Pheromones by race

Pheromone Science Pheromone Theory & Molecules
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https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4724538/

An individual’s ethnicity has a significant impact on human axillary odor production with marked ethnic differences in volatile organic compounds (VOCs) among individuals of Caucasian, East Asian, and African-American descent.

a major contributor to axillary odor, E-3M2H, was significantly higher in African-Americans when compared to Caucasians and East Asians . The E-isomer (E3M2H) did vary with African-American > Caucasian > East Asian in the relative amounts produced.

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A similar trend also was observed for 3-hydroxy-3-methylhexanoic acid (3H3M) with African-American > Caucasian > East Asian in relative amounts observed. In addition, there were significant differences across ethnic groups in the number of individuals who produced detectable levels of 3H3M, with African-American > Caucasian > East Asian.

The ratio of E-to Z-isomers for 3M2H appears different from that seen for African-Americans and Caucasian donors. The E-to Z-isomer ratio for East Asian individuals favors the Z-isomer vs. the larger relative amount of the E-isomer seen in the other two donor groups

Volatile steroids, such as 5α-androst-16-en-3-one (androstenone) and 5α-androst-16-en-3β-ol (androstenol), originally were thought to play a role in axillary odor (Bird and Gower 1981), but later were found to be minor sensory and analytical contributors relative to the organic acids (Zeng et al. 1996a, b) in regard to axillary odor.

Organoleptic and analytical chemistry methodologies have revealed that axillary odor derives from a complex mixture of C2?C11 normal, branched, and unsaturated acids, with the main components being (E)-3-methyl-2-hexenoic acid (E-3M2H) (Pierce et al. 1995; Zeng et al. 1991, 1992, 1996a, b) and 3-hydroxy-3-methylhexanoic acid (3H3M) (Natsch et al. 2003), as well as volatile sulfur compounds, particularly (S)-3-methyl-3-sulfanylhexan-1-ol) (Hasegawa et al. 2004; Natsch et al. 2004; Troccaz et al. 2004). The latter sulfur-containing compounds often are present at very low levels but have high odor impact (i.e., low olfactory threshold).

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All of this is related to the odor differences among ethnicity and what contributes to human odor production and not whether the chemical signals that have effects on others are from these things that produce the odor or from the other things like androstenone, androstenol etc that also have been shown to be present in much smaller amounts as well.

Some more differences mentioned:

7-octenoic acid is also higher in african americans -> caucasian -> asian

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African-American donors produced slightly higher amounts of all straight-chain acids: acetic, propanoic, butyric, valeric, and hexanoic.

When branched chain acids (isobutyric, 2-methylbutyric, and isovaleric acid) were examined, Caucasian donors appeared to produce relatively higher amounts than both Asian and African-American donors.
Perhaps differences in dietary intake can account for this trend. The amino acids leucine and isoleucine are found in high levels in dairy products (Annigan 2014). The branched-chain volatile acids, isovaleric acid and 2-methylbutyric acid, stem from the metabolism of these two amino acids, respectively. East Asians and African-Americans experience higher levels of lactose intolerance than do Caucasians (ProCon.org 2010); hence we speculate that increased intake of dairy products by individuals of Caucasian descent results in increased levels of the branched chain amino acids in these individuals.

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Studies also have found the presence of a specific anosmia to both isomers of 3M2H (E and Z) and an olfactory threshold (of when you can smell it) for the E-isomer that is within an order of magnitude of that for androstenone.

In males from other studies, E3M2H and the c6 to c11 organic acids are present in far greater concentration then androstenone.
~357 ng/uL extract of E3M2H vs ~ 0.5 ng/uL extract of androstenone.

In female samples (past study) the straight chain acids were present in greater abundance than E3M2H. Androstenone was not seen in female extracts. Androstenol was present in far lower concentration then E3M2H or the other acids: ~150 ng/uL extract of E3M2H vs ~ 3.5 ng/u extract androstenol.

The z form (isomer) of 3M2H (Z3M2H) is also present in both genders, but is in a different ratio: 10:1 (E:Z) in males; 16:1 (E:Z) in females.

Studies have found that those with a strong unpleasant odor had a significantly higher number of bacteria and had marked differences in the type of bacteria. Every subject with a strong axillary odor had lipophilic diphtheroids (C. lipophilicus) present in high numbers was responsible for the most offensive notes.

The 7-octenoic acid that is present represents a compound with a high odor impact.