The Nose Knows… or Does It?

August 18, 2024 1:48 PM

My partner just started testosterone shots and I swear I can detect a change in their bofy odor within a few hours of injection. They think I’m having a psychosomatic response based on my knowledge of the shot happening. Who’s right?

They’re doing 0.15 mL testosterone cypionate subcutaneous injections. I feel like their scent gets spicier/muskier within about two hours of getting the shot, and stays at a high clip for 24-48 hours before slowly fading out by the end of the week. Their skin feels warmer and oily for the first day too, as if some conversion byproduct is leaching out.

I’ve always had a sensitive sense of smell… I can tell when people are aroused or sick even when there aren’t obvious cues. I’ve had many trans and intersex friends over the years whose hormone fluctuations I can track by my nose. I can also usually tell when afab people have PCOS. Is this really so far-fetched? Can any scientists or medical experts weigh in? I’d love to see some data.

posted by lloquat to Science & Nature (10 answers total)

Is this a testable hypothesis? Like, could they randomly delay their shot a few hours one day without your knowledge, and then see if you still detect the change when you only think the shot happened?
posted by cubby at 1:55 PM on August 18

I don't understand why it would be farfetched. People smell changes in other people's bodies.

If you want to test it get some identical t-shirts to wear before and after injections.
posted by If only I had a penguin... at 2:38 PM on August 18

This is a known side effect - hormone levels increase, and as a result, the body produces more oil on the skin, you sweat more, and your body odor increases. If you had Googled this, you would have seen both significant scientific publications as well as first-person anecdotes.
posted by NotMyselfRightNow at 2:39 PM on August 18

Dogs are way better than humans at smelling stuff and they can detect hormones with ease. You must have an amazing sense of smell and I'd assume it is accurate.
posted by theora55 at 3:03 PM on August 18

Speaking as a trans woman, yes this is absolutely a thing, and widely recognised in the trans community.
posted by june_dodecahedron at 3:07 PM on August 18

Unless you're doing their shots, this is trivial to test. They shift around when they do their shot (time of day, day early or late) and don't tell you, you write down when you think their smell changed. Do this for like four weeks then compare notes.

The sort of scent changes you're describing are totally expected, though I don't recall anyone reporting them or their partner being anywhere near as sensitive to it as you're describing. I've never done injections, so I really can't comment on skin texture.
posted by hoyland at 4:28 PM on August 18

Oh for SURE hormones and lots of body things are smellable. My friend can smell insulin on people; I can smell adrenaline on people's breath and sweat, monthly hormone changes in certain women's sweat (I know it's accurate as they're close friends and romantic partners), and I can smell certain illnesses in people's sweat and breath, including dental cavities and infections - I once correctly diagnosed a bladder infection from smelling the warm air in the bathroom right after the person peed. A woman diagnosed her husband's Parkinson's by smell. Some human noses are pretty sensitive!
posted by nouvelle-personne at 4:43 PM on August 18

It's definitely a thing. When my trans masc partner started T, this trans femme absolutely noticed a change in how he smelled. It fades over time and becomes less noticeable/powerful.
posted by kokaku at 4:44 PM on August 18

Also, if this is regular hormone therapy, changing the timing of the shot won't matter. Over time, the T is changing the balance of sex hormones in the body overall, and that has long-term effects (ideally, right?).
posted by kokaku at 5:03 PM on August 18

I did google this extensively, and found lots of related research on links between olfaction, attraction and health. However I only saw a handful of anecdotes suggesting scent or texture might change in such a short window (hours, rather than days/weeks/months). That's what I'm curious about, the timing.

We'll run some experiments!
posted by lloquat at 5:15 PM on August 18