What the value means
Estradiol (E2) is reported in pmol/L. In men it is produced mainly in fat tissue by the enzyme aromatase, which converts testosterone into estradiol. Reference ranges vary considerably between laboratories, and standard immunoassays are less accurate at the low concentrations typical for men; mass spectrometry (LC-MS/MS) is more reliable. A value “within range”, or slightly above it, does not by itself say whether things are optimal – the ratio to testosterone and your symptoms matter.
Possible causes
- Excess weight and visceral fat – more fat tissue means more aromatase, and therefore more estradiol alongside lower testosterone.
- Alcohol and the liver – regular drinking and liver disease slow the breakdown of estrogens.
- High testosterone – especially with testosterone therapy or anabolic steroid use, estradiol rises as well.
- Medicines and supplements – some medicines (for example spironolactone) affect hormonal balance; high-dose biotin can falsely raise an immunoassay result.
- Rare causes – an overactive thyroid or tumours of the testes or adrenal glands should be ruled out by a doctor when values are clearly high.
What you can do
- Confirm the result – repeat the test in the morning while fasting, ideally with a sensitive method, and avoid biotin-containing supplements for a few days beforehand.
- Add context – total and free testosterone, SHBG, LH, prolactin, liver tests and TSH.
- Body weight – in men with excess weight, reducing body fat usually improves the testosterone-to-estradiol balance.
- Less alcohol – cutting back on alcohol eases the load on the liver and supports hormonal balance.
- No “blockers” on your own – estradiol that is too low harms bones, libido and mood; supplements promising to “lower estrogen” have weak evidence.
When to see a doctor
See a doctor (an endocrinologist or urologist) if your breast tissue is growing or tender, if libido or erections decline, if you have fertility problems, or if estradiol is clearly raised on repeat testing. If you take testosterone or other hormones, discuss the result with the doctor managing your treatment and do not stop any medication on your own.