Fun fact the brain actually filters the smell out. When the smell of your noses internals changes, or your brain stops filtering it for whatever reason (common during illness), it tends to smell putrid. Often described as a smell of "decay".
That's not even because the smell is that bad. It's just a mildly bad smell that happens to be right in your smell receptors.
Covid caused a funny phenomena with that too as it causes a heavy change in taste/smell perception.
Interesting, could you share more on how that works? Is it a neurological change or more of a physical "clogging"
There are a variety of ways in which our bodies attune to constant stimulus, in the case of neural stimulus, there are a variety of mechcanisms with the common goal of reducing activation of the neural pathway. You could have less receptors, more breakdown of the stimulating compound, increased cell activation treshold or downstream changes that similarly just reduce the ability for the signal to cause effects further along the chain.
Receptor or physical clogging generally (afaik) does not happen with substances we encounter normally, however it is a common tactic in pharmacology, where we might use a drug that binds to a receptor without effect and prevents the active compound from binding.
Or in the case of Succinylcholine, it binds, causes the normal action, but then prevents the normal molecule from binding and causing the action again - this is used to achieve rapid muscle paralysis and is both a poison as well as a common drug used for anesthesia.
Covid's "funny" phenomena is primarily due to the virus causing damage to the olfactory neurons and supporting cells in the nose. In rare cases it can permanently damage the neurons (which happened to me and my sister and our sense of smell still isn't the same as before, 2.5 years after catching covid). It's not that funny.
It's not all just negative tbh. I suffered from it myself and was an strict pescetarian before as I couldn't stand the taste of any meat besides fish.
Caught Covid and suddenly milk tastes like caramel and I started to enjoy the taste of beef and lamb. Coffee smells weird though, it triggers the same response in my brain as "A dog just pooped in the house two rooms over".
That last one is what annoys me. My sense of smell never relearned to distinguish those two things.
I suffered with it a lot, personally. Pretty much every food tasted different, and most of it was horrible for about 1 year (after the initial ~3 months of 0 smell). I lost a lot of weight because I just couldn't eat anything, everything had a horrible taste that I cannot compare to anything and I was really depressed about it. I started experimenting with vastly different foods that I was used to eating and that worked a bit. After about 1,5 years some tastes slowly started creeping back and it's still in progress. Some foods now just simply taste different to what they used to (but not bad), some still taste bad, and some taste exactly like I remember.
This whole thing was/is really depressing for me personally. I don't have any positives about it.
Share your source, otherwise this is just bullshit. I think it's bullshit.
Edit: I don't doubt the covid part. Maybe that causes weird reactions. It's been described to me as "different", rather than a loss of smell.
Edit 2: Still no source. Downvote all you want, you're still not convincing any scientifically minded individual that you're correct.
You can smell other people's mucous (not recommended). If you ever have been the primary care taker for a baby or small child you'd know what boogers smell like. Old boogers also start to decompose and the smell is faintly different. Sick mucous also smells different and worse. I could tell my nephews were sick with the flu by smelling them from ways away before noticing any other symptom. Sometimes I can smell that in public transport and it makes me figuratively run in the opposite direction of the sick person.
I appreciate discussions that differ from the basic, casual topics! It's a nice, different breeze!
