Anthropogenic Aroma Compounds

aka Human Body Odor

aka apocrine bromhidrosis, axillary osmidrosis

aka Is that Me [I Smell]?

Body odor network graph

Sweat doesn't smell, per se; what smells is the metabolism of skin flora. These are colonies of bacteria that live on your armpits, but can also be found around the areola, anogenital, and navel regions.

Kids don't smell the same as adults, because the bacteria haven't colonized their bodies yet. Old people, it seems, smell different because they produce a chemical referred to as, simply, "old people smell" (see below: trans-2-Nonenal).

Below are some aroma compounds produced by the human body, via either sweat or urine:

Methyl hexanoate

ethereal, pineapple

Methyl octanoate

citurs-like, fruity, green-like

Methyl nonanoate

coconut

Methyl decanoate

oily, fruity, wine-like

all methyl -noates

fatty acid esters; found in human sweat, possibly related to odor preference mate selection; some share the same chemical formula with Propyl hexanoate aka propyl caproate, ethyl heptanoate, butyl pentanoate; scent of propyl hexanoate described as blackberries, pineapple, cheese or wine

4-Hydroxybutanoic acid lactone

caramel; perhaps related to Hydroxybutyric acid (GHB) -

produced as a result of fermentation, and so is found in small quantities in some beers and wines; structurally related to the ketone body beta-hydroxybutyrate, although that is technically a carboxylic acid; perhaps related to diabetes and hangovers

Nonanal

lemon, lime, orange, oily, rose, apple, coconut, grape, grapefruit, melon, peach, meaty, nutty, vegetable-like, waxy; aka Nonanaldehyde, pelargonaldehyde; an alkyl aldehyde; produced by the human body and attracts mosquitos; responsible for the “smell of metal” along w decanal and the main component Oct-1-en-3-one (1-octen-3-one)

Acetone

ethereal, apple; propanone; active ingredient in nail polish remover and paint thinner; normally present in blood and urine. People with diabetes produce it in larger amounts; it is the ketone produced by the body in the metabolism of fats; produced by the liver whenever the liver has to produce glucose at a very high rate, such as in diabetes

Vanillic acid

chocolate, creamy, grape, nutty, wine-like

4-hydroxy-3-methoxybenzoic acid; a dihydroxybenzoic acid derivative; oxidized form of vanillin; found in the root of Angelica sinensis, and Açaí oil Euterpe oleracea; main natural phenol in argan oil; found in wine and vinegar; main catechins metabolites found in humans after consumption of green tea infusions

Butyric acid

cheese; systematic name butanoic acid; found in milk and as a product of anaerobic fermentation (including in the colon and as body odor); fishing bait additive, component of vomit, used in stink bombs; fermentation of butyric acid is also found as a hexyl ester hexyl butyrate in the oil of Heracleum giganteum (a type of hogweed) and as the octyl ester octyl butyrate in parsnip (Pastinaca sativa)

Indole

animal-like, chocolate, honey, vanilla, musty, earthy, butter, cheese, fatty, jasmine, grape, vegetable-like, wine-like; an amine; aromatic heterocyclic organic compound; produced by bacteria as a degradation product of the amino acid tryptophan; occurs naturally in human feces and coal tar; intense fecal odor; flowery smell concentrations; natural jasmine oil contains around 2.5% of indole

Skatole

Floral; 3-methylindole; belongs to the indole family; occurs naturally in feces (it is produced from tryptophan in the mammalian digestive tract) and coal tar; strong fecal odor; flowery smell in low concentrations; found in orange blossoms, jasmine, and Ziziphus mauritiana; used by U.S. military in its non-lethal weaponry

Jasmine

floral; shrub of genus Jasminum; chemical constituents include methyl anthranilate, indole, benzyl alcohol, linalool, and skatole

Fumaric acid

sour; found in fumitory (Fumaria officinalis), bolete mushrooms (specifically Boletus fomentarius var. pseudo-igniarius), lichen, and Iceland moss; Human skin naturally produces fumaric acid when exposed to sunlight; product of the urea cycle; provides sourness; a Trans-Butenedioic Acid

Lauric acid

fatty; systematically: dodecanoic acid; saturated fatty acid; faint odor of bay oil or soap; as a component of triglycerides, comprises about half of the fatty acid content in coconut oil, laurel oil, and in palm kernel oil; found in human breast milk (6.2% of total fat), cow's milk (2.9%), and goat's milk (3.1%)

Isovaleric acid

animal-like, cheese; a fatty acid; strong pungent cheesy or sweaty smell; major component of the cause of unpleasant foot odor, as it is produced by skin bacteria Staphylococcus epidermidis (which is also present in several strong cheese types) metabolizing leucine; volatile esters have pleasing scents; produced by the oxidation of hop resins in beer, where it is seen as a defect

Phenethyl acetate

balsamic, floral, citrus, fruity, wine-like; Part of the characteristic odor of Camembert cheese, along w biacetyl (buttery flavoring for popcorn), 3-methylbutanal, methional (degradation product of methionine), 1-octen-3-ol and 1-octen-3-one (degradation products of fats), 2-undecanone, decalactone

trans-2-Nonenal

fatty, waxy; 4-Hydroxynonenal; a,ß-unsaturated hydroxyalkenal; found throughout animal tissues; found in Clitopilus prunulus, commonly known as the miller or the sweetbread mushroom; cucumber odor of this species has been attributed to trans-2-nonenal, which is present at a concentration of 17 µg per gram of crushed tissue; see 2-Nonenal: an unsaturated aldehyde; with human body odor alterations during aging, old-person smell, smell of old books, aged beer and buckwheat

Oleic acid, natural

fatty; a monosaturated fatty acid; occurs naturally in various animal and vegetable fats and oils; monounsaturated omega-9 fatty acid; term related to olive, predominantly composed of oleic acid; makes up 59-75% of pecan oil, 61% of canola oil, 36-67% of peanut oil, 60% of macadamia oil, 20-85% of sunflower oil (the latter in the high oleic variant), 15-20% of grape seed oil, sea buckthorn oil, and sesame oil, and 14% of poppyseed oil; constituting 37 to 56% of chicken and turkey fat and 44 to 47% of lard; most abundant fatty acid in human adipose tissue; emitted by the decaying corpses of a number of insects to signal removal of dead bodies

Trimethylamine solution

oily, fishy, meaty; tertiary amine; strong "fishy" odor in low concentrations and an ammonia-like odor at higher concentrations; Trimethylaminuria is a genetic disorder in which the body is unable to metabolize trimethylamine from food sources, Patients develop a characteristic fish odour of their sweat, urine, and breath after the consumption of choline-rich foods

p-Cresol

medicinal; major component in pig odor, human sweat; traditionally extracted from coal tar

trans-3-Methyl-2-hexenoic acid

(TMHA) is an unsaturated short-chain fatty acid that occurs in sweat secreted by the axillary apocrine glands of Caucasians and some Asians.[1]

Hexanoic acids such as TMHA have an hircine odor. Of the fatty acids contributing to Caucasian men's axillary (underarm) odor, TMHA has the most prominent odor.

*Information taken from Sigma Aldrich Flavor and Fragrance Catalog, 2013.

**wiki-scraped description fragments are meant for contextualization/disambiguation only.

***see this chart for visualization of the body odor smell network:  fusiontables

"The Smell of Ammonia in Your Sweat"

When too much nitrogen is present in your system, your body depends on the kidneys to process the excess nitrogen. This process creates urea, which can then be expelled through your urine. However, when there is too much for the kidneys to even process, then the excess nitrogen is secreted as ammonia through your sweat. When you exercise and sweat at a greater rate than normal, enough ammonia escapes for you to actually smell it…(or when your kidneys are under stress, thus processing less, and sending more through as sweat?).