Guides

Hormone genetics, explained honestly

What research has found about the genes involved in testosterone and anabolic steroids, how strong that evidence is, and the blood tests that show how your body is coping. Every claim is sourced.

• Androgen receptor CAG repeats

  The AR gene's CAG repeat: what it is, what studies link it to, and how it is tested in the UK.

• UGT2B17 deletion

  A common gene deletion that changes how testosterone leaves the body in urine, and why anti-doping cares.

• CYP19A1 and aromatase

  How the aromatase gene turns testosterone into oestradiol, and what large studies found about its variants.

• Genetics of steroid response

  Which genes have been studied in connection with testosterone and anabolic steroids, and how strong the evidence is.

• Can a DNA test show steroids are safe?

  The honest answer, and what genetic tests and blood tests can each tell you.

• Blood tests for steroid users

  What to test, when, and where in the UK, from published guidance for people who use anabolic steroids.

• Best DNA tests for hormones UK

  The UK's at-home DNA tests that cover hormones and fitness, compared on price, genes and privacy.