Why am I tired all the time?
Because fatigue is the least specific symptom in medicine, and you cannot tell the cause from how it feels. In men the usual candidates are sleep quantity and quality including undiagnosed sleep apnea, anemia, thyroid disease, depression, alcohol, medications and blood sugar, with low testosterone as one candidate among them. The first move is a clinician and blood work, not a purchase.
What actually causes fatigue in men
Persistent tiredness is the symptom that shows up in almost every condition, which is exactly why the internet is full of pages confidently telling you it is one thing. It is more useful to hold the whole list at once, then narrow it with a clinician and a blood draw.
| Cause | What points towards it | How it gets checked |
|---|---|---|
| Not enough sleep | You are averaging under seven hours, or your schedule shifts around | A sleep diary for two weeks. The cheapest test on this list, and often the answer |
| Obstructive sleep apnea | Heavy snoring, witnessed pauses in breathing, waking unrefreshed after enough hours, morning headache, nodding off in the afternoon. Very commonly missed in men | A sleep study, at home or in a lab, arranged by a clinician |
| Anemia or iron deficiency | Breathlessness on stairs, pale appearance, poor exercise tolerance, sometimes a history of blood loss | A full blood count and ferritin |
| Thyroid disease | Cold intolerance, weight change, dry skin, constipation, slowed thinking | A TSH test, with further thyroid tests if abnormal |
| Depression or anxiety | Loss of interest in things you used to enjoy, early waking, low mood, poor concentration. Fatigue is often the presenting complaint rather than sadness | A clinical conversation. There is no blood test for it |
| Alcohol | Drinking most nights, even moderately. It fragments sleep architecture whether or not you feel hungover | An honest history, and four weeks off to see |
| Medications | Fatigue that began within weeks of a new prescription. Beta blockers, antihistamines, some antidepressants, opioids and others | A medication review with the prescriber who wrote them |
| Blood sugar and metabolic health | Excess weight around the middle, thirst, frequent urination, family history of type 2 diabetes | HbA1c or fasting glucose, plus a metabolic panel |
| Low testosterone | Fatigue together with reduced sex drive, fewer morning erections, lost muscle and easier fat gain | A morning blood test, repeated on a second separate morning, read with your symptoms |
| Something less common | Kidney or liver disease, coeliac disease, chronic infection, sleep disorders other than apnea, and more | Guided by your history and the results of the basic panel |
Not exhaustive, and more than one of these is often true at the same time. Use it to prepare for a consultation, not to diagnose yourself.
The one most commonly missed: sleep apnea
If there is a single reason to read this page, it is this one. Obstructive sleep apnea is common in men, particularly with excess weight around the neck and middle, and a large share of cases are undiagnosed. It fragments sleep hundreds of times a night without you remembering any of it, so the hours in bed look fine while the sleep itself is not.
It also produces the exact symptom cluster that gets attributed to hormones: daytime fatigue, mental fog, low mood, irritability and reduced sex drive. On top of that, untreated apnea lowers testosterone on its own, which means it can produce both the symptoms and a low lab result while remaining the actual problem. Treating the apnea is what changes the picture. Prescribing testosterone into untreated apnea can make the apnea worse.
- Ask your partner. Loud snoring and witnessed pauses in breathing are the strongest signals, and you will not observe either yourself.
- Waking unrefreshed after seven or eight hours is more telling than not getting enough hours.
- Morning headaches, dry mouth, and nodding off while sitting still during the day all point the same way.
- Ask a clinician about a sleep study. Home testing is straightforward now, and treatment changes energy, mood and cardiovascular risk together.
What blood work usually comes first
For persistent fatigue, a clinician generally starts with a small, cheap panel that rules out the common and treatable causes before anything more exotic. Knowing what to expect makes the appointment more productive:
- Full blood count and ferritin, for anemia and iron deficiency
- TSH, for thyroid function
- HbA1c or fasting glucose, for blood sugar
- Kidney and liver function, and electrolytes, as a general screen
- Vitamin D and B12, where the history suggests it
- Morning total testosterone, repeated on a second separate morning if the first is low and your symptoms fit, usually alongside free testosterone, LH and FSH
That sequence is deliberate. The testosterone question is on the list, not at the top of it, because the tests above it are cheaper, faster and more often the answer.
Could it be low testosterone?
It could, and it is worth testing properly if the picture fits. What makes the picture fit is not fatigue on its own, it is fatigue arriving alongside the more specific symptoms: reduced sex drive, fewer morning erections, loss of muscle and strength despite unchanged training, and easier fat gain around the middle.
Diagnosis is a morning blood test repeated on a second separate morning, read by a licensed provider alongside your symptoms and a wider panel. Testosterone therapy is prescribed for men with hypogonadism confirmed by lab testing, and the FDA has specifically cautioned against using testosterone products for age-related low levels alone. The detail is in what are the symptoms of low testosterone, and if your labs do confirm it, how long TRT takes to work sets realistic expectations.
A clinic willing to prescribe testosterone from a fatigue questionnaire is skipping the step that makes it safe. If your tiredness is coming from sleep apnea, anemia or depression, testosterone is the wrong treatment and can delay the right one.
What a consult covers, and what it will not sell you
This page is deliberately not a product pitch, because fatigue is not a product problem. What a free call with a health specialist does is work out what should be checked, and a US-licensed provider then reviews:
- Your sleep, including snoring, witnessed pauses and daytime sleepiness
- Your mood, stress and what has changed in the last year
- Alcohol, and your full medication list
- Weight, blood sugar and cardiovascular history
- Which blood tests are worth running, and how to interpret what comes back
- Whether hormone therapy is even relevant to you, including the answer that it is not
Where labs confirm hypogonadism and a provider agrees therapy is appropriate, testosterone at Expert Health is from $129 per month on the 3-month plan ($387 total), or $150 month to month, with follow-up labs and check-ins included. Where they do not, the provider says so.
If you are considering NAD+ for energy, read NAD+ for men first. Precursors reliably raise blood NAD+, and rigorous trials have largely failed to confirm that this improves fatigue. That is worth knowing before you spend anything.
When tiredness needs a doctor sooner
See a clinician promptly if
- You have lost weight without trying
- You are breathless, or your chest feels tight on exertion
- You have night sweats, fevers, or a persistent cough
- You have noticed blood in your stool or urine, or unusually dark stools
- A lump, a new persistent pain, or swollen glands have appeared
- The fatigue came on abruptly and severely, or you are falling asleep while driving
Worth changing while you wait
- Give sleep a genuine seven to eight hours, on a consistent schedule, for four weeks
- Take four weeks off alcohol and see what changes
- Move daily, even briefly. Deconditioning makes fatigue worse, not better
- Eat regularly, with protein, rather than running on coffee
- Write down when the tiredness started and what else changed then, which is the most useful thing you can bring to an appointment
None of that replaces the workup. It makes the workup cleaner, and occasionally it makes it unnecessary.
Frequently asked questions
Why am I tired all the time as a man?
Is my tiredness low testosterone?
What blood tests should I ask for if I am always tired?
Could sleep apnea be causing my fatigue?
Can depression cause physical tiredness?
Will NAD+ or a supplement fix my low energy?
How long should I be tired before seeing a doctor?
Does alcohol cause fatigue even in moderate amounts?
Sources
- FDA cautions about using testosterone products for low testosterone due to aging · U.S. Food and Drug Administration
- Testosterone therapy in men with hypogonadism, clinical practice guideline · Endocrine Society
- Testosterone deficiency guideline · American Urological Association
- Effects of nicotinamide riboside on NAD+ levels, cognition, and symptom recovery in long-COVID: a randomized controlled trial · eClinicalMedicine, via PubMed, 2025
This article is for general educational purposes and is not medical or legal advice. Statements have not been evaluated by the FDA, and treatments referenced are not intended to diagnose, treat, cure, or prevent any disease. Compounded medications are not FDA-approved. Individual results vary. Always consult a licensed provider before starting any treatment.
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