News & Views on Systemic Body Odor and Halitosis such as trimethylaminuria TMAU. If you have fecal odors or bowel odors it may be metabolic/systemic

16 November 2011

Why can't I smell my own body odor ?

The rule for almost all cases of body odor and/or halitosis is that usually the person emitting the smell cannot smell it themselves, so they do not know how to monitor it. Curiously, it also seems that 'loved ones' often cannot smell the person either, and possibly a small % of the population in general (my guess is 10-15%)

There are a few theories why this could be :

Specific genetic anosmia : This is where the person is thought to genetically be incapable of smelling certain odors (or be far less sensitive to the odors). Personally I don't think this is the case in 'fecal body odor', because I can smell feces. I just can't usually smell it when it is from my circulation.

Desensitized to the smell : The theory is the brain (or olfactory system ?) get used to a smell and therefore ignore it. It's possible but again I do not think this explains it.

People and carriers with the same genetic fault have lower sensitivity because the compounds are circulating and reducing the sensitivity of the olfactory system : This is the theory I think most likely correct. My guess is that humans are designed not to smell things that circulate in them normally. Perhaps due to an olfactory reason, or perhaps the brain ignores them. All humans smell to dogs, but we cannot smell most of the smells. However when someone has a genetic fault causing abnormal compounds to circulate, my guess is that normal people will at times detect it, whereas carriers and sufferers will not. Presumably even carriers will notice it when it passes a certain threshold. So when your parents or siblings say they cannot smell you, I believe them. Since I reckon perhaps 10-15% of the population may be carriers too (perhaps more), I'm guessing that potential partners are most likely to be in this group too (?)

On the upside it should mean that most 'sufferers' are 'odor free' among other sufferers and perhaps carriers too. Although perhaps this depends how severe the genetic mutation is. It seems to be a threshold/sensitivity issue, so perhaps severe cases could be smelt by mild cases.

I also think that if it is a different enzyme at fault, then a person will be able to smell another person. Or even ordinary body odor/halitosis, where again 'loved ones' and the sufferer cannot seem to smell the odor


Anonymous said...

A gamekeeper once told me a rabbit cannot smell his own hole (Warren) .

Get New Posts by Email

systemic BO/halitosis important links

MEBO Research malodor study 2016


FMO3 reference

Blog Archive

TMAU/FMO3 research

Systemic Body Odor links

email :

Do you have systemic body odor ?

FMO3 Survey Form

FMO3 DNA test result survey
for those who have FMO3 DNA tested
survey still OPEN

TMA blocker pill (links)

P&G - Cleveland press release aug 2015
1st mention of 'DMB pill' dec 2015
FMO3 DNA testing
Update Aug 17 :
Genos is back with it's EXOME test

Note :
Exome/Genome testing may be better option than single gene testing.

See this post : link

Note : Genos Exome Testing.

Exome testing is almost the same price now as single gene testing. Also Genos is consumer friendly, which standard DNA labs are not.

So the blog offer to test solely for FMO3 is almost obsolete, and so no longer offered.

Does Genos fully sequence FMO3 gene ?

At the moment it is not clear, but hoped this will become clear over the next few months

Note : possible 'wild west' way of testing FMO3
Use an ancestry dna site and rummage through the raw data

TMAU Webinar #5 : Preti et al