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Smell You Later: The Weird Science of How Sweat Attracts (thewalrus.ca)
141 points by herbertl on July 29, 2021 | hide | past | favorite | 70 comments



Who is #15???? After that good article, and that great lead up, we don't find out who is #15. I wonder if there is a follow up article. Definitely a fascinating field of study, we haven't even begun to understand. From mating, to enemy forming, to bullying, addiction, food analysis, sleeping, etc., there are so many potential topics to understand, depending on our research into smells.


> “Excerpted from The Joy of Sweat: The Strange Science of Perspiration by Sarah Everts”


about 20+ years ago I found myself single after a long term relationship.

I expermented with many things that would work in dating, one of the things I tried was having a shower earlier on in the day I was going out (about 3-5 hours before) and make sure I do some sort mild excercise - walking/ houswork etc after the shower (and only having a little smell/ perfume on me)

obviously all my observations were subjective, but it felt like it made a difference on my success rate - whether it was that or it raised my confidence I've no idea


A fraternity brother of mine used to do this too. I remember getting a full dissertation on why this worked (for him). He would go for a (light) run in the dress shirt he planned on wearing out later that night. shrug who knows if actually helped his dating life, but he swore by it.


Can relate. My current partner was a colleague and we had to literally work cloesly together. Something about the smell of her sweat activated the right brain function because it made me want more, as in 'let's procreate right now' and as wa later found out the feeling was mutual. That same smell on other women still has the same effect by the way; whereas I'm sometimes almost disgusted by people using a lot of perfume/deodorant.


It's better not to reference global variables in private functions.


Reminds me of a line from a book I read on perfumery: "The last ingredient in any perfume is your skin." A perfume will take on a different twist after being applied to one person or another.

In older times, when daily showering/hygiene wasn't super widespread, perfumes were designed to complement your natural aroma instead of covering it up. We call those natural body odors "animalic" scents. These days, we add in those types of scent into the perfume itself.


I know quite a few people who stopped regularly showering with soap and shampoo. They do it just on occasion and otherwise just use water. I can assure you that they do not smell bad. Consider doing so myself, and have heard it is better for skin and hair too. But I didn't look up any solid material on whether this is more healthy (a search will probably lead to a lot promoted science that urge me to use skin products).


I've taken a bit of a middle ground approach, partly out of laziness and partly because it just doesn't seem all that necessary.

I have to wash my hair daily otherwise I feel absolutely gross, and I'll also wash the private and smelly bits daily with soap, but otherwise I only use soap head to tow twice a week.

My partners have never seemed to notice or complain about any off smells although I realize being around someone for long periods of time can desensitize you so I've taken a few opportunities to ask my parents who would certainly be the first to tell me if I smell like crap and they've never had any complaints.

Anecdotally, every partner I've had has told me I have great skin. Hair stylists have also told me I have incredibly healthy hair - I've been using cheap Suave Essentials (the clear baby blue bottle) shampoo with no conditioner since I was a kid.


You’re actually not supposed to use soap on groin or anus:

https://www.google.com/amp/s/www.healthdirect.gov.au/amp/art...


> Keep the anal area clean by washing with water every day. Don’t use soaps as they will reduce the natural oils that protect the anus and may make the area dry and itchy. Use aqueous cream or a soap-free cleanser instead.

Non AMP link: https://www.healthdirect.gov.au/anal-care


Well that escalated quickly! ;-)

But seriously, an interesting topics. Thanks for the links!

I've never been a daily hair washer.

Or all over body soaper.



I sort of fell into the "nopoo" lifestyle. Things had evolved to the point that I was having constant problems with fungus that the anti-fungus shampoos could not control. Perhaps the fungus evolved. At one point I just said "screw it" and gave up on shampoo all together. Problem entirely solved, along with my dry hair problem. As a result I stopped bothering about body soap which generally made things better as well. Soap/shampoo for when I am actively dirty doesn't seem to break the spell. It is like I just need a break from soap/shampoo all the time.

No complaints so far...


Tried and failed, very embarassigly. Turns out not everything you read on the net is true :D

Last I heard there was some research on finding mixes of comensal bacteria that can replace the "stinky" ones. But currently, it's risky at best.

What I did get out of the experience is cutting on shampoo use. On hot summer days you can wash your hair as often as you want - but the extra washes should be water only, or at most conditioner.


I also tried this with the addition of some spray-on bacteria from motherdirt.com. A huge scam. I emailed one of the founders who prided herself on answering mails personally back when they first launched their "AO+" spray. Never got a response.

I don't understand these magical unicorns of people who just stop with all soap and shampoo and come out looking marvelous. I don't doubt they're special but I don't know what makes me poorly suited. I get rank and my hair gets terrible dandruff if I don't persist with these surfactants. And trust me, I've tried for a long time, to the detriment of everyone around me.


Know people who tried this.

They smelled very bad.

Also see lots of posts about Steve Jobs smelling bad


Since COVID, I stopped showering every day. I generally shower after working out, which is every other day. And I do this at the gym. Has saved me a lot on my water bill.

Of course if I do something strenuous at home and get really sweaty or dirty I will shower. There's no point in being disgustingly sweaty/smelly.


Works well. Just make sure to use a washcloth to exfoliate the dead skin. Although, I do use shampoo every other day, because I have super greasy Italian hair.


I don't like the perfumes so I use baby shampoo. I use it for everything. It's my shampoo, face wash, body wash, and shaving gel.


60% of the time, it works every time


Reminds me of:

https://smell.dating/


Or this (from: "A Fish Called Wanda"):

https://www.youtube.com/watch?v=xw5MxRhjudk


The fear of having any natural body odor in today's society is incredibly widespread. It's almost impossible to find information on the negative effects of our practices of putting ultra-scented substances on our skin via deodorants and perfumes, in our hair via shampoos, on our clothing via scented detergents, etc. Yet everywhere you look, there are vested corporate interests telling us that we stink, are repulsive in our natural state, and so on. This is why it's so difficult to find people willing to forgo these products, and then to admit it and report on the results. Sure, basic hygiene is important. Shower after working out. Brush your teeth. Comb your hair and rinse your scalp. I use to unquestioningly shampoo my hair every few days until I noticed I had to wash more and more frequently, as it started getting greasy quicker. In 2017 I decided to go cold turkey on using shampoo. The first few months were rough. But over time, my hair and scalp biome has normalized, and rinsing with warm water is enough to remove any grease build-up. My hair is also a lot healthier - less split ends and less dried out than before. Deodorant is a much more difficult beast to escape from. B.O. in the workplace is definitely worse than a greasy looking ponytail. However, with the lockdowns, I've been experimenting with skipping the deodorant. So far I can't say I like the results, but I wonder if it's again the kind of thing that takes a while to normalize. Either my nose will become numb to it, or the bacteria in the skin will calm down after being tampered with for so long. It's a little shocking to think I've been smearing a costly cocktail of chemicals on my pores for more than half my life, and barely even recognize my own scent. Crazy to think that we might be blocking an important subconscious source of information on the people in our lives.


Besides scented substances on our skin, I also cannot stand things like scented candles or scented air fresheners. The scents don't smell natural at all, are generally overpowering, and they occasionally give me headaches. I'd rather have good ventilation.


> This is why it's so difficult to find people willing to forgo these products

Pragmatically, we can't smell ourselves very well, and we tend to think it smells fine when we can. So how would you know we don't need to be insecure?

Our society is also uptight about this such that it's often treated as offensive and transgressive to do a very normal and polite thing (one would think) and point out to a close acquaintance or any friend, that well, they smell, since they probably don't know themselves.

In short, stop wearing so much deodorant and ask someone you can trust "do I smell okay?" (And not your spouse. Because same problem as yourself.) Oh so awkward. But how else will you learn? For myself, I was greatly over-estimating the scale of the miasma. Some clearly are underestimating theirs. Some data points would help us all.


I have experimented with it (with an honest partner to give me exterior feedback) and:

- no shampoo works for me, it has a difficult adaptation period but afterward it feels normal and my hair is healthy (nowadays I use a carefully selected shampoo about once a week)

- no soap also works but felts to weird to keep doing (nowadays I only use soap on sweaty areas, never on my face)

- no deodorant works and does not smell bad as long as your body is clean (nowadays I only use deodorant when I know I will be out and maybe active for too long to garantee that my body will stay clean)


I can only do no deodorant when I'm not eating simple carbs. Otherwise I stink quite badly. Something about simple carbs makes me nasty.


Chemicals, exercise, mood, and diet make a massive difference in body odor.

If I'm drinking, I smell terrible. If I'm taking my ADHD medicine, I smell terrible. If I don't exercise I smell terrible. If I eat only terrible food I smell somewhat bad.

If I abstain from pharmaceuticals and alcohol, exercise regularly and eat fairly well, then I generally don't really have to shower because the body odor smells fine.

But ADHD medication (Ritalin, amphetamine) absolutely make me smell horrid. No one wants to be around that.


This got me curious how modafinil, which I take medicinally for ADHD, is making me stink different.


I was once working on a micro site for some under eye highlighting roll-on, essential titanium dioxide suspended in various petrochemicals and emulsifiers. The premise of the ads was that bags under the eyes make you look old and tired, and I have to say all the weird beauty speak worked and I did start to wonder if I did indeed need their product that fixed a condition of being human that no-one noticed until their ad created this sense of lack in the people viewing it.


There have been some no-soap discussions on HN and I think a user called graeme described something similar, some years ago. I've tried not using shampoo but it was mainly rough and then I gave up (too early?). Anyway, I also wonder about possible benefits in not using detergents for skin biome (including a nicer odour), so soap is for my hands (interfaces with potential pathogens) and greasy stuff. The rest is easily cleaned with water.


There are real toxicological reasons not to use deodorant, especially the rub on variety. It is very easy to go old school, and just wash your armpits (sounds gross when writing it down,) but it is very effective. If your are sweaty in public, just find a sink and wash again. It takes 30 seconds. As with your shampoo experiment, the body becomes much cleaner when it's free to do what is supposed to do.


That works for some people but not others.

I once found myself in Shanghai minus my luggage that had contained my toiletries, including my deodorant - aluminum-free scented antiperspirant deodorant. From my searching (admittedly frustrated by poor Mandarin) no grocery, convenience store, or pharmacy in Shanghai stocks this product that's at every Walgreens and Meijer in the midwestern US. No, the people there don't smell bad at all. Apparently there's some kind of microbiome or skin oil in my pits that they don't have, or some beneficial thing that they do have which I don't.

But within a few hours, I stank profusely. My very patient and gracious host was unable to procure me any deodorant. I washed my pits repeatedly, but it only lasted an hour or less between washings. Later, when working from home, I tried going deodorant-free voluntarily: the transition to aluminum-free varieties was no big deal, the transition to deodorant free was an abject failure. I tried antibacterial soaps, non-antibacterial soaps, no soaps, mosturizers, even shaved my pits...only antiperspirant deodorant stops the stink for me.

Some people do smell human when they're sweaty, some try to mask it with perfumes but it's not necessary. Some don't have much of a perceptible smell at all. I smell repulsive.


I think going mostly soapless should work for everyone though. At least anecdotally from my experience, because it makes no difference. I'm like you, genetically predisposed to get smelly.

I use shampoo on the hair (every few days only since covid, pre covid every day though) and under the arms. I definitely have and never will use soap on my face for example or arms (unless I've been up to my elbows (literally) in the garden or something and I actually have to get something off.

Since covid I've noticed what was already happening before. When I go to the office I smell more, even with deodorant. It basically fails after lunch and I need to wash and reapply. Having more coffee makes it worse but going coffee less doesn't make it not happen. WFH causes way less stink even without deodorant. Though work days are definitely still worse than weekends or vacations.

I've been through all the different types of commercial deodorants. They usually work very well almost miraculously for a few weeks after which they make me stink even worse than before starting them. I've switched to home made deodorant now and apply it only when I go somewhere it matters.


It’s a known genetic trait:

https://en.wikipedia.org/wiki/ABCC11


The really fascinating bit about this one is it also changes your earwax. So it's quite easy to tell which gene you have, without a sniff test.


If ever again you get stuck in a country without deodorants, buy baking soda. It's an extremely potent deodorant (a little goes a long way).


Ever try crystal brand deodorant? It's literally just salt and inhibits bacterial growth when applied after cleaning


After a while I get natural body salts on the hairs of my armpits. And I can’t wash them away.


Some people do legitimately stink though.


Covid made me unable to smell body odor. I smell _something_, but it's very clearly not the same odors and it's completely flat - I can't tell the odor of different people apart for example, or tell apart the smell of a gym dressing room from that of used clothes.

Perhaps coincidentally, ever since I had covid I've had practically 0 libido. I used to have several ONS a month, now I haven't felt the need or interest for that for more than half a year.

I've been wondering if there's any relation...


Some mentions in the article remind me of the Nora Ephron movie "Michael" starring John Travolta as an archangel. Numerous women mention that he smells like cookies, pie, something pleasant from youth, etc


This is one of the best articles I've read in a while. The background story is entertaining, and the scientific part is relevant, well explained, and insightful.

My initial reaction to personal stories in science article is to expect trudging through, but I didn't feel bored for a second here.


Is anyone else really weirded out by the fact that the 'scent' you are attracted to is actually from the bacteria on the other person?


No more than thinking that as I look at someone's lovely skin, I'm looking directly at a body organ that sheds about 8 lbs a year and ends up as house dust.


Did the article actually conclude that though? I just read up until the point they were talking about strippers and lap dance tips being correlated with fertility and luteinizing hormone -- which doesn't seem to be about bacterial microbiomes.


Don't know which discussion on HN this was, but it was about the same book. Basically, each of us produces a varying amount of fat in our sweat and that leads to different bacterial biomes. The bacteria that metabolize the fat in the sweat are what actually produce the odors we recognize.


Well, your immune system, psychological state and general health is more determined your gut flora than anything you do otherwise (so eating the wrong things can also affect these).

You aren't just you. You are a system that includes bacteria on and in you.


We are just ecosystem hosts, they are the ones running the show.


"I've noticed you around. I find your microbiome very attractive. Would you... um..."


"My microbiome is signalling to me that it likes your microbiome."


Gut microbiota are increasingly being linked to immune system health.

Despite the old "disproportionally more bacterial cells than human cells" myth, we can still have twice as many bacterial cells in our bodies than human cells [1].

Humans are a commensal organism of many colonies of bacteria. Without them, we'd be in bad shape.

[1] https://www.nature.com/articles/nature.2016.19136


I wonder what sort of insights could be gathered from a large matrix of odor samples and preferences. Sounds like an almost perfect data set (nodes and edge weights) for some interesting research.


The East German secret police used smells to find suspects:

https://m.dw.com/en/the-stasi-had-a-giant-smell-register-of-...


That's a great article. Well, not great. Terrible. But a very interesting read. They did it then, and are doing it now. For those who want to know: Article describes how, today, government officials are storing smell samples of people, just in case. Just as the Stasi did in East Germany. Thanks.


Gives a new meaning to Gorky Park.

OK, now you're a little too gorky (== "bitter") for me.


My buddy's younger sister used to say she liked the smell of guys' balls.

I thought she was kidding the whole time I knew them. I wonder if this is what she meant.

I just wrote her off as a weirdo lol.


I’ve learned vocal tone range is a consistent across my mates, with higher pitched women never making the cut.

I wouldn’t be surprised if scent or some pheromone level is a major factor too.

This is in addition to form factor.


> Some pheromone

Interesting you brought up pheromones. There exists a whole cottage industry of companies selling pheromone scents used for the dating game. Most of it is snake oil though and they lack the proper studies needed to prove that the scents actually work


Are you talking about human relationships or some kind of device or program you are interacting with? Hard to tell from the way you are describing them here.


I’m repurposing form factor to be short hand of describing several desirable shapes and a lack of deviation from them. Since it is obvious to many people that share the same experience, I hope it catches on!


Seems like textbook objectification


Or people like what they like. Imagine that.


It reads to me more like technical specs for a sex doll or maybe dating simulator software, but I guess everyone is different.


> It reads to me more like technical specs for a sex doll or maybe dating simulator software

Most species have some selectivity used for determining mates, as well as reproductive strategies.

There is no shame in having a relationship with someone you find physically and mentally attractive.

After all, if children are the biggest investment in your life, may as well have them with someone you love.


I didn’t get the sense that the post I replied to was concerned with love or personality traits for their mating procedure as described. It was a list of physical attributes or tolerances like you might have for an object like a wrench or car.


Elements of attractiveness are merely entry points if you will.

Most western heterosexual women prefer men that are tall and have good facial symmetry. My gay friend told me he likes lumberjack types with heavy musculature. I personally prefer a taller woman with a good hip to waist ratio.

I wouldn't shame a woman for liking what she likes, nor would I shame my friend for his preferences. Nor should Cis hetero men be shamed for what they like. It is an individual decision.

There is a great deal more to relationship success beyond mere attractiveness. But, it has to start somewhere.


You are looking for a dissertation full of disclaimers to satisfy your sensitivities, following an article about a smell-dating event. This might be the moment where you take a step back and wonder why you are worried about this so much.


Probably just run into one too many incels on the internet with similar points of view that I am reading into this.




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