Why Men Need Estrogen Too: Testosterone, Estradiol, and Bone Health

Most people think of testosterone as a male hormone and estrogen as a female hormone. Human biology is not quite that tidy.

Men naturally produce estradiol, an important form of estrogen. Much of it is created when the aromatase enzyme converts a portion of testosterone into estradiol.

This conversion is not a mistake or an unwanted side effect. Estradiol contributes to bone maintenance, sexual function, body composition, and other aspects of men’s health.

That is why lowering estradiol simply because a man is receiving testosterone—or because a laboratory result is outside a preferred range—may not always be the right decision.

Men Make Estrogen for a Reason

Aromatase is present in multiple tissues, including fat, the brain, testes, and bone. It converts some testosterone into estradiol.

Men generally have much lower estradiol levels than premenopausal women, but “lower” does not mean unimportant. Men need an appropriate balance of testosterone and estradiol.

The goal of hormone optimization should not be to eliminate estrogen. It should be to understand the complete hormone picture, evaluate symptoms, and avoid unnecessarily suppressing a hormone the body uses.

How Do Men Develop Osteoporosis?

Osteoporosis is often viewed as a women’s health issue, but men can also experience significant bone loss and fractures.

Possible contributors include:

• Aging

• Low testosterone or hypogonadism

• Low bioavailable estradiol

• Smoking

• Heavy alcohol use

• Low vitamin D or calcium intake

• Inadequate resistance or weight-bearing exercise

• Low muscle mass

• Long-term corticosteroid use

• Thyroid or parathyroid disorders

• Malabsorption or gastrointestinal disease

• Certain medications

• Androgen-deprivation therapy for prostate cancer

Bone is constantly being broken down and rebuilt. Hormones help regulate this remodeling process. When available sex-hormone levels become too low, bone breakdown may begin to outpace bone formation.

Estradiol Plays an Important Role in Men’s Bones

Research has repeatedly associated lower estradiol levels in older men with poorer bone health.

The prospective STRAMBO study followed hundreds of men aged 60 and older for up to eight years. Lower bioavailable estradiol was associated with faster deterioration in several measures of cortical bone at the tibia. Men with both low bioavailable estradiol and low free testosterone experienced greater deterioration in multiple measures of bone microarchitecture.

The findings do not prove that every man with low estradiol needs estradiol medication. They demonstrate that estrogen availability is part of male bone physiology and should not automatically be treated as a problem.

Testosterone matters too. It supports muscle mass and strength, which can influence balance, physical function, and the forces placed on bone. Testosterone also provides the source material from which men make much of their estradiol.

Healthy male bone physiology involves both hormones.

Why SHBG and Free-Hormone Availability Matter

A total testosterone or total estradiol result does not always tell the entire story.

Sex hormone-binding globulin, or SHBG, attaches to sex hormones in the bloodstream. When SHBG changes, the proportion of hormone that is free or bioavailable can change as well.

SHBG commonly increases with age. A man may therefore have a total testosterone result that appears acceptable while the amount available to tissues is lower.

This is one reason hormone care should not be based on a single number. Total testosterone, free testosterone, estradiol, SHBG, symptoms, medical history, body composition, and treatment response may all provide useful context.

Think of a blood draw as a Polaroid. It shows what was happening at that moment, but it does not automatically explain the entire story.

Should Estradiol Be Blocked During Testosterone Therapy?

Aromatase inhibitors, such as anastrozole, reduce the conversion of testosterone into estradiol. These medications have appropriate clinical uses, but routine estrogen suppression is not automatically necessary for every man receiving testosterone therapy.

Some men may experience breast tenderness, gynecomastia, fluid retention, or other concerns that prompt further evaluation. These symptoms should not automatically be blamed on estradiol without looking at the full clinical picture.

The questions should include:

• Is the symptom actually related to estradiol?

• Was the laboratory test timed appropriately?

• Is the testosterone dose or dosing schedule contributing?

• Is the estradiol result being interpreted with an appropriate assay?

• What are the man’s symptoms?

• Are there other medical explanations?

• Could suppressing estradiol create new problems?

Research has shown that aromatase inhibition can reduce bone mineral density in older men. This makes long-term, unnecessary estrogen suppression particularly concerning in someone who already has osteoporosis risk factors.

An estradiol result should be interpreted—not feared.

What About High Estradiol in Men?

The fact that men need estradiol does not mean every estradiol level is ideal or that symptoms should be ignored.

Higher body-fat levels may increase aromatase activity. Alcohol use, liver health, medications, testosterone dosing, and other health factors can also influence hormone levels.

The appropriate response depends on the cause, the degree of elevation, the symptoms, and the rest of the hormone profile. Sometimes the better solution is adjusting testosterone dosing or addressing a contributing health factor—not reflexively adding another medication.

More treatment is not always better treatment.

Bone Health Requires More Than Hormone Therapy

Testosterone therapy is not a stand-alone osteoporosis treatment for every man. Men with osteoporosis or significant fracture risk may require additional evaluation and medications specifically approved to reduce fractures.

A complete bone-health plan may include:

• Bone-density testing when indicated

• Evaluation for secondary causes of osteoporosis

• Adequate protein intake

• Appropriate calcium and vitamin D

• Resistance and weight-bearing exercise

• Maintaining muscle mass

• Reducing tobacco and excessive alcohol use

• Fall-risk reduction

• Treatment specifically directed at osteoporosis when appropriate

Hormone optimization may be one part of the plan when a man has clinically confirmed hypogonadism, but it should not replace comprehensive bone evaluation.

Male Hormone Care Should Look Beyond Testosterone

Good testosterone care is not simply about raising one laboratory value.

It requires understanding how testosterone, estradiol, SHBG, symptoms, muscle health, metabolic health, medications, and lifestyle factors interact.

At AdoreU, we review the full picture. Every visit is a conversation about how you feel, what your laboratory trends show, how you are responding, and what needs to happen next.

If you are experiencing low energy, decreased strength, reduced libido, changes in body composition, or concerns about low testosterone, schedule an appointment with AdoreU in O’Fallon, Missouri. We will evaluate whether hormone optimization is appropriate and develop a plan based on your health—not a generic testosterone number.

Call or text 636-486-6770 to schedule a Comprehensive Assessment.

References

Piot A, Chapurlat RD, Claustrat B, Szulc P. Relationship between sex steroids and deterioration of bone microarchitecture in older men: The prospective STRAMBO study. Journal of Bone and Mineral Research. 2019;34(9):1562-1573. doi:10.1002/jbmr.3746.

Burnett-Bowie SA, McKay EA, Lee H, Leder BZ. Effects of aromatase inhibition on bone mineral density and bone turnover in older men with low testosterone levels. Journal of Clinical Endocrinology & Metabolism. 2009;94(12):4785-4792. doi:10.1210/jc.2009-0739.

Finkelstein JS, et al. Gonadal steroids and body composition, strength, and sexual function in men. New England Journal of Medicine. 2013;369:1011-1022. doi:10.1056/NEJMoa1206168.

Endocrine Society. Testosterone Therapy in Men With Hypogonadism: An Endocrine Society Clinical Practice Guideline. Journal of Clinical Endocrinology & Metabolism. 2018;103(5):1715-1744.

This article is for educational purposes and does not replace personalized medical care. Hormone therapy and aromatase inhibitors have potential benefits and risks and should be used only after an individualized medical evaluation.