Feeling permanently knackered is an excellent way to become interested in things you previously considered nonsense. Suddenly, a man on Instagram explaining the benefits of powdered mushrooms has your full attention.
He looks energetic. You’ve just forgotten why you walked into the kitchen. Perhaps he knows something.
But before buying whatever he’s holding, ask a more useful question: what exactly do you mean by tired? Struggling to stay awake, feeling physically drained and crashing after ordinary activity aren’t interchangeable experiences. They’re worth describing properly, because the details can help identify what needs investigating.
And there’s considerably more to investigate than whether you’ve eaten enough broccoli.
1. Describe the Problem Before Trying to Fix It
“I’m tired all the time” is a starting point. Getting specific makes it more useful.
Are you fighting sleep during meetings or while watching television? Are you awake but exhausted, with ordinary tasks taking far more effort? Or do you feel reasonably capable at first, then suffer a disproportionate slump afterwards?
For a few days, note when it happens, how long it lasts and what else comes with it. Include when it started: after an illness, a medication change, a new shift pattern or apparently out of nowhere. You’re gathering clues, not preparing a PowerPoint for your GP.
Pay particular attention to delayed crashes. If a walk, workout or busy day leaves you substantially worse hours or days later, mention that. This pattern, called post-exertional malaise, can occur with ME/CFS. It needs assessment rather than a motivational speech about getting off the sofa. Don’t keep increasing exercise through worsening symptoms.
Other symptoms help direct the conversation. Tiredness alongside unusual thirst and more frequent urination can warrant checks for diabetes. Feeling unusually cold, constipated and mentally sluggish can accompany an underactive thyroid. Breathlessness or palpitations may lead a clinician to investigate anaemia.
None of those combinations diagnoses anything from your armchair. They explain why “try a multivitamin” is sometimes a thoroughly inadequate response.
2. Look for the Things You Might Be Missing
You already know that five hours’ sleep isn’t ideal. The more interesting question is why you might feel dreadful after eight.
Sleep apnoea repeatedly disrupts breathing and sleep. Snoring is one clue, but NICE guidance also flags unrefreshing sleep, morning headaches, waking to urinate and problems with concentration or memory. You don’t have to remember waking up for your sleep to have been disturbed.
Ask your partner whether they’ve noticed pauses in breathing or gasping. If the pattern sounds familiar, discuss it with your GP. Investigation can involve overnight monitoring at home. A normal bedtime doesn’t rule out a sleep disorder, and an energy supplement won’t keep your airway open.
Next, check the medicine cupboard. Some antihistamines cause drowsiness, including ingredients used in certain sleep aids and cold remedies. Even antihistamines labelled “non-drowsy” can occasionally make people sleepy. Alcohol can increase that effect.
If tiredness began after starting a medicine or changing its dose, ask a pharmacist or prescriber about it. Don’t stop prescribed treatment yourself; there may be alternatives or adjustments worth discussing.
Some medicines can also affect nutrient levels. Metformin and proton pump inhibitors, used to reduce stomach acid, can contribute to B12 deficiency. That doesn’t mean everyone taking them needs a supplement, but it’s relevant information when investigating unexplained fatigue.
And be honest about your head as well as your body. Stress and depression can contribute to exhaustion. If you’re also losing interest in things, feeling persistently low or struggling to cope, mention that alongside the physical symptoms. You don’t need to choose one explanation before asking for help.
3. Separate a Genuine Need From an Expensive Guess
A deficiency is a reason to investigate and treat. Being tired isn’t proof that you have one.
B12 illustrates the difference. People following vegan diets may need fortified foods or supplements, while absorption problems can cause deficiency even in people who eat animal products. The cause affects treatment, so buying the strongest bottle isn’t necessarily the answer.
As for taking extra when you already have enough, the US National Institutes of Health reports no apparent benefit for athletic performance or endurance in people with adequate B12 status. “Supports energy metabolism” doesn’t mean “will make you feel like a new man”.
Iron deserves similar care. Iron deficiency anaemia can cause fatigue, but replacing iron is only part of the job. A clinician also needs to consider why you’re deficient, including possible blood loss from the digestive tract. Guessing could delay that investigation.
Vitamin D is a separate issue. UK advice is to consider 10 micrograms daily during autumn and winter, with year-round supplementation appropriate for some groups. Following that advice doesn’t establish vitamin D deficiency as the cause of your exhaustion.
Then there’s testosterone, which the internet appears to believe is responsible for every disappointing afternoon. Low testosterone can involve reduced energy, but tiredness alone isn’t enough to diagnose it. Symptoms such as reduced sex drive or fewer spontaneous erections give the conversation more context.
The Endocrine Society advises that diagnosis requires compatible symptoms and consistently low testosterone, confirmed with at least two early-morning blood tests. An advert and a miserable Tuesday don’t meet those criteria.
Be equally sceptical of “adrenal fatigue” products. The Endocrine Society says there’s no scientific proof supporting adrenal fatigue as a medical condition. Adrenal insufficiency is a genuine, different condition requiring medical assessment. Similar words don’t make the supplement pitch legitimate.
4. Get More From the GP Appointment
Book an appointment if unexplained tiredness has lasted a few weeks or is affecting daily life. You don’t have to complete a course of self-improvement first.
Bring your symptom notes and a list of medicines and supplements, including doses. Depending on your history and examination, investigations might include a full blood count, ferritin to assess iron stores, thyroid function and blood sugar. B12, folate or other tests may be appropriate when symptoms or risk factors suggest them.
This is about choosing useful tests, rather than ordering every number available and hoping one explains everything.
There’s also a practical reason to mention supplements before testing. NICE advises taking diagnostic blood samples before starting B12 replacement: supplements can raise measured B12 without fully treating a deficiency. High biotin intake, sometimes found in hair supplements, can distort thyroid test results too. Tell the clinician what you take and follow their instructions; don’t delay prescribed treatment yourself.
If initial results don’t explain things and you’re still struggling, arrange follow-up. Normal blood tests don’t make the exhaustion imaginary, and they don’t exclude problems such as sleep apnoea.
The aim is to find something you can act on. That’s a better purchase than another month’s supply of hope in capsule form.