Estradiol (E2) Test: What It Means on Testosterone
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[Glossary · How doses act in the body]

Estradiol (E2)

Also called E2, estradiol test, oestradiol · Reviewed

Definition: Estradiol, or E2, is the main type of estrogen in women of childbearing age. Men make small amounts too. An estradiol test measures it in a blood sample. MedlinePlus lists three estrogens that are commonly tested: estrone (E1), estradiol (E2) and estriol (E3).

Why it shows up on labs when you track doses

Testosterone turns into estradiol in the body. The Xyosted label names estradiol and DHT as the major active metabolites of testosterone. That is why estradiol is often ordered alongside testosterone.

MedlinePlus says estradiol or estrone tests may be used in men to see whether too much estrogen is behind breast growth (gynecomastia), infertility, erectile dysfunction or late puberty.

The anastrozole label says this aromatase inhibitor significantly lowers serum estradiol. Its approved uses are breast cancer treatments in postmenopausal women. The same label warns that total cholesterol may rise and bone density may fall.

Common mix-ups

  • Estradiol is not all estrogen. Estrone (E1) and estriol (E3) are separate tests. Check which one your report shows.
  • Levels vary more in women. MedlinePlus says estrogen in men changes little through life, while in women it shifts with the cycle, pregnancy and menopause, so repeat tests may be needed to see a trend.
  • Medicines matter. MedlinePlus says birth control pills and hormone therapy can affect results. Tell your provider what you take.

Each lab sets its own reference range, so read your result against the range printed on your own report, and talk with your clinician about what it means for you.

Read more on Dose Track: Estrogen on TRT · Anastrozole guide · Logging lab results in Dose Track

General education drawn from labels and published studies, not personal medical advice. Your prescriber, pharmacist and the label that came with your product are the final word.
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Frequently asked questions

Why does testosterone raise estradiol?+
The body converts some testosterone into estradiol. The Xyosted label lists estradiol as one of the two major active metabolites of testosterone.
What estradiol level is normal for a man?+
Labs set their own reference ranges, and the right range depends on age, sex and which test was run. Your clinician reads the result against the range on your report.

Sources

  1. MedlinePlus (NIH): Estrogen Levels Test
  2. Xyosted (testosterone enanthate) US prescribing information, sections 1, 5 and 12.3, DailyMed
  3. Anastrozole tablets US prescribing information (Breckenridge), sections 5 and 12, DailyMed

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