Is Bioidentical Testosterone Safer?

Some companies throw around the term “bioidentical” to make their testosterone replacement therapy (TRT) sound safer, more natural, or more customized. But here’s the reality: Almost all FDA-approved TRT is already bioidentical—the testosterone molecule is identical to what your body makes.

“Bioidentical is just a catchphrase for ‘natural,’” says endocrinologist Steven Wise, M.D. “It makes it sound like it’s better or somehow less dangerous. I’ve even seen advertisements that say, ‘unlike synthetic steroids, bioidentical steroids do not cause side effects’ … that is absolutely untrue.”

What really matters is how testosterone therapy is delivered, dosed, and monitored—not whether the box uses a buzzy label like “bioidentical hormone replacement therapy for men.”

If you’re one of the many men over 45 dealing with low testosterone—and hoping to improve libido, mood, muscle strength, or overall vitality—understanding what actually makes TRT bioidentical (and when the label does or doesn’t matter) can help cut through the noise.¹

Meet Our Experts

• Justin Houman, M.D., FACS is a urologist with Tower Urology at Cedars-Sinai Medical Center.
• Steven Wise, M.D., is a board-certified endocrinologist.

What is BHRT for Men?

BHRT stands for bioidentical hormone replacement therapy—hormones that are chemically identical to the ones your body makes. For men, BHRT typically refers to bioidentical testosterone replacement therapy (TRT), which is the same testosterone molecule (C19H28O2) your body naturally produces. Whether you inject it, apply it, or take it orally, the chemical structure is the same.

TRT is typically made from plant sterols—compounds that resemble cholesterol, the building block your body uses to make testosterone. Chemists tweak the sterols in a lab until they match the hormone your body already produces.

Here’s the important part: Nearly all FDA-approved testosterone medications are already bioidentical.

And regardless of where the raw ingredients originate, all testosterone replacement therapy is synthesized in a lab. In fact, some treatments marketed as bioidentical, like scrotal creams, oral testosterone, and some pellets, may actually behave less like natural testosterone once they’re in the body.

Bioidentical TRT

Bioidentical TRT simply means testosterone therapy that uses hormones identical to the testosterone your body produces. And again, that’s what almost all FDA-approved testosterone replacement therapy already is. ²

“Nearly all prescription testosterone therapies, like testosterone cypionate, enanthate, or transdermal gels, are already bioidentical, even if they don’t use that label,” says urologist Justin Houman, M.D. “Biologically, testosterone is testosterone.”

Bioidentical TRT is prescribed for men with hypogonadism, or low testosterone, which is marked by symptoms like low libido, fatigue, changes in mood, or reduced muscle mass.

FDA-approved bioidentical TRT comes in a few forms, including:

• Injections
• Creams or gels
• Troches (dissolving lozenges)
• Pellets placed under the skin

The outliers? Older synthetic forms of testosterone, like fluoxymesterone and methyltestosterone. These are rarely prescribed today because they can cause liver toxicity. ³

Do injections count as bioidentical?

Some argue that injectable testosterone isn’t bioidentical because it contains a small chemical add-on called an ester, which helps the hormone dissolve in oil and release steadily. But once it’s in your bloodstream, your body removes the ester, leaving testosterone identical to your own.

Where delivery makes a difference

Even though the testosterone molecule in cream and oral forms of TRT is identical to what your body makes, how it gets into your system can change how much they raise testosterone levels, how steady they stay, and how much they convert into other androgens.

Testosterone creams

These are still bioidentical, but the skin on the scrotum—the most common application site—contains above-average levels of an enzyme called 5-alpha reductase.⁴ The enzyme converts testosterone into a more potent form called dihydrotestosterone (DHT) at a higher-than-normal rate.
At high levels, DHT can shift your hormone balance in a way that doesn’t match how your body normally produces testosterone.

Oral testosterone (pills or under-the-tongue troches)

These forms are also bioidentical, but they can create less steady blood levels compared to injections, Wise says. Doctors typically prescribe these to men who are needle-averse, or who need very small dose adjustments, or require a fast on/off option for symptom control.

Compounded BHRT

Compounded testosterone is custom-mixed by a compounding pharmacy. It can come in any format—troches, creams, injections, or pellets. The catch: While the raw ingredients may be FDA-approved, the final product is not, which means potency and sterility can vary more than with standardized prescription versions. ⁵

However, compounded BHRT isn’t unsafe.

Compounding pharmacies still have to meet quality standards. “FDA-approved testosterone cypionate or gels are tightly regulated and consistent,” Houman says. “In most cases, I prefer those approved versions for reliability and safety.”

Risks & Benefits of BHRT

Because almost all modern testosterone therapies are already bioidentical, the benefits of BHRT are simply the benefits of TRT done correctly. ⁶ For men with documented testosterone deficiency, TRT can:

• Improve libido
• Lift mood
• Boost energy
• Support weight loss
• Increase lean muscle
• Help maintain or improve bone density.

Some benefits show up within a few weeks; others build steadily over several months.

In the past, it was believed that TRT put men at greater risk for cardiovascular events, but recent research is changing this view. In the large 2023 TRAVERSE trial, men with low testosterone and existing cardiovascular risk did not experience higher rates of heart attack, stroke, or other major cardiac events while on TRT. ⁷ Based on these findings, the FDA recommended removing the cardiac warning label from TRT products.

Common side effects of TRT include:

• Acne or oily skin
• Worsening sleep apnea
• Reduced sperm count and infertility
• Gynecomastia
• Mood changes
• Elevated hematocrit (a rise in red blood cells)

None of these depend on whether the testosterone is labeled “bioidentical.”

“Effectiveness and side effects, like acne, mood changes, fluid retention, or altered fertility, depend more on dosage, delivery route, and monitoring, not the molecule itself—not the marketing term attached to the vial,” Houman says.

Off-label uses of BHRT

Some clinics mix testosterone with other hormones, then market the blend as “bioidentical” or “customized.” This is often the case with some heavily marketed testosterone pellets, which are touted as a more “natural” or “clean” option.

Problem is, these hormone mixes aren’t always safe. “Some are legitimate and evidence-based, while others, especially compounded ‘custom hormone blends,’ are largely marketing-driven,” Houman says. “These can be risky because of inconsistent dosing and lack of oversight. In men’s health, [pure] testosterone is the only ‘bioidentical’ hormone therapy with robust clinical data supporting its use.”

How to Find a Qualified Provider

If you’re TRT-curious, look for a board-certified urologist, endocrinologist, or internal medicine physician with experience in hormone replacement therapy. Some clinicians pursue BHRT-specific training, which can be helpful—as long as their approach stays rooted in evidence, not branding.

A qualified provider should:

• Order the appropriate bloodwork (including two morning testosterone tests)
• Explain risks, benefits, and delivery options clearly
• Avoid pushing proprietary compounded blends
• Schedule ongoing follow-ups for labs and symptom monitoring

If you’re searching for bioidentical hormone therapy for men or BHRT for men, the most important thing is finding a clinician who understands hormonal health—not just a clinic with good marketing.

Mentioned in This Article:

Testosterone

Testosterone provides the foundation for Hone’s testosterone replacement therapy plans, used to treat low testosterone levels and boost energy, strength, and libido. Available via injections, cream and dissolvable troches.

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About the reviewer

Joshua Calvert, M.D., is a urologist who specializes in vasectomy and vasectomy reversal, Peyronie’s disease, testosterone management, and male infertility.