
I wonder if mentha arvensis has the same effect. Supplements vs mint tea would be another interesting thing to study in future.
The fascinating part is that your anal tissue has that level of sensitivity and insight.
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/
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.
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.
At least this study says the activity was reduced, not significantly though: https://www.sciencedirect.com/science/article/abs/pii/S02786...
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!"
pretty tiny amount of peppermint was consumed
FWIW, I had an Indian co-worker who took peppermint oil frequently and said that it was very good for his upset stomach.
New word of the day!
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