Does testosterone increase metabolism in men?

Many men hear that more testosterone means a faster metabolism and effortless fat loss. In reality, testosterone can nudge metabolism in the right direction for men with true deficiency, but the payoff depends heavily on muscle, movement, diet, and sleep.

The relationship

When guys ask “does testosterone increase metabolism,” what they really want to know is whether fixing their hormones will make it easier to lose fat and gain energy. Metabolism is the sum of all the chemical processes that turn food and stored fuel into energy and heat. Most of your daily burn comes from basal metabolic rate, the calories you use just to stay alive.

Testosterone is the primary male sex hormone. It is made mainly in the testes and helps regulate muscle mass, fat distribution, red blood cell production, mood, and sex drive. Large population studies show that men with lower testosterone are more likely to have more belly fat, higher blood pressure, higher triglycerides, and a cluster of problems called metabolic syndrome.^[1]

On the flip side, randomized controlled trials of testosterone replacement therapy (TRT) in men with low testosterone find consistent changes in body composition: more lean mass and less fat mass over 6 to 12 months.^[2],[3] Meta-analyses also report small improvements in waist circumference, fasting blood sugar, and cholesterol in hypogonadal men, suggesting testosterone can support a healthier metabolic profile when levels are truly low.

Those benefits are not automatic. Trials where men on TRT also lifted weights, ate adequate protein, and improved sleep show the biggest jumps in muscle and drops in fat. In contrast, giving testosterone to men who already have normal levels produces little or no metabolic advantage and may increase risks such as thickened blood and prostate issues.^,[4]

So does testosterone increase metabolism in men? In men with confirmed low testosterone and symptoms, bringing levels back into the normal range can modestly raise metabolic rate, mainly by increasing muscle and trimming visceral fat. It is a helpful tool for the right patient, not a stand-alone weight-loss solution.

How it works

Testosterone touches several levers that control how a man’s body burns calories and manages fuel. Here is how it affects metabolism under the hood.

More muscle, higher resting burn

Testosterone is an anabolic hormone, meaning it signals the body to build and preserve lean tissue like skeletal muscle. In men with hypogonadism — chronically low testosterone — TRT increases muscle protein synthesis and fat‑free mass, which slightly raises basal metabolic rate, the calories you burn at rest.^[2]

Less visceral fat, better insulin sensitivity

Low testosterone in men is strongly linked to more visceral fat, the deep fat around the organs that drives inflammation and insulin resistance, which is the body’s reduced ability to move sugar from blood into cells.^[1] In controlled trials, TRT modestly reduces waist size and visceral fat and improves markers like fasting glucose and insulin, suggesting better insulin sensitivity and healthier carbohydrate handling.

Motivation, mood, and movement

Testosterone acts in brain regions that regulate motivation, reward, and fatigue, which is a sense of low energy and tiredness. Men starting TRT often report more drive to be active, and trials in older hypogonadal men show improved physical function and walking distance that likely reflect moving more in daily life.^[3]

Mitochondria and fuel use

Mitochondria are tiny structures inside cells that act like power plants, turning fat and sugar into usable energy. Laboratory and small human studies suggest testosterone supports mitochondrial function and may lower harmful free fatty acids in the blood, helping cells burn fuel more cleanly and efficiently, although this evidence is less robust than the data on muscle and fat mass.

When low testosterone is truly low

Guidelines based on meta-analyses indicate that symptomatic men with total testosterone below 350 ng/dL (≈12 nmol/L) are most likely to benefit from TRT; if total testosterone is borderline, free testosterone below 100 pg/mL (≈10 ng/dL) supports a diagnosis of hypogonadism, the medical term for chronically low testosterone.^[4] In practice, experienced clinicians use 350 ng/dL for total or 100 pg/mL for free testosterone as working decision thresholds when symptoms persist, because above these levels metabolic gains from extra testosterone are usually small.

Conditions linked to it

Low testosterone does not just affect sex drive and strength. It sits at the crossroads of several conditions that slow metabolism and increase long‑term health risks in men.

• Obesity and central belly fat. Men with lower testosterone are more likely to carry fat around the abdomen, and obesity itself further suppresses testosterone, creating a vicious cycle that drags down metabolic rate.^[1]
• Metabolic syndrome and type 2 diabetes. Metabolic syndrome is a cluster of high waist size, high blood pressure, abnormal cholesterol, and high fasting sugar. Meta-analyses show men with low total or free testosterone have a much higher risk of metabolic syndrome and type 2 diabetes, and TRT can modestly improve blood sugar control in men who are both hypogonadal and insulin resistant.^[1]
• Nonalcoholic fatty liver disease (NAFLD). NAFLD is excess fat stored in the liver that is not due to heavy alcohol use. Observational studies find men with the lowest testosterone levels are more likely to have fatty liver and worse liver enzyme tests, an important metabolic complication.
• Obstructive sleep apnea. Sleep apnea is when breathing repeatedly stops during sleep. It is tied to both low testosterone and weight gain; fragmented sleep worsens metabolic health, and excess fat around the neck and trunk can lower testosterone further, compounding fatigue.^,[5]
• Higher cardiometabolic risk and mortality. Systematic reviews link low testosterone with higher rates of cardiovascular events and all‑cause mortality in men, likely through a mix of more visceral fat, worse blood sugar, and unfavorable cholesterol patterns.

Limitations note: Most of these links come from observational studies. They show strong associations between low testosterone and poor metabolic health but cannot fully prove that low testosterone causes these conditions. In obesity and diabetes, the relationship is clearly two‑way.

Symptoms and signals

Because testosterone and metabolism are tightly linked, the signs of low testosterone often overlap with the signs of a sluggish metabolic engine. None of these symptoms prove a testosterone problem on their own, but together they are a reason to get evaluated.

• Gaining fat around the belly or chest even though your eating habits have not changed much
• Noticeable loss of muscle size or strength, or needing longer to recover between workouts
• Low energy, afternoon crashes, or feeling “wiped out” after normal daily tasks
• Reduced sex drive, fewer or weaker morning erections
• Brain fog, trouble focusing, or feeling less mentally sharp at work
• Worsening snoring, poor‑quality sleep, or waking up unrefreshed
• Lab results showing prediabetes, type 2 diabetes, high triglycerides, or fatty liver

If several of these are true and you are wondering “does testosterone increase metabolism enough to matter for me,” the next step is objective testing rather than guessing based on symptoms alone.

What to do about it

Improving metabolism with testosterone starts with a clear diagnosis, then layering hormone treatment on top of strong lifestyle foundations when it is appropriate. Here is a practical three‑step plan.

1. Get properly evaluated and tested. Ask your clinician for a focused exam and blood work if you have symptoms of low testosterone and sluggish metabolism. Total testosterone should be checked in the early morning on two separate days; if results are borderline, free testosterone can help clarify the picture. In practice, men with persistent symptoms and total testosterone below 350 ng/dL or free testosterone below 100 pg/mL are most likely to benefit from TRT.^[4] It is also wise to screen for fasting glucose or HbA1c, lipid profile, liver enzymes, thyroid function, and, when indicated, sleep apnea.
2. Fix the metabolic foundations first. Whether or not you start TRT, the biggest levers for metabolism are resistance training, nutrition, and sleep. Aim to lift weights at least 2 to 3 times per week, focusing on big movements like squats, presses, rows, and deadlifts. Eat enough protein — roughly 0.7 to 1.0 grams per pound of goal body weight — and build most meals around whole foods. Losing just 5 to 10 percent of body weight can raise testosterone on its own and improve insulin sensitivity, sometimes as much as medication.
3. Use testosterone therapy carefully, if it is truly indicated. TRT should be reserved for men with clear symptoms plus consistently low lab values, after discussing risks and benefits and ruling out causes like opioid use, pituitary disease, or uncontrolled sleep apnea.^[4] If you and your doctor decide to proceed, options include injections, gels, or longer‑acting formulations. Plan on regular follow‑up to track testosterone levels, blood counts, PSA (a prostate marker), cholesterol, and how your body composition and energy are changing over time.

Myth vs Fact: testosterone and metabolism

• Myth: Testosterone therapy melts fat even if you do not change your habits.
  Fact: Studies show TRT without training or diet changes produces only modest fat loss; the biggest shifts in metabolism happen when you combine testosterone with lifting, nutrition, and better sleep.^[2]
• Myth: The higher your testosterone, the faster your metabolism.
  Fact: Once testosterone is in the mid‑normal range, pushing it higher offers little extra metabolic benefit and may increase risks like thickened blood or acne.^,[4]
• Myth: Any tired middle‑aged man should “just try” testosterone to see if he feels better.
  Fact: Guidelines recommend TRT only when symptoms line up with two low morning tests; otherwise you risk side effects without solving the real problem.^[4]
• Myth: Over‑the‑counter “test boosters” are a safe way to raise testosterone and speed metabolism.
  Fact: Most supplements marketed as testosterone boosters have little high‑quality evidence, and some have been linked to liver injury or contaminated ingredients; lifestyle changes and proper medical care are far safer and more effective.

Bottom line

In men with genuine testosterone deficiency, restoring levels to a healthy range can modestly increase metabolism by building muscle, shrinking visceral fat, and improving how the body handles sugar and fats. For men whose levels are already normal, extra testosterone does not offer a meaningful metabolic edge and carries real risks. If you are asking “does testosterone increase metabolism for me,” the smartest move is to get properly tested, attack lifestyle foundations hard, and then consider TRT as one tool — not the only one — in a long‑term plan for better metabolic health.

References

1. Corona G, Monami M, Rastrelli G, et al. Testosterone and metabolic syndrome: a meta-analysis study. The journal of sexual medicine. 2011;8:272-83. PMID: 20807333
2. Isidori AM, Giannetta E, Greco EA, et al. Effects of testosterone on body composition, bone metabolism and serum lipid profile in middle-aged men: a meta-analysis. Clinical endocrinology. 2005;63:280-93. PMID: 16117815
3. Snyder PJ, Bhasin S, Cunningham GR, et al. Effects of Testosterone Treatment in Older Men. The New England journal of medicine. 2016;374:611-24. PMID: 26886521
4. Mulhall JP, Trost LW, Brannigan RE, et al. Evaluation and Management of Testosterone Deficiency: AUA Guideline. The Journal of urology. 2018;200:423-432. PMID: 29601923
5. Luboshitzky R, Aviv A, Hefetz A, et al. Decreased pituitary-gonadal secretion in men with obstructive sleep apnea. The Journal of clinical endocrinology and metabolism. 2002;87:3394-8. PMID: 12107256