Black men have more testosterone than white men

 

Testosterone is primarily responsible for male sexual development, which includes testicular descent, spermatogenesis, enlargement of the penis and testes, and increased libido (sexual desire).

The fetus develops with the testes still inside the belly, and they usually begin to descend into the scrotum around 7 months of gestation, when the testes begin to secrete reasonable amounts of testosterone.

If a male child is born with normal undescended testicles that do not descend at 4 to 6 months of age, administering testosterone can help the testes descend through the inguinal canals.

Testosterone is also involved in the regulation of secondary male characteristics, which are responsible for masculinity, such as voice deepening, muscle growth, pubertal growth, and skeletal muscle growth in addition to stimulating protein synthesis (GN Nassar et al. al, 2022).

Difference in testosterone levels between blacks and whites

In 1986, a study was carried out to find out if there was variation between testosterone levels according to race. The result revealed that black men have, on average, 20% more testosterone than white men of the same age (J. Natl Cancer, 1986).

Another similar study by another researcher in the same year obtained a similar result, finding that average testosterone levels in black men were 19% higher than in white men, while free testosterone levels were 21% higher (R. Ross, et al 1986).

Causes of racial difference in testosterone levels

Studies indicate that the main factor for this racial difference in hormone concentrations is due to exposure to higher levels of testosterone during pregnancy.

Black women in early pregnancy have 48% higher testosterone levels than white women. Exposure to such high levels of testosterone within the uterus resets the "gonadostat feedback loop" that regulates testosterone secretion to a higher level. This means that for the baby's body, testosterone levels are regulated to higher levels than for white babies (BE Henderson, et al 1988).

Sources:

(Ross, R. et al 1986) Serum Testosterone Levels in Healthy Young
Black and White Men.
https://academic.oup.com/jnci/article-abstract/76/1/45/1006122

(Ellis, L. et all, 1992) Racial/Ethnic Variations in Male
Testosterone Levels.
https://pubmed.ncbi.nlm.nih.gov/1621259/

(Tsai, C. J. et al, 2006) Sex Steroid Hormones in Young Manhood
and the Risk of Subsequent Prostate Cancer: A Longitudinal Study
in African-Americans and Caucasians (United States).
https://pubmed.ncbi.nlm.nih.gov/17111254/


(G. N. Nassar et al, 2022) Testosterone role in male development.
https://www.ncbi.nlm.nih.gov/books/NBK526128/

(BE Henderson, et al 1988) The early in utero oestrogen and testosterone environment of blacks and whites: potential effects on male offspring.
https://www.nature.com/articles/bjc198846