What Is Testosterone Replacement Therapy (TRT)?
Testosterone replacement therapy (TRT) is a prescription treatment that uses manufactured testosterone to raise low testosterone levels in men with hypogonadism, a condition in which the body doesn't make enough of the hormone. The FDA approves testosterone products for men who have low testosterone along with an associated medical condition.
Hypogonadism is common. The Endocrine Society estimates that it affects about 35% of men older than 45, and 30% to 50% of men with obesity or type 2 diabetes.
Testosterone Replacement Therapy (TRT) at a Glance
| Also called | Testosterone therapy |
|---|---|
| What it treats | Low testosterone with symptoms (male hypogonadism) |
| How it works | Replaces the testosterone the body normally makes |
| How it's given | Skin gel, patch, injection, implanted pellets, gum tablet, nasal gel or oral capsule |
| How long it lasts | Only while you take it. Levels return to baseline after stopping. |
| Side effects | Acne, ankle swelling, breast tenderness, higher red blood cell count, lower sperm count, higher blood pressure |
| FDA status | Approved for men with low testosterone and an associated medical condition. A controlled substance. |
How Does TRT Work?
TRT works by replacing the testosterone your testicles normally make. Testosterone helps maintain sex drive, muscle, sperm production and bone health. Outside testosterone suppresses the brain's signals to the testicles, so they make less of their own testosterone and sperm. TRT must continue to keep levels normal.
Who Is TRT For?
TRT is for men who have symptoms of low testosterone and blood tests that confirm consistently low levels. Qualifying conditions include testicles that fail because of genetic problems or chemotherapy, and problems with the hypothalamus or pituitary gland.
- Symptoms: lower sex drive, erectile dysfunction, reduced energy and muscle mass, breast enlargement, depressed mood or hot flashes (when levels are very low)
- Blood tests: at least two early-morning (7 to 10 a.m.) tests showing low testosterone. Normal levels are about 300 to 1,000 ng/dL, depending on age and the lab.
Reversible causes, such as obesity, should be addressed first. Testosterone is not FDA-approved to improve strength, athletic performance or appearance. In June 2026, the FDA asked manufacturers to remove a label statement saying TRT's safety and effectiveness in age-related low testosterone had not been established.
What to Expect Before, During and After TRT
TRT involves confirming the diagnosis, choosing a form of testosterone and having regular follow-up blood tests.
Before Treatment
Your provider takes a history, does a physical exam and may order hematocrit, liver function, luteinizing hormone, prolactin and PSA (prostate-specific antigen) tests.
Forms of TRT
- Gel: applied daily. It can transfer to others through skin contact while wet.
- Injections: into a muscle every one to two weeks, under the skin weekly, or a long-acting form every 10 weeks in a medical office
- Patches: applied daily, rotating sites
- Pellets: implanted under the skin every three to six months
- Other forms: gum tablets, nasal gel or oral pills, used two or three times a day
After Starting
Providers typically check your testosterone about 30 days after you start. The Endocrine Society recommends monitoring symptoms, side effects, testosterone, hematocrit and prostate cancer risk during the first year. The usual target is the mid-normal range, typically 450 to 600 ng/dL.
TRT Results: What It Can and Can't Do
TRT's clearest proven benefit in older men with low testosterone is better sexual function. In the Testosterone Trials, a year of testosterone gel in 790 men 65 or older with symptoms and testosterone under 275 ng/dL increased sexual activity, desire and erectile function. Mood improved slightly, but vitality and walking distance did not.
If symptoms don't improve after three to six months, your provider may recommend stopping, because low testosterone may not be their cause.
TRT Risks and Side Effects
TRT's side effects include acne, mild fluid retention, breast enlargement or tenderness, urinary symptoms, worsening sleep apnea, smaller testicles and lower sperm count. It can raise PSA and red blood cell count, which thickens the blood. In 2025, the FDA confirmed that all testosterone products raise blood pressure.
- Heart: in the TRAVERSE trial of 5,246 men aged 45 to 80 with or at high risk of heart disease, testosterone gel didn't increase major cardiac events compared with placebo. Atrial fibrillation, acute kidney injury and pulmonary embolism were more common. In 2025, the FDA called for removing Boxed Warning language about increased cardiovascular risk.
- Prostate: the FDA says data have not generally shown higher prostate cancer risk with TRT. Uncertainty remains because prostate cancer can take years to develop, so screening and monitoring continue.
Call your provider about leg swelling or pain, breathing trouble during sleep, trouble urinating or erections that last too long.
Who Shouldn't Have TRT?
TRT isn't recommended for men planning to have children or with conditions testosterone can worsen:
- Known or suspected prostate or breast cancer
- An enlarged prostate that makes urination difficult, or an elevated PSA
- A high red blood cell count or blood clots
- Untreated sleep apnea or untreated heart failure
- A heart attack or stroke within the past six months
In June 2026, the FDA requested label changes under which TRT would be off-limits only for men with prostate cancer that has spread. Your provider still assesses prostate risk before and during treatment.
Women who can become pregnant should not use testosterone.
TRT vs. Clomiphene and Lifestyle Changes
TRT replaces testosterone directly, while clomiphene and lifestyle changes help the body make more of its own.
| How it helps | FDA status for low testosterone | Best suited for | |
|---|---|---|---|
| TRT | Replaces testosterone. Lowers sperm count. | Approved with an associated medical condition | Confirmed hypogonadism |
| Clomiphene citrate | Aims to keep the body's own production going | Not approved for this use | Men who want to preserve fertility |
| Weight loss, exercise, medicine changes | Treats reversible causes, such as obesity or certain medicines | Not a drug | Recommended as part of managing low testosterone |
TRT at GENEVA
At GENEVA Primary Care & Med Spa in Alpharetta, GA, a provider evaluates symptoms of low testosterone and orders the needed blood tests. Based on that evaluation, your provider recommends treatment at GENEVA or a referral to a specialist.
Learn more about hormone replacement therapy for men and men's health care. GENEVA serves patients from Alpharetta, Johns Creek, Milton, Roswell and Cumming.
Related Terms
Testosterone Replacement Therapy (TRT) FAQs
Is testosterone replacement therapy safe?
Testosterone replacement therapy is generally safe for men with confirmed hypogonadism who are screened and then monitored. In the TRAVERSE trial of 5,246 men with or at high risk of heart disease, major cardiac events occurred in 7.0% of men on testosterone gel and 7.3% on placebo. Atrial fibrillation, acute kidney injury and pulmonary embolism were more common with testosterone, which also raises blood pressure. TRT isn't right for men with untreated heart failure, untreated sleep apnea or a recent heart attack or stroke.
What testosterone level qualifies for TRT?
Testosterone replacement therapy is considered when at least two early-morning blood tests show low testosterone and you also have symptoms. The American Urological Association treats 300 ng/dL as a reasonable threshold, and the Endocrine Society gives 264 ng/dL as the lower limit of normal for healthy, nonobese men. Levels can drop temporarily with severe illness, too much exercise, poor nutrition or certain medicines, so a single low result isn't enough for a diagnosis.
How long does it take for TRT to work?
Testosterone replacement therapy can take a few weeks to produce noticeable changes, and timing varies from person to person. Providers typically check your testosterone level about 30 days after you start. Sexual function tends to respond most clearly: in the Testosterone Trials, a year of testosterone gel increased sexual activity, desire and erectile function in men 65 and older. If symptoms haven't improved after three to six months, your provider may recommend stopping TRT.
Do you have to stay on TRT forever?
No, you can stop testosterone replacement therapy, but its benefits last only while you take it. TRT doesn't cure the cause of low testosterone, and it makes the testicles produce less of their own. After you stop, your level returns to baseline, and your body takes time to restart its own production. Men stop TRT because of side effects, lack of benefit or a new health condition that makes it unsafe. Talk with your provider before stopping.
Does TRT cause infertility?
Yes, testosterone replacement therapy can lower sperm count and cause infertility, so it isn't recommended for men planning to have children. Cleveland Clinic notes that restoring fertility after TRT can be very expensive and take a long time. Men who want to preserve fertility may be offered other options, such as clomiphene citrate (not FDA-approved for this use) or gonadotropin therapy such as hCG. Raise fertility plans before starting any testosterone treatment.
Can a primary care provider prescribe TRT?
Yes, a primary care provider can evaluate low testosterone and prescribe TRT when it's appropriate. In the United States, primary care physicians write about 60% of testosterone prescriptions, according to a 2022 review. Diagnosis rests on symptoms, a physical exam and two morning blood tests. At GENEVA in Alpharetta, a provider evaluates your symptoms and lab results, then recommends treatment at GENEVA or a referral to a specialist. A specialist referral may be needed before starting TRT if you have an elevated PSA or a nodule found on a prostate exam.