Always tired? The 10 most common causes of chronic tiredness and what actually helps

In 30 seconds: being tired all the time is not a diagnosis, it is a symptom. In most cases the causes are ordinary and they pile up: short or poor-quality sleep, too little movement, unbalanced meals, too much coffee, stress, a few extra kilos. In some cases, though, there is a medical cause (anaemia, thyroid problems, sleep apnoea, depression, medication) that no habit and no supplement can fix. So the rule is simple: if the tiredness lasts more than 2-3 weeks with no obvious reason, see your doctor and get blood tests first, then think about everything else.

I'm Alfio Nicolosi, an independent FitLine Team Partner: I earn a commission on purchases made through my links, and since this article also talks about supplements, you should know that from the start. I am not a doctor. What I can share is the experience of someone who was tired for years: when I weighed 30 kg more than I do now, I was running on empty by mid-afternoon and blamed it on "a busy patch". It wasn't a busy patch. It was my weight, my sleep and a life spent sitting down.

A note on the wording: in this article "chronic tiredness" means tiredness that has lasted for weeks. Chronic fatigue syndrome (ME/CFS) is a specific illness with precise diagnostic criteria, and it needs specialist care. If you recognise yourself in a disabling exhaustion that gets worse after any effort, however small, talk to your doctor.

First things first: when to see a doctor

See your doctor without waiting if the tiredness:

• has lasted more than 2-3 weeks and has no obvious explanation (a house move, a newborn, an exceptionally heavy period at work);
• comes with shortness of breath, palpitations, pale skin or dizziness;
• arrives together with unintended weight loss or weight gain, intense thirst or feeling cold all the time;
• comes with low mood, loss of interest in things or dark thoughts;
• makes you fall asleep during the day, or the person who shares your bed notices that you snore loudly and stop breathing.

The tests a doctor usually orders as a first round: full blood count, ferritin, TSH, blood glucose, vitamin B12, folate, vitamin D, liver and kidney function. They are inexpensive and they answer the most important question: is there a deficiency or an illness that needs treating, yes or no? Without that answer, any remedy is a shot in the dark.

The 10 most common causes

1. You sleep too little, or badly

This is cause number one, and the most underestimated, because "I've always got by on 6 hours". Most adults need 7-9 hours. Regular timing and quality count too: alcohol in the evening, screens until the last minute and a warm bedroom all reduce deep sleep, even when the number of hours looks right.

What to do: get up at the same time every day, weekends included. Keep the bedroom dark and cool. No caffeine after 2 pm. I go into detail in how to sleep better.

2. Sleep apnoea

If you snore loudly, wake up with a dry mouth or a headache and nod off on the sofa at 9 pm, the problem may not be how many hours you sleep but how you breathe while you sleep. Apnoea is far more common in people who are overweight, and it does not sort itself out: you need a medical assessment and, if your doctor thinks it is appropriate, a sleep study (polysomnography).

3. You don't move enough

It sounds like a paradox, but it is true: the less you move, the more tired you are. A sedentary life reduces the body's capacity to produce energy, and every effort costs more.

What to do: you don't need a gym. You need 30 minutes of brisk walking on most days. It was the foundation of my own journey, and I felt the difference in my energy long before I saw it on the scales. The numbers are here: walking for weight loss, how many steps you need.

4. Meals that make you crash

A pastry and a cappuccino for breakfast, a plate of pasta and nothing else for lunch: lots of sugar, little protein, little fibre. Blood sugar goes up and then comes down, and your concentration goes with it. The 3 pm slump is often sitting on your 1 pm plate.

What to do: protein at every meal, vegetables always, carbohydrates in normal portions and wholegrain where possible. There is a practical example in the high-protein diet meal plan.

5. You eat too little

The other side of the coin: crash diets of 1,000 kcal, skipped meals, improvised fasting. An overly aggressive deficit is paid for in tiredness, feeling cold, irritability and stress eating. If you are dieting and permanently exhausted, you are probably cutting too much. A sustainable pace is 0.5-1 kg a week: losing 10 kg with a realistic plan.

6. You don't drink enough

Even mild dehydration affects concentration and how tired you feel. No formulas needed: a glass of water when you wake up, one with every meal, a bottle on your desk. If your urine is dark, you are not drinking enough.

7. Too much coffee (or coffee at the wrong time)

Caffeine does not give you energy: it masks tiredness for a few hours. When the effect wears off, the tiredness comes back with interest, and a coffee at 5 pm steals deep sleep from the night ahead. The result: the next day you need more. EFSA considers up to 400 mg of caffeine a day (roughly 4-5 espressos) safe for a healthy adult, and 200 mg during pregnancy.

What to do: 2-3 coffees at most, the last one by early afternoon. And count every source: tea, cola, energy drinks, and any supplements that contain caffeine.

8. Stress and mood

Prolonged stress wears you down: muscle tension, light sleep, a mind that never switches off. Tiredness is also one of the most common symptoms of depression, which is not sadness and is not weakness. If, on top of being tired, you no longer feel like doing anything, your doctor is the right person to talk to, and there is nothing to be ashamed of.

9. Extra weight

Carrying 20-30 kg of extra weight means making the same effort, every single day, as someone walking with a full rucksack, while sleeping worse and breathing worse. I say this from first-hand experience: energy was the first real "reward" of losing weight, before the clothes and before the compliments.

10. A medical cause

These are less common than the causes above, but they are the ones you cannot fix on your own:

• Anaemia and iron deficiency, very common in women with heavy periods.
• Hypothyroidism: tiredness, feeling cold, dry skin, weight gain.
• Diabetes or prediabetes: tiredness, thirst, needing to urinate often.
• Vitamin B12 or folate deficiency, more common in people on a vegan diet who don't supplement and in people taking certain medicines.
• Vitamin D deficiency, widespread in winter and in people who spend little time outdoors.
• Medication: antihistamines, some blood pressure medicines, anti-anxiety drugs, antidepressants. If the tiredness started with a new treatment, tell your doctor. Do not stop anything on your own initiative.
• After a viral infection, tiredness can last for weeks.

Vitamins and minerals: what they can really do

There is a lot of confusion here, so I'll start with the law. In Europe, a supplement may state that it "contributes to the reduction of tiredness and fatigue" only if it contains a significant amount of one of these nutrients: vitamin C, vitamins B2, B3 (niacin), B5, B6, B12, folate, magnesium, iron. These are claims authorised following EFSA's assessment.

Put honestly:

• If you have a deficiency (iron, B12, vitamin D), correcting it makes an enormous difference. But a deficiency is found through blood tests and treated with your doctor: iron, for example, should not be taken "just to try it", because too much does harm.
• If your diet is low in fruit, vegetables and wholegrains, a vitamin and mineral supplement covers part of what is missing. It is a help, not a solution.
• If you sleep 5 hours, don't move and drink 6 coffees, no sachet will make up for it. Supplements work on your nutrient needs, not on your habits.

Do not exceed the daily amounts stated on the label. Food supplements should not be used as a substitute for a varied, balanced diet and a healthy lifestyle.

The FitLine products I use, and what they are really for

I'll list them with what is written on the label, and no extra promises:

• PowerCocktail, in the morning: vitamin C and the whole B group (B2, B6, B12, niacin, pantothenic acid, folic acid), which contribute to the reduction of tiredness and fatigue and to normal energy-yielding metabolism, plus fibre and live cultures. It contains 30 mg of caffeine from guarana. The full guide is here: PowerCocktail: what it is for and how to take it. If you don't want caffeine, there is Basics.
• Restorate, in the evening: minerals, including magnesium and iron (which contribute to the reduction of tiredness and fatigue), calcium, zinc and vitamin D. It is not a sleeping aid and it does not "make you sleep": it is a mineral supplement that I choose to take at the end of the day. Tolerability and warnings are covered in Restorate: side effects and how to use it.
• Activize Oxyplus, when needed: B vitamins and caffeine from guarana. What I wrote about coffee applies here too: caffeine masks tiredness, it does not resolve it, and it counts towards your total for the day. Details in Activize Oxyplus: what it is and how to use it.

In my case, the energy came back with the weight I lost, the walking and the regular sleep. I think of supplements as the final 10%, not the first 90%. If you take medication or have a medical condition, ask your doctor before adding any supplement: the interactions worth knowing about are in the article on FitLine side effects and product safety.

A 14-day plan to find out where your tiredness comes from

This is not a treatment: it is a way to clear the ordinary causes out of the way and see whether anything is left to investigate.

1. Sleep: same alarm every day, in bed early enough for 7-8 hours, phone out of the bedroom.
2. Coffee: 2-3 at most, the last one by 2 pm.
3. Movement: 30 minutes of brisk walking, split in two if that is easier.
4. Meals: protein and vegetables at lunch and dinner, and a breakfast that is not only sweet.
5. Water: a glass when you wake up and with every meal, a bottle within reach.
6. Alcohol: none for two weeks. It is the most revealing test for your sleep.
7. Diary: every evening, score the day's energy from 1 to 10.

If your average score has gone up after 14 days, you have found your causes. If nothing has changed, you have an even more useful piece of information: take the diary to your doctor and ask for the tests.

Frequently asked questions

Which vitamins help with tiredness? The ones with an authorised claim on the reduction of tiredness and fatigue are vitamin C, B2, niacin, B5, B6, B12 and folate, along with magnesium and iron. They help if your intake is too low: they do not give "extra energy" to someone who already gets enough.

Does magnesium work for tiredness? Magnesium contributes to the reduction of tiredness and fatigue and to normal muscle function. If you get little of it from your diet (few leafy greens, few pulses, nuts or wholegrains), it may help. It is not a stimulant and it does not have an immediate effect.

Why am I tired even though I sleep 8 hours? The most common possibilities: poor-quality sleep (alcohol, apnoea, a warm room, waking in the night), a sedentary life, a deficiency (iron, B12, vitamin D), thyroid problems, mood. This is exactly the situation where blood tests make sense.

How long does it take to see results from changing habits? For sleep and coffee, a few days are enough. For movement, 2-3 weeks. If there is a deficiency to correct, the timescale is set by your doctor on the basis of your tests.

Is coffee good or bad for you? In moderate amounts and in the first part of the day, it is absolutely fine. It becomes a problem when it is used to cover up too little sleep, because it feeds the vicious circle.

Can supplements replace blood tests? No. Taking vitamins "to see if it goes away" can delay the discovery of anaemia or a thyroid problem. First you understand the cause, then you decide what to do.

Conclusion

Tiredness that won't go away almost never has a single cause: usually it is the sum of sleep, movement, what is on your plate, coffee and stress, and sometimes there is an underlying medical problem that has to be found with tests. Start there. Vitamins and minerals have a precise and limited role, the one the law allows them to state: contributing to the reduction of tiredness when your intake falls short. Everything else is down to habits, and that is good news, because habits are up to you.

Read also:

• Best supplements for energy and concentration
• Slow metabolism: what is actually true
• Magnesium and potassium: what they are for

FitLine is a registered trademark of PM-International AG. This site is run by an independent Team Partner and is not the company's official website. The information is for educational purposes and does not replace medical advice.