Low Testosterone in Men After 40: What Every Man Should Know

An Evidence-Based Guide to Functional Male Wellness

Most men don’t talk about hormones. Not to their doctors. Not to their friends. And often, not even to themselves. But somewhere between the fatigue, poor sleep, slowing metabolism, shrinking muscle mass, low motivation, belly weight, and changes in performance—men over 40 start to wonder:

“Is this just getting older… or is something going on?”

The answer? Something is going on. And it has a name: andropause (low testosterone).

In this post, we’ll take a functional medicine approach to understanding low testosterone and andropause in men after 40—unpacking how hormone decline is influenced by chronic stress, poor sleep, blood sugar imbalance, and metabolic slowdown. You’ll learn the early warning signs of testosterone deficiency, how it impacts muscle, mood, and motivation, and most importantly, what can be done to restore vitality. We’ll also explore the interconnected systems that support or sabotage hormone balance—like the liver, mitochondria, and adrenal health—and outline practical, natural strategies to get back on track.

What Is Andropause? (Yes, It’s Real)

Just as women experience menopause, men go through andropause—a progressive, age-related decline in testosterone and other key androgens such as DHEA and pregnenolone. This shift often begins subtly in the late 30s to early 40s and progresses over time. But unlike the more abrupt hormonal changes seen in menopause, andropause unfolds gradually, often going unrecognized for years. Because there is no clear biological marker like the cessation of menstruation, many men don’t realize what’s happening until symptoms accumulate: energy dips, mental sharpness fades, motivation wanes, and libido declines.

What’s more, these changes are frequently brushed off as “normal aging”—yet they often stem from correctable hormonal imbalances. When addressed early, andropause doesn’t have to mean a slow decline—it can be the entry point to a more informed and revitalized chapter of health.

Andropause isn’t “low T” marketing hype. It’s a real biological transition with measurable consequences.

Common symptoms include:

• Decreased energy + stamina
• Loss of muscle mass + increased belly fat
• Irritability, low mood, or anxiety
• Memory lapses or brain fog
• Declining libido + erectile function
• Poor focus + motivation
• Joint stiffness or slower workout recovery
• Nighttime urination, disrupted sleep or sleep apnea
• Lower resilience to stress + life’s demands

If you’re nodding along, you’re not alone. Some estimates suggest up to 25 million American men between ages 40 and 55 are experiencing symptoms of andropause—but most aren’t getting proper evaluation or support.

Testosterone: More Than a Sex Hormone

Testosterone isn’t just about libido or gym gains. It’s a core metabolic hormone—your body’s internal command center that influences much more than most men realize. From brain function to blood sugar regulation, muscle integrity to cardiovascular tone, testosterone has a hand in nearly every system that keeps a man feeling strong, clear-headed, and resilient.

Testosterone naturally peaks in your 20s and begins a gradual decline of 1–2% per year starting around age 30. But under chronic stress, poor sleep, blood sugar imbalance, and environmental toxins, this decline can accelerate. We are also seeing this occur even in younger men in their 20s.

Functional medicine sees testosterone as:

• An anabolic hormone – preserves lean muscle and bone
• A metabolic hormone – improves insulin sensitivity and fat metabolism
• A neurological hormone – stabilizes mood, drive, and cognition
• A sexual health hormone – supports libido and performance

Here’s the rub: many men test “normal” for their age because conventional labs adjust reference ranges downward over time. But “normal” isn’t the goal—optimal is. In functional medicine, we use ranges based on youthful physiology, not statistical averages of aging populations.

Why Testosterone Falls Faster Than It Should

If your testosterone is lower than it should be, it’s often not just a gonadal issue—it’s a systems issue. The following disruptors are common and cumulative:

• Chronic stress increases cortisol, which downregulates testosterone production at the brain level. High cortisol directly suppresses the hypothalamic-pituitary-gonadal axis, reducing testosterone output.
• Poor sleep, especially inadequate deep sleep, interferes with the body’s natural testosterone synthesis—most of which occurs between 2–6 a.m. Testosterone is produced during deep sleep. One week of 5–6 hour nights can reduce T levels by 10–15%.
• Insulin resistance and high blood sugar increase aromatase activity, which converts testosterone into estrogen.
• Liver dysfunction slows clearance of bound hormones, elevates SHBG (sex hormone-binding globulin), and decreases free (usable) testosterone.
• Environmental toxins—from BPA in plastics to pesticides and parabens in personal care products—act as xenoestrogens, disrupting endocrine signaling and driving hormonal imbalance.

The result? A hormonal environment that not only suppresses testosterone but actively converts it into other less beneficial hormones—all while robbing the body of its energy, clarity, and natural strength.

This is why many men in their 40s and 50s feel like they’ve “lost their edge”—not due to age alone, but due to a perfect storm of metabolic stressors that suppress their most vital hormone.

How to Support Testosterone Naturally

The good news? You can restore healthy testosterone levels without jumping straight to injections or hormone therapy. In fact, for many men in their 40s and 50s, the best first step isn’t replacement—it’s rebalancing. Functional medicine focuses on optimizing the terrain in which hormones are made, metabolized, and used.

Creating a hormonal environment that supports testosterone means looking upstream—at your sleep, blood sugar, stress response, nutrition, detox capacity, and daily rhythms. When the system is supported, testosterone often improves on its own.

Here’s where to begin:

1. Prioritize Deep, Consistent Sleep

Testosterone is primarily produced during deep, slow-wave sleep—especially between 2:00 and 6:00 a.m. If you’re burning the candle at both ends, or waking frequently, your testosterone production is likely taking a hit.

Try this:

• Set a consistent bedtime and wake time (even on weekends)
• Eliminate screens 1–2 hours before bed to support melatonin
• Ensure your bedroom is cool, dark, and quiet
• Consider magnesium threonate or glycinate, or a nighttime support like Lipocalm or GABA + L-theanine blends
• Address sleep apnea if snoring, poor oxygenation, or daytime fatigue is present

Even one week of reduced sleep has been shown to lower testosterone levels by up to 10–15%

2. Train With Intention: Muscle = Hormonal Currency

Muscle mass isn’t just about looking fit—it’s a metabolically active organ that keeps blood sugar in check, supports mitochondrial output, and helps maintain testosterone levels.

Your best bet?

• Strength train 2–4x/week using compound movements (squats, deadlifts, presses)
• Focus on progressive overload, not just cardio
• Keep workouts under 60 minutes to avoid excess cortisol
• Prioritize recovery with protein, minerals, and rest

Strength training has consistently been shown to increase both total and free testosterone naturally

3. Stabilize Blood Sugar

Insulin resistance is one of the most common drivers of low testosterone in men after 40. When blood sugar is unstable, aromatase activity increases, converting testosterone into estrogen—particularly in visceral fat tissue.

Support blood sugar by:

• Eating protein (30–40g) with every meal
• Avoiding late-night snacks and refined carbs
• Balancing meals with fiber, fat, and quality carbs like root vegetables or berries
• Walking after meals to enhance insulin sensitivity

Supplemental support may include:

• Chromium
• Berberine
• Alpha-lipoic acid
• Apex’s Glysen or Adaptocrine, depending on symptom presentation

4. Detox Your Hormone Environment

Many men unknowingly live in a sea of estrogen-mimicking chemicals (xenoestrogens). These compounds interfere with androgen signaling, increase SHBG, and disrupt healthy hormone metabolism.

Minimize exposure by:

• Avoiding plastics for food and drink (especially when heated)
• Choosing glass or stainless steel containers
• Switching to paraben- and phthalate-free personal care products
• Buying organic when possible to reduce pesticide exposure
• Supporting liver detoxification with cruciferous vegetables, dandelion root, sulforaphane (e.g., Sulforaxym)

The liver plays a key role in hormone clearance—especially estrogen and SHBG. A burdened liver means bound-up testosterone.

5. Replenish Key Nutrients

Testosterone production is nutrient-intensive. Many men with low testosterone are deficient in the very nutrients needed to support it. Here are a few key players:

• Zinc – cofactor for testosterone synthesis and sperm production; also inhibits aromatase ~ (oysters, beef, pumpkin seeds)
• Magnesium – supports deep sleep, insulin sensitivity, and stress regulation
• Vitamin D3 – low D is directly associated with low testosterone; regulates the HPG axis and supports testosterone synthesis
• B vitamins – crucial for adrenal and methylation function; especially B6, which aids androgen metabolism and neurotransmitter balance
• L-carnitine – supports mitochondrial energy and sperm motility
• CoQ10 – vital for ATP production and cellular energy—especially after statin use

Consider professional-grade supplements or work with a practitioner to tailor support based on labs.

6. Don’t Underestimate Stress Management

Chronic stress doesn’t just make you feel tired—it shifts hormone production away from testosterone and toward survival hormones like cortisol. Over time, this suppresses the entire testosterone production axis (the HPG axis).

Simple but powerful stress regulators include:

• Morning sunlight and movement
• Deep breathing or breathwork
• Cold exposure or sauna (used appropriately)
• Adaptogenic herbs like ashwagandha, rhodiola, or eleuthero
• Daily practices that create structure and meaning—your nervous system needs rhythm to feel safe

Bottom Line

You don’t need to jump straight to hormone replacement to feel better. Start by restoring the foundational systems that support testosterone: sleep, metabolism, muscle mass, detox, and micronutrient status. When these are in place, hormone levels often improve naturally—and more importantly, they become sustainable long-term.

Want to take it further? Functional lab testing can clarify where your imbalances are—and help you customize a plan that rebuilds your strength, energy, and drive from the inside out.

Labs That Matter

Functional labs offer insight long before conventional tests flag disease. If you’re experiencing symptoms, these are the labs worth asking for:

Mitochondria, Muscles + Testosterone-Energy Connection

Energy isn’t just about caffeine, carbs, or how much sleep you got last night. It’s about mitochondrial efficiency—your body’s ability to convert nutrients and oxygen into cellular energy, or ATP (adenosine triphosphate). These tiny powerhouses sit inside every cell, but they’re especially concentrated in metabolically active tissue like muscle and brain.

And here’s the catch: testosterone is a mitochondrial hormone. It influences how well mitochondria function, how much energy you produce, and how resilient your body feels on a daily basis.

Low Testosterone = Low Mitochondrial Output

Testosterone has been shown to:

• Stimulate mitochondrial biogenesis (the creation of new mitochondria)
• Enhance oxygen delivery through red blood cell production
• Support fat oxidation and fuel metabolism in muscle cells
• Regulate nitric oxide levels for better blood flow and cellular nutrient delivery

When testosterone drops—as it often does in men over 40—mitochondrial performance suffers. The result?

• Chronic fatigue
• Poor workout recovery
• Decreased endurance
• Muscle loss + weakness
• Mental fatigue + brain fog

This is one reason why so many men with low testosterone say, “I’m doing everything right, but I still feel exhausted.” Their mitochondria aren’t responding the way they used to—because testosterone is no longer supporting their function.

Muscle Mass: Your Mitochondrial and Hormonal Bank Account

It’s not just about supporting mitochondria to improve testosterone. It works in the opposite direction too.

Skeletal muscle is one of your most metabolically protective organs. It’s the largest site of glucose disposal, a reservoir for amino acids, and a buffer for inflammatory cytokines. It also houses thousands of mitochondria—and actively contributes to testosterone maintenance.

When you lose muscle, you lose:

• Mitochondrial density
• Insulin sensitivity
• Testosterone-regulating enzymes
• Physical resilience

Maintaining and building muscle not only improves mitochondrial efficiency—it stimulates hormonal balance, enhances androgen receptor sensitivity, and directly supports your testosterone-producing feedback loop.

Support the Testosterone–Mitochondria Axis by:

Lifting heavy things (compound strength training 3–4x/week)

Eating enough protein (30–40g per meal for most men)

Reducing oxidative load (mitochondria are vulnerable to oxidative stress from inflammation, alcohol, sugar, and toxins)

Supporting mitochondrial cofactors:

• Alpha-lipoic acid – recycles glutathione and supports mitochondrial antioxidant defense
• Magnesium – required in over 300 enzymatic reactions including ATP synthesis
• L-carnitine – helps shuttle fatty acids into mitochondria for energy
• CoQ10 to power ATP production
• Creatine – improves muscular and mental energy output

It’s a Two-Way Street

Build muscle to protect your mitochondria.
Support mitochondria to preserve your testosterone.
Protect testosterone to sustain your energy, strength, and longevity.

This cycle is at the heart of healthy aging in men. And it’s also the reason why addressing testosterone in isolation—without looking at mitochondrial health and muscle preservation—often fails to produce lasting results.

The Cholesterol Myth (And What You Should Really Be Looking At)

If your LDL is slightly elevated, you may have been handed a statin prescription—no questions asked. This “treat the number” approach is common, but in functional medicine, we dig deeper. Because testosterone and cholesterol metabolism are intricately linked—and an elevated LDL level doesn’t always equal cardiovascular risk.

Cholesterol is not the enemy. It’s the raw material your body uses to make hormones—including testosterone, DHEA, cortisol, and estrogen. It also supports:

• Cell membrane integrity
• Bile acid production for fat digestion
• Vitamin D synthesis
• Brain health + neurotransmission

In fact, excessively lowering cholesterol (especially total cholesterol <150) has been associated with:

• Hormonal imbalance
• Depression + mood instability
• Sexual dysfunction
• Memory loss + cognitive decline

Cholesterol + Testosterone: The Hormonal Connection

Testosterone is synthesized from pregnenolone, which is made from cholesterol. If cholesterol is too low—or if liver function is impaired—hormone production may slow.

Statins work by blocking HMG-CoA reductase, the enzyme your body uses to make cholesterol. But this also reduces the production of CoQ10, a mitochondrial nutrient essential for energy and heart function. This is one reason many men on statins experience fatigue, low libido, muscle aches, or even mood changes.

In short: if your testosterone is low and you’re on a statin, the two may be connected.

The Labs That Tell the Real Story

LDL alone is a blunt tool for assessing cardiovascular risk. What matters more is context—inflammation, insulin levels, particle size, and oxidative status.

Here’s what to ask for:

Rethink “High Cholesterol” in Functional Context

Rather than rushing to suppress LDL, ask:

• Why is it elevated? (insulin resistance, inflammation, poor detox?)
• Is it oxidized or small-particle LDL?
• What’s happening with liver clearance, hormone balance, and mitochondrial function?

If cholesterol is elevated alongside elevated insulin, hs-CRP, and poor sleep, then yes—it may be time for intervention. But if it’s modestly elevated in an otherwise healthy, active, insulin-sensitive man, it may be part of a compensatory hormonal effort—not a threat.

Statins and the Midlife Male

For men in their 40s and 50s with symptoms of low testosterone, fatigue, memory issues, or loss of motivation, it’s worth asking:

• Has cholesterol been lowered too far?
• Is hormone production being unintentionally suppressed?
• Could mitochondrial fatigue (from CoQ10 depletion) be part of the issue?

In many cases, functional support—lifestyle changes, blood sugar balance, liver support, and mitochondrial nutrients—improves both cardiovascular and hormonal markers without shutting down your body’s hormone production pathway.

Closing Thoughts: The New Definition of Strength

Strength isn’t just about lifting weights. It’s about recovering well, handling stress, and waking up ready for the day. It’s about energy that lasts, mood that holds steady, and motivation that returns.

If you’re feeling off, don’t accept it as “just aging.” Andropause is real—but it’s also reversible. With the right tools, data, and guidance, men can rebuild vitality from the inside out.

It’s time to bring male hormone health into the open. And to remind men that strength isn’t lost. It just needs to be recalibrated.

Strength is no longer just about how much weight you can lift—it’s about how resilient your body is under pressure.

Functional medicine isn’t about fixing what’s broken. It’s about restoring what’s missing: rhythm, nutrients, clarity, and a roadmap. Men don’t need another lecture or quick-fix supplement—they need data, insight, and tools that actually work.

If you’re tired, irritable, losing your edge, or just not feeling like yourself, it’s time to listen. Your body is asking for more than a multivitamin and a protein shake.

Grab a complimentary copy of my Immune Boosting Foods guide here.

Interested In Learning How To Increase Your Testosterone Naturally?

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