Low Testosterone (Low T) Symptoms, Testing and TRT: What Men Should Know

Dr. Robert Fortino, board-certified in internal medicine · Last updated

The most common symptoms of low testosterone (low T) are low sex drive, fewer morning erections and erectile dysfunction, along with fatigue and low mood. A blood test is the only way to confirm low T. For men on TRT, regular lab work keeps treatment safe and effective.

I’ve been treating men with low testosterone at my Philadelphia and South Jersey offices for nearly 30 years. Here’s what I want every man to know about testing, treatment and why follow-up matters.Maintaining good health is a lifelong commitment, and regular checkups play a crucial role in ensuring that men live their healthiest lives.

Understanding Low T: Low Testosterone Symptoms in Men

Testosterone is a crucial hormone for men, affecting everything from mood to muscle mass, sexual health and bone density. Testosterone levels naturally decline as men age, typically starting around age 30. For some men, the drop is large enough to cause real symptoms, and that’s what we call low testosterone, or low T.

A large New England Journal of Medicine study of more than 3,300 men found that the clearest signs of low T are sexual:

  • Fewer morning erections
  • Low sex drive
  • Erectile dysfunction

The same study found weaker links to:

  • Low energy and fatigue
  • Feeling down or sad
  • Trouble with vigorous physical activity

Men also often tell me about weight gain around the midsection, losing muscle and strength, poor sleep, irritability and trouble concentrating. These can have other causes, from sleep problems to thyroid issues. That’s why I never diagnose low T from symptoms alone.

How Low Testosterone Is Diagnosed

The only way to confirm low testosterone is a blood test, read alongside your symptoms and health history. I trained as an engineer before I became a doctor, and I still approach the body like a system: find out what’s actually going on before you try to fix it.

Every man who comes to me starts with a Low Testosterone Exam & Diagnosis. I do every one of these exams myself. The first visit covers:

  • A full exam and medical history
  • A seca body composition scan, which measures fat and lean muscle
  • Time to ask questions
  • A prescription for your lab work
  • Your follow-up visit to review the results

Lab work is billed separately by the lab, through your insurance when it’s covered, or paid out of pocket. At your follow-up, we go over your results together and decide whether treatment makes sense for you.

I know some men feel uneasy talking about sex drive, erections or mood. You won’t be rushed, and everything you share stays private.

What Testosterone Replacement Therapy Can Do

Testosterone replacement therapy restores testosterone to a healthy range in men whose labs confirm low testosterone. It’s a prescription treatment that requires an in-person evaluation and regular follow-up, and I follow every TRT patient myself.

Results vary, but men on TRT often notice:

  • More energy: less of the afternoon crash and fatigue
  • A stronger sex drive: low testosterone is a common cause of low libido
  • Better mood: many men feel less irritable and more like themselves
  • Help building and keeping muscle: especially paired with strength training
  • Support for bone strength: testosterone helps maintain bone density as you age

TRT isn’t right for every man, and it has risks we’ll talk through before you start. One example: TRT can lower sperm production, so if you’re planning to have children, tell me first.

Why Regular Lab Work Matters on TRT

My patients on TRT have lab work about three times a year, and more often if their results or symptoms call for it. I review every result myself and adjust treatment based on your labs, your symptoms and how you’re feeling. You measure, you adjust, and you keep measuring.

Your lab work checks:

  • Total and free testosterone: to confirm your dose keeps you in a healthy range
  • Hematocrit and hemoglobin: TRT can raise your red blood cell count, which thickens the blood and can increase the risk of clots
  • PSA (prostate-specific antigen): to keep an eye on prostate health
  • Estradiol: to see whether too much testosterone is converting to estrogen
  • Cholesterol and blood sugar: to track your heart and metabolic health

Numbers on a lab report don’t tell the whole story. At your checkups, we also take your blood pressure, review your seca body composition scan and talk about your energy, strength and sleep. As an osteopathic physician, I was trained to treat the whole person, not just a lab value.

Can You Do TRT and Medical Weight Loss Together?

Yes, when it’s medically appropriate, and for many men it’s a smart combination. When you lose weight on GLP-1 medications like semaglutide or tirzepatide, you can lose muscle along with fat. For men with confirmed low testosterone, TRT can help protect that muscle while you lose fat.

I’ve been strength training for 40 years, and I see the same thing in my office every week: most men starting weight loss have less muscle than they should. That’s the idea behind our Strong, Not Skinny approach. The goal is losing fat while keeping your strength, energy and the ability to stay active for years.

TRT Myths vs. Facts

Myth: TRT is only for older men. Fact: Men in their 30s and 40s can have low testosterone too. Your symptoms and lab results matter more than your age.

Myth: TRT is just for building muscle. Fact: TRT can help with muscle, but men usually come to me for low energy, low sex drive or feeling off. The goal is restoring a healthy level, not pushing past it.

Myth: Testosterone therapy causes “roid rage.” Fact: Aggression is linked to steroid abuse at very high doses, not to doctor-supervised TRT that keeps levels in a healthy range.

Myth: Once you start TRT, you can never stop. Fact: TRT is usually a long-term treatment, but it’s always your decision. If you want to stop, we’ll make a plan together and keep monitoring you.

Low T Testing and Testosterone Replacement Therapy Near You

If you’re searching for testosterone replacement therapy near you, I see men for low T testing, TRT and men’s health care at two offices:

Both offices are quiet and private, and you’ll work directly with me and my clinical team.

Frequently Asked Questions

What is TRT? TRT, or testosterone replacement therapy, is a prescription treatment that brings testosterone back to a healthy range in men whose lab work confirms low T. It requires a medical evaluation and regular lab monitoring.

What are the side effects of TRT? Possible side effects include acne, fluid retention, a higher red blood cell count, breast tenderness, lower sperm production and smaller testicles. TRT can also worsen sleep apnea. Regular lab work and checkups help me catch these early and adjust your treatment.

How are testosterone levels tested? With a simple blood test, usually drawn in the morning, when testosterone levels are highest. Because levels vary, a low result is often confirmed with a second test before diagnosing low T.

What causes low testosterone? Aging is the most common cause. Low T is also linked to obesity, type 2 diabetes, sleep apnea, certain medications such as opioids and steroids, and problems with the testicles or pituitary gland.

How often should you get blood work on TRT? Most men on testosterone replacement therapy need blood work several times a year. My patients have lab work about three times a year, and more often if their results or symptoms call for it.

What are the first signs of low testosterone? The signs most closely linked to low testosterone are fewer morning erections, low sex drive and erectile dysfunction. Low energy, fatigue and a low mood can also be signs.

How much does a low testosterone exam cost? My Low Testosterone Exam & Diagnosis covers the exam, your medical history, a seca body composition scan, a lab work prescription and your follow-up visit. Lab work is billed separately.

Can TRT be done through telehealth? No. TRT requires an in-person exam and in-person follow-up visits at my Philadelphia or South Jersey office.

Does TRT affect fertility? It can. TRT can lower sperm production, so tell me if you’re planning to have children before starting treatment.

Where can I find a low T doctor near me in South Philly or South Jersey? I see men at my South Broad Street office in South Philadelphia and my office in Turnersville, NJ, serving Washington Township and Gloucester County. Contact either office to schedule your Low Testosterone Exam & Diagnosis.