Before Testosterone Replacement Therapy, Look Under the Hood.

Why low testosterone is often a symptom—not the whole story.

Before TRT, look under the hood.

Created by Chris Caffrey, ACNP, PMHNP, Functional Medicine-trained

July 12th 2026

Most men don't wake up one morning and suddenly stop feeling like themselves. The change is usually gradual. Workouts that once left you energized now leave you sore for days. The weight around your waist becomes harder to lose despite eating much the same way you always have. Your motivation fades, your energy isn't what it used to be, and your patience grows shorter. You begin wondering whether this is simply what getting older feels like—or whether something else is going on.

Eventually, someone mentions testosterone.

A quick internet search seems to explain everything. Social media is filled with dramatic before-and-after transformations, and online clinics promise renewed energy, better workouts, sharper thinking, and a younger version of yourself—all from a single prescription. It's an appealing story because simple explanations are comforting. We naturally want one problem to have one solution. Unfortunately, the human body has never been particularly interested in simple stories.

Imagine you're driving home from work when your check engine light suddenly appears. That little amber symbol doesn't tell you what's wrong. It doesn't say whether the problem is a loose gas cap, a failing sensor, or an engine that's about to quit. It simply tells you that something deserves your attention. Covering the light with black tape doesn't fix the problem—it only hides the message.

Low testosterone often works the same way.

Sometimes testosterone itself is the problem. More often, it's the messenger pointing toward something deeper: poor sleep, untreated sleep apnea, excess visceral fat, insulin resistance, chronic stress, medication effects, nutritional deficiencies, or another underlying condition that's been quietly developing for years. The goal isn't simply to raise a laboratory number. It's to understand why that number changed in the first place.

That distinction may seem subtle, but it changes everything about how we approach treatment.

Looking Beyond the Number

Testosterone has become one of the most discussed hormones in modern medicine, and for good reason. It influences muscle mass, bone density, libido, mood, recovery, red blood cell production, and many of the functions that help us feel healthy and capable. When men truly have testosterone deficiency, appropriate treatment can be life-changing. The problem isn't that testosterone matters. The problem is that the conversation has become far too simplistic.

Low energy? TRT.

Weight gain? TRT.

Brain fog? TRT.

Low motivation? TRT.

The reality is rarely that straightforward.

Fatigue alone has dozens of possible causes. Depression, thyroid disease, poor sleep, sleep apnea, obesity, diabetes, chronic stress, nutritional deficiencies, medications, and testosterone deficiency can all produce remarkably similar symptoms. A low testosterone level may explain those symptoms—or it may simply be another clue pointing toward a larger story.

That's where thoughtful medicine separates itself from algorithmic medicine.

Good medicine doesn't stop when it finds one abnormal laboratory result. It asks why that result became abnormal in the first place. As Dr. Mark Hyman has often emphasized, symptoms are rarely the disease itself; they're clues pointing toward an underlying imbalance. Whether we're talking about digestive disorders, autoimmune disease, depression, or hormone deficiency, the principle remains remarkably consistent. Treating symptoms certainly has value, but understanding why they developed often creates opportunities that medication alone never could.

That philosophy has shaped the way I approach hormone optimization. In my experience, people rarely seek care because they want a higher testosterone level. They come because they want their life back. They want enough energy to finish a workout without feeling exhausted for the rest of the day. They want to think clearly during an important meeting, reconnect with their spouse, keep up with their children, and recognize the version of themselves they remember being. Testosterone may ultimately become part of that solution, but it shouldn't be the first conclusion we reach.

Opening the Hood

Once we move beyond the laboratory number, the conversation becomes much more interesting.

The question is no longer whether testosterone matters—we already know it does. The more important question is why so many men walk into a clinic convinced they need testosterone when something entirely different may be driving the problem.

Every week, I hear some version of the same story.

"I'm exhausted."

"I can't build muscle like I used to."

"I've gained weight even though I'm eating the same way."

"My motivation is gone."

"I just don't feel like myself anymore."

Those concerns are real, and they deserve to be taken seriously. They're also among the most common—and least specific—symptoms in medicine. Fatigue can certainly result from low testosterone, but it can just as easily reflect untreated sleep apnea, depression, chronic stress, insulin resistance, thyroid disease, nutritional deficiencies, medication effects, or simply years of sacrificing sleep while balancing work, family, and life's responsibilities. Symptoms rarely tell us exactly what the problem is. They simply tell us there's a problem worth investigating.

One of the first questions I ask during an initial consultation has nothing to do with testosterone. I simply ask, "When was the last time you truly felt like yourself?" That question often changes the entire conversation.

Sometimes the answer is, "Before COVID." Sometimes it's, "Before my second child was born." Sometimes it's, "Before work became so stressful." Occasionally someone pauses for several seconds before quietly saying, "Honestly... I can't remember."

That answer often reveals more than a laboratory value ever could. Testosterone rarely disappears overnight. More often, men slowly drift away from feeling well. They adapt to being tired, normalize poor sleep, accept gaining twenty pounds, and convince themselves that declining motivation is simply part of getting older. By the time they finally seek help, low testosterone feels like the obvious explanation because it's the first explanation that finally has a name.

Sometimes they're right. Just as often, they're only seeing one chapter of a much longer story.

That's why I resist the temptation to stop investigating the moment I find one abnormal laboratory result. Medicine naturally rewards certainty, but biology rarely offers it. A low testosterone level may explain the symptoms, or it may simply be one consequence of something that's been quietly developing beneath the surface.

My evaluation begins long before we discuss treatment. If the first question is, "Which form of testosterone do you want?" we've skipped the most important part of the conversation. Before deciding whether testosterone belongs in the treatment plan, I want to understand the person sitting across from me.

That starts with your story.

We'll certainly discuss your symptoms, but we'll also talk about your sleep, nutrition, stress, exercise habits, medications, work, previous laboratory testing, and long-term goals. A forty-five-year-old father hoping to keep up with his teenage son on weekend hikes deserves a different conversation than a younger man whose primary concern is preserving fertility while treating symptomatic hypogonadism. Those differences matter because your goals are every bit as important as your laboratory values.

Only then do laboratory studies become truly meaningful. One of the biggest misconceptions about testosterone testing is that it's a single blood test with a simple answer. In reality, hormones exist within an interconnected network. Total testosterone is important, but it rarely tells the whole story. Depending on the situation, free testosterone, sex hormone-binding globulin (SHBG), luteinizing hormone (LH), follicle-stimulating hormone (FSH), estradiol, thyroid function, blood counts, metabolic markers, and prostate health may all contribute to understanding what's actually happening.

The goal isn't to order every laboratory test available. The goal is to ask better questions so the right tests provide meaningful answers.

The Body Is Remarkably Logical

One of the greatest misconceptions about hormones is that they behave independently.

They don't.

Every hormone in your body is part of an extraordinarily complex communication network. Your brain, pituitary gland, thyroid, adrenal glands, body fat, muscles, liver, and reproductive organs are constantly exchanging information, adapting to your environment, and trying to keep you healthy. Testosterone is one voice in that conversation—not the entire conversation.

That's why I rarely think about testosterone in isolation. I think about the environment your body is responding to.

If you're sleeping five hours a night, living under chronic stress, carrying excess visceral fat, eating a highly processed diet, rarely exercising, or struggling with untreated sleep apnea, your body isn't ignoring testosterone.

It's responding to the priorities you've unintentionally given it.

That's not failure. It's physiology.

Sleep provides one of the clearest examples. Even a few nights of inadequate sleep can reduce testosterone production while increasing cortisol, impairing insulin sensitivity, disrupting appetite regulation, and slowing recovery. Untreated sleep apnea compounds those effects by repeatedly interrupting restorative sleep throughout the night. Many men assume snoring is simply an annoyance for their spouse, when in reality it may be one of the most important clues explaining why they feel exhausted during the day.

Body composition tells a similar story. Visceral fat isn't simply stored energy—it's metabolically active tissue that influences inflammation, insulin sensitivity, and hormone metabolism. As visceral fat increases, testosterone often declines. Lower testosterone then makes preserving muscle and losing fat more difficult, creating a cycle that quietly reinforces itself over time.

Fortunately, that cycle can often work in the opposite direction.

Improving sleep, building muscle, reducing visceral fat, managing stress, and correcting nutritional deficiencies don't simply improve your general health—they often improve the hormonal environment as well. Sometimes testosterone levels rise naturally because the body is no longer working against an unhealthy environment.

That's one of the reasons I don't separate hormone health from metabolic health.

They're part of the same conversation.

Nutrition follows the same principle, although perhaps not in the way social media suggests. There isn't a single "testosterone food" that transforms hormone levels overnight. If there were, every endocrinologist would simply prescribe steak and eggs. What consistently matters is eating enough high-quality protein to preserve muscle, consuming healthy fats that support hormone production, maintaining a healthy body composition, and avoiding the cycle of chronic calorie restriction followed by overeating.

The body doesn't thrive on extremes. It thrives on consistency.

Supplements deserve a similarly balanced perspective. Every month seems to produce another "revolutionary" testosterone booster promising dramatic results. Most ultimately fall into one of two categories: they either correct a genuine deficiency or they overpromise. Vitamin D, magnesium, or zinc may help when deficiencies exist. Certain botanicals, such as ashwagandha or tongkat ali, have shown modest benefits in selected studies, but the effects are generally small and the evidence remains mixed. None of them consistently replace testosterone in men with true hypogonadism.

When I recommend supplements, it's because they fit an individual's physiology—not because they're trending online.

That's an important distinction.

The internet often asks,

"What supplement raises testosterone?"

I'm usually asking a different question.

"Why did testosterone become low in the first place?"

The answers to those two questions often lead to very different treatment plans.

By this point, we've usually learned something important.

Sometimes low testosterone is the primary problem. Sometimes it's one consequence of a much larger physiologic picture. Understanding the difference is what makes treatment personal rather than protocol-driven.

That understanding begins long before we talk about injections, or oral prescriptions.

It begins by asking better questions.

When Testosterone Really Is the Answer

After spending the last several pages discussing sleep, nutrition, body composition, and lifestyle, you might wonder whether I'm trying to talk people out of testosterone.

Quite the opposite.

One of the biggest misconceptions about thoughtful hormone therapy is that clinicians fall into one of two camps: they prescribe testosterone to nearly everyone with a low laboratory value, or they refuse to prescribe it altogether. I don't think either approach serves patients particularly well.

The goal isn't to avoid testosterone. The goal is to use it when it has the greatest opportunity to improve someone's life.

There are men who do everything right. They prioritize sleep, exercise consistently, maintain a healthy weight, eat well, and still develop true testosterone deficiency. Others have primary hypogonadism, pituitary disorders, prior chemotherapy, testicular injury, or other medical conditions that impair hormone production. In those situations, testosterone isn't a shortcut around healthy living. It's replacing a hormone the body can no longer produce in adequate amounts.

When prescribed appropriately, TRT can improve libido, erectile function, lean muscle mass, bone density, anemia in selected men, and overall quality of life. More importantly, many patients describe something that's difficult to measure on a laboratory report: they simply begin to feel like themselves again. They wake up with more energy, recover more easily from exercise, regain enthusiasm for activities they once enjoyed, and discover that the version of themselves they thought was gone had simply been buried beneath months—or years—of untreated hormone deficiency.

That said, testosterone is not a fountain of youth.

It won't replace eight hours of sleep. It won't undo years of inactivity. It won't compensate for a poor diet, chronic alcohol use, or unmanaged stress. Good hormone therapy isn't about creating superhuman physiology.

It's about restoring normal physiology whenever possible.

As Dr. Peter Attia often reminds us, the goal isn't simply to extend lifespan—it's to extend healthspan. Hormone therapy should help you remain active, engaged, and capable throughout your life, not simply produce a higher testosterone level on a laboratory report.

That's an important distinction because I don't measure success by how high someone's testosterone becomes.

I measure success by whether they feel healthier, think more clearly, recover better, and are more present for the people and activities that matter most.

The Questions Everyone Asks

By this point, most people have stopped asking whether testosterone works.

Instead, they start asking the questions that really matter.

Is it safe?

Will it increase my risk of prostate cancer?

What about my heart?

Will it affect my fertility?

They're exactly the questions they should be asking. Testosterone replacement isn't something to fear, but it shouldn't be something to take casually either. Like every meaningful medical decision, it deserves an honest discussion about both benefits and risks.

Prostate Cancer

Perhaps no topic has created more confusion than the relationship between testosterone and prostate cancer.

For years, men were told that increasing testosterone would inevitably fuel prostate cancer growth. That concern stemmed from early observations showing that advanced prostate cancer often responded to lowering testosterone levels. Somewhere along the way, that observation evolved into the belief that replacing testosterone must therefore cause prostate cancer.

It was a reasonable hypothesis. It simply hasn't been supported by the evidence.

Over the past two decades, our understanding has changed considerably. Large observational studies, randomized clinical trials, and more recent analyses have not shown that appropriately prescribed testosterone therapy increases the overall risk of developing prostate cancer in carefully selected and monitored men. That doesn't mean prostate health becomes irrelevant. It means we can replace fear with thoughtful screening, shared decision-making, and ongoing monitoring.

If you're considering TRT, we'll review your personal and family history, discuss prostate health, determine whether PSA testing is appropriate, and continue monitoring over time. Medicine rarely deals in absolutes, but today's evidence allows for a far more balanced conversation than many men heard twenty years ago.

Cardiovascular Health

The conversation surrounding heart health has followed a similar path.

If you searched the internet a decade ago, you could easily find headlines claiming testosterone was either dangerous for the heart or protective against heart disease. The truth, as is often the case in medicine, lies somewhere in the middle.

The landmark TRAVERSE Trial, which followed more than 5,000 men with confirmed hypogonadism (low testosterone) and elevated cardiovascular risk, helped answer many of these questions. Reassuringly, testosterone therapy did not increase the overall rate of major cardiovascular events compared with placebo when prescribed and monitored appropriately.

At the same time, the study reminded us that no medication is entirely without risk. Certain adverse events—including elevated hematocrit, atrial fibrillation, and pulmonary embolism—occurred more frequently in some patients.

That finding doesn't make testosterone dangerous. It reinforces something much more practical.

Good follow-up is part of the treatment.

Fertility

One conversation should never be overlooked.

Fertility.

Many men understandably assume that because testosterone improves sexual function, it must also improve fertility.

Ironically, the opposite is often true.

External testosterone signals the brain that adequate hormone is already present. In response, the brain reduces its own stimulation of the testicles, and sperm production can decline significantly. For men who hope to have children—whether next year or five years from now—that changes the treatment strategy entirely.

Fortunately, alternatives and fertility-preserving approaches exist, but they work best when those goals are discussed before treatment begins rather than after.

Choosing the Right Treatment

Choosing the Right Form of Testosterone

Once we've determined that testosterone replacement is appropriate, the next question is usually straightforward.

"What's the best way to take it?"

Fortunately, there isn't just one option.

For most men, testosterone injections remain the foundation of modern testosterone replacement therapy. They're reliable, relatively inexpensive, and allow precise dose adjustments as your symptoms and laboratory values change over time. Many men are understandably hesitant about giving themselves an injection at first, but most find that the process becomes surprisingly simple after a little instruction. Today, many patients use small subcutaneous injections that are quick, comfortable, and easy to perform at home.

Not everyone likes needles, however.

For men who prefer a needle-free option, oral testosterone has become an increasingly attractive alternative. Modern oral testosterone is very different from the older oral testosterone medications that carried concerns about liver toxicity. Today's FDA-approved oral testosterone undecanoate formulations are absorbed primarily through the lymphatic system rather than undergoing significant first-pass metabolism through the liver, making them a legitimate treatment option for carefully selected patients.

The tradeoff is convenience versus flexibility.

Oral therapy eliminates injections, but it requires taking medication consistently each day and may not provide the same degree of dose flexibility as injectable testosterone. It also tends to be more expensive and requires careful monitoring, including blood pressure, because some oral formulations have been associated with modest increases in blood pressure.

Neither option is inherently better.

For someone who values affordability, precise dose adjustments, and decades of clinical experience, injections are often an excellent choice. For someone who strongly prefers to avoid needles and is comfortable taking a daily medication, oral testosterone may be a better fit.

The best treatment isn't the one that's most popular online. It's the one that fits your physiology, your lifestyle, your goals, and your long-term health.

My Philosophy

If you've made it this far, you've probably noticed something.

I've spent remarkably little time trying to convince you to start testosterone. That was intentional.

I don't believe good medicine begins with a prescription. I believe it begins with understanding.

Every patient I evaluate starts with a comprehensive conversation designed to answer one question:

What story is your body trying to tell us?

Sometimes that story leads to testosterone replacement.

Sometimes it leads somewhere entirely different.

Quite often, it's a combination of both.

If testosterone replacement proves to be the right choice and your primary need is ongoing hormone management, my TRT program provides continued follow-up, laboratory monitoring, medication management, and individualized dose adjustments. For others, testosterone is only one chapter in a much larger story involving metabolism, sleep, nutrition, digestive health, mental wellness, or lifestyle. Those individuals often benefit from a broader strategy because lasting health rarely comes from optimizing a single hormone in isolation.

My goal isn't simply to prescribe testosterone.

It's to help you understand why your body changed in the first place and develop a plan that's both scientifically sound and realistic for your life.

Looking Beyond the Laboratory Value

When we first met, I asked you to imagine your car's check engine light coming on.

I'd like to end there as well. That warning light doesn't tell you what's broken. It simply asks you to pay attention.

Low testosterone often serves the same purpose. Sometimes the solution is straightforward. Sometimes testosterone replacement is exactly what's needed, and for the right person it can be genuinely life-changing. Other times, low testosterone is simply your body's way of pointing toward a problem that's been quietly developing beneath the surface.

The challenge isn't deciding whether testosterone is good or bad.

The challenge is understanding what your body is trying to tell you.

That's the kind of medicine I believe in. Not because it's the fastest approach, and certainly not because it's the easiest, but because lasting health has rarely been built by chasing a single laboratory number. It's built by asking better questions, understanding the whole story, and creating a plan that reflects both the science and the person sitting across from me.

After all, the goal was never simply to fix the warning light.

The goal was to take care of the engine.

If this way of thinking resonates with you, I'd be honored to help you understand what your body is trying to tell you.

• Bhasin S, et al. Testosterone Therapy in Men With Hypogonadism: An Endocrine Society Clinical Practice Guideline. Journal of Clinical Endocrinology & Metabolism. 2018.

• Mulhall JP, et al. Evaluation and Management of Testosterone Deficiency: American Urological Association Guideline. American Urological Association. Updated 2024.

• Lincoff AM, et al. Cardiovascular Safety of Testosterone-Replacement Therapy (TRAVERSE Trial). New England Journal of Medicine. 2023.

• Snyder PJ, et al. The Testosterone Trials. New England Journal of Medicine. 2016.

• European Association of Urology. Guidelines on Sexual and Reproductive Health – Male Hypogonadism. Current edition.