Müdigkeit

Always Tired? The Most Common Causes — and What’s Really Behind It

19. August 2026 12 min Lesezeit
Medizinisch geprüft von Christian Lazar
Man stands at the kitchen window in the morning with a cup of coffee, looking out thoughtfully

Man stands at the kitchen window in the morning with a cup of coffee, looking out thoughtfully

Medizinisch geprüft Quellenangaben am Ende Aktualisiert August 2026
Das Wichtigste auf einen Blick
  • Müdigkeit über mehr als vier Wochen gehört ärztlich abgeklärt — Eisenmangel, Schilddrüsenunterfunktion, B12-Mangel und Schlafapnoe sind häufig und gut behandelbar.
  • Neun Nährstoffe tragen laut EU-Unionsliste zur Verringerung von Müdigkeit und Ermüdung bei: Eisen, Magnesium, Vitamin C sowie B2, B3, B5, B6, B12 und Folat.
  • Die größten Alltagshebel sind Schlafqualität, Eiweiß zu jeder Mahlzeit, Tageslicht am Vormittag, tägliches Gehen und kein Koffein nach 14 Uhr.
  • Für Shilajit, Ginseng und Ashwagandha gibt es in der EU keine zugelassene gesundheitsbezogene Angabe — sie lassen sich nur sachlich beschreiben.

You get your seven hours of sleep, you don’t do anything differently than usual — and still you drag yourself through the day. In the afternoon your concentration drops, and by evening there’s nothing left. If that’s not just a single bad day, but the norm, it’s worth asking: what’s actually causing it?

The honest answer is: there is no single cause. Fatigue is a collective term for a wide range of conditions, some of which are harmless and others that require medical attention. This text puts them in order — from the causes you cannot resolve yourself, to everyday habits, to the nutrients for which a connection can actually be demonstrated.

Müde, exhausted, or drained — those are three different things

The terms are being mixed up, but they do not mean the same thing:

  • Fatigue is the normal urge to sleep. It comes in the evening, it comes after a short night, and it disappears when you sleep. That is not a problem, but a signal that is working properly.
  • Exhaustion persists even after sleep. You wake up and don’t feel rested. That’s the state most people mean when they say: I’m constantly tired.
  • Lack of drive is something different — the issue here is not a lack of strength, but a lack of drive. Anyone who is physically able, but doesn't get started, should take this seriously: it can be a sign of a depressive episode and should then be professionally assessed.

This distinction is more than mere semantics. It leads to very different next steps.

First things first: When fatigue needs medical attention

We are deliberately placing this section at the front, even though it reads less smoothly than everyday tips. Persistent fatigue is one of the most common symptoms overall — and one of the least specific. It can be caused by medical conditions that can be treated well if they are identified.

Go to the doctor if the fatigue lasts longer than four weeks, if it occurred without any apparent reason, if it gets worse, or if one of these signs is added:

  • unintended weight loss or unintended weight gain
  • Shortness of breath during exertion that used to be no problem
  • noticeable paleness, brittle nails, hair loss
  • loud snoring with pauses in breathing, morning headaches
  • Fever, night sweats, or swollen lymph nodes
  • strong thirst and frequent urination
  • depressed mood, loss of interest, brooding for weeks

The most common medical causes that a blood test or a consultation can clarify:

Possible cause Typically included How to find it
Iron deficiency Paleness, shortness of breath, brittle nails; common with heavy menstruation, during pregnancy, with a purely plant-based diet Ferritin in the blood, assessed together with CRP
Hypothyroidism Cold intolerance, weight gain, dry skin, slow pulse TSH, if necessary fT3 and fT4
Vitamin B12 deficiency Tingling in the hands and feet, difficulty concentrating; especially with a vegan diet, from age 60, and when taking acid blockers Holo-transcobalamin or methylmalonic acid — more meaningful than the total value
Sleep apnea loud snoring with pauses in breathing, daytime microsleeps, morning headache Consultation, then sleep lab
Diabetes Thirst, frequent urination, vision problems Fasting blood sugar, HbA1c
Depression depressed mood, loss of interest, sleep disturbances for more than two weeks medical or therapeutic consultation
Medication Started at a time consistent with the new medication — such as beta-blockers, antihistamines, some blood pressure medications Consult your doctor or pharmacist

No dietary supplement can replace this assessment. Anyone who takes supplements for months while an underactive thyroid is present in the background is losing time.

The everyday causes that are within your control

If the assessment remains inconclusive — and that is the most common outcome —, it is worth looking at six key levers. None of them is spectacular. Together, experience shows, they make the biggest difference.

1. Sleep: it's not just the duration that matters

Seven hours in bed are not seven hours of sleep. Anyone who wakes up several times during the night, eats late, drinks alcohol, or lies in a room that is too warm goes through fewer complete sleep cycles — and wakes up feeling unrested, even though the clock says otherwise. How sleep actually works, which phases there are, and what sleep hygiene specifically means is explained in our comprehensive sleep guide.

2. The Blood Sugar Roller Coaster

A breakfast of white bread and jam, pasta at lunchtime, and something sweet in the afternoon: Each time, blood sugar rises quickly and then drops just as fast afterward. Many people know this afternoon slump around 2 or 3 p.m. — it is not fate, but a consequence of the composition of the meals. Protein, fiber, and fat with every meal flatten the curve. The effect usually becomes noticeable within just a few days.

3. Not enough liquid

Already a mild lack of fluids shows up as reduced concentration and a feeling of pressure in the head, long before you feel thirsty. One and a half to two liters over the course of the day is a good general guideline for most adults, with more needed in hot weather and during exercise. The simplest test: drink a glass of water and see whether the afternoon slump is less noticeable after twenty minutes.

Too little exercise — not too much

That sounds contradictory, but it has been well researched: people who move very little feel more tired, not more rested. The body loses fitness, and even everyday demands become more exhausting. This is not about sport in the sense of training — twenty to thirty minutes of brisk walking a day, ideally outdoors, are the best place to start in terms of effort versus benefit.

5. Light — especially from October to March

The internal body clock needs bright light in the morning to stabilize the day-night rhythm. In winter, many people indoors don’t get enough of it: an office may have 500 lux, while an overcast winter day outside still has several thousand. Twenty minutes outdoors in the morning has more effect at this level than any capsule.

6. Caffeine at the wrong time

Caffeine has a half-life of about five hours — the espresso at 4 p.m. is still half effective at 9 p.m. Anyone who has trouble falling asleep and needs caffeine in the morning to wake up can quickly get stuck in a self-perpetuating cycle. The simplest rule: no more caffeine after 2 p.m., and stick to it consistently for two weeks.

Mann lehnt sich am Nachmittag am Schreibtisch zurück und blickt aus dem Fenster ins Grüne
The afternoon slump around 2 p.m. usually has two causes — and both can be changed.

The nine nutrients that help fight fatigue

At this point, a lot is claimed on the internet. One manageable group can be verified: Exactly nine nutrients help reduce tiredness and fatigue — and the list is shorter than advertising would lead you to believe:

Nutrient Where it typically gets tight
Iron strong menstruation, pregnancy, purely plant-based diet, blood donation
Magnesium high sweat loss due to exercise, an unbalanced diet, some diuretics
Vitamin C little fruit and vegetables, smoking
Vitamin B2 (Riboflavin) few dairy products, a purely plant-based diet
Vitamin B3 (Niacin) unbalanced diet, regular alcohol consumption
Vitamin B5 (Pantothenic acid) Highly processed food
Vitamin B6 regular alcohol consumption, certain medications
Vitamin B12 vegan diet, from age 60, acid blockers, Metformin
Folate little green vegetables, pregnancy, alcohol consumption

A second connection runs through the normal energy metabolism: Involved in this are vitamins B1, B2, B3, B5, B6, B7, B12, and C, as well as magnesium, iron, copper, iodine, manganese, phosphorus, and calcium — the group is significantly larger.

One point that is often misunderstood: These nutrients are needed for a normally functioning process. If you are getting enough, having more of them will not make you more alert. The benefit lies in closing a gap — not in boosting beyond the normal state.

The three gaps that occur most frequently in Germany

Iron. The most common nutrient deficiency by far, especially among women of childbearing age. Iron contributes to reducing tiredness and fatigue, as well as to the normal formation of red blood cells and hemoglobin. Important: Iron should only be supplemented in cases of a confirmed deficiency — the body has no active way of getting rid of excess amounts. The level is called ferritin. Anyone supplementing should take it on an empty stomach and with a glass of orange juice, because Vitamin C increases iron absorption; coffee, tea, and calcium significantly inhibit it.

Vitamin B12. Comes in significant amounts almost exclusively in animal-based foods. With a purely plant-based diet, supplementation is necessary from a nutritional science perspective, not optional. A B12 deficiency develops gradually over years because the liver stores a reserve — and is often only noticed once the nerves are affected. Our page on the individual B vitamins explains all eight B vitamins in detail B vitamins.

Vitamin D. Trägt zwar nicht zur Verringerung von Müdigkeit bei — there is no such claim for vitamin D —, but it does contribute to the normal function of the immune system and the maintenance of normal muscle function. Between October and March, the sun is too low in the sky in Germany for the body to produce it in the skin. Anyone who wants to know their level can have their 25-OH vitamin D measured.

Frühstückstisch mit Rührei, Vollkornbrot, Nüssen und Beeren in hellem Tageslicht
Protein and fiber at every meal flatten the blood sugar curve.

Does magnesium, ashwagandha, or zinc make you tired?

A question we’re often asked — and one that deserves a nuanced answer.

Magnesium does not make you sleepy in the sense of a sleeping aid. What can be said is this: It contributes to reducing tiredness and fatigue, to the normal function of the nervous system, to normal muscle function, and to normal psychological function. The fact that many people find it pleasant in the evening is probably related to muscle function — a sleep-inducing effect has not been proven. If it makes you sluggish in the morning, you should rather check the dose: Larger amounts taken at once can put strain on the gastrointestinal tract, and that costs energy. Which form is suitable for what can be found on our page about Magnesium.

Ashwagandha is a traditional plant in Ayurvedic teaching. The root is used as a standardized extract — the withanolide content is the key figure by which products can be compared. More about its origin and extraction can be found in our Ashwagandha products.

Zinc plays no role in fatigue. Its contribution lies elsewhere: in the immune system, cognitive function, protecting cells from oxidative stress, and acid-base metabolism. Anyone who feels nauseous after taking it probably took it on an empty stomach — zinc should be taken with a meal.

What is traditionally used

Besides the nutrients, there is a second group: plant-based and mineral substances from ancient traditions. What they are and where they come from:

Shilajit is a resin that forms over very long periods in rock crevices of the Himalayas and seeps from the rock there in summer. In the Ayurvedic tradition, it bears the name Shilajit and has been used for centuries. Chemically, it is known for its content of fulvic acid and humic substances as well as minerals and trace elements. We use the standardized branded raw material PrimaVie®, for which the manufacturer provides its own studies. About origin, extraction, composition, dosage, and safety, we have a Detailed Shilajit Guide written — it also states there who should not take Shilajit. You can find the product here: Shilajit Capsules.

Panax Ginseng originates from the East Asian tradition; the root extract is standardized for its ginsenoside content — the key figure used to compare extracts. Cordyceps is a medicinal mushroom that was traditionally harvested in the highlands of Tibet and is now cultivated.

A realistic plan for the next two weeks

Whoever changes everything at once rarely sticks with it and, in the end, doesn’t know what actually made a difference. So here’s a suggestion in the order in which you’re most likely to notice results:

Week What you change How you can tell
In advance Appointment with your GP if the fatigue lasts longer than four weeks. Ask about a blood test including ferritin, TSH, and B12. You know whether there is a treatable cause behind it
Week 1 No caffeine after 2 pm. Twenty minutes outside every morning. A source of protein with every meal. The afternoon slump becomes milder, falling asleep easier
Week 2 A regular bedtime, even at weekends. Twenty to thirty minutes of brisk walking every day. Drink one and a half to two litres. Morning, getting up is easier
Afterwards First think about supplements now — and then target them based on blood values, not on speculation. You add what is missing instead of guessing

This order is no coincidence. The first two weeks cost nothing and have a more noticeable effect for most people than any supplement. And they create the foundation on which targeted supplementation can achieve anything at all.

Mann geht am Vormittag zügig einen Weg entlang, der durch grüne Bäume führt
Twenty minutes outdoors in the morning has a greater effect on your internal clock than any capsule.

Briefly summarized

  • Mildness, exhaustion, and listlessness are three different conditions with different next steps.
  • If fatigue lasts longer than four weeks or warning signs appear, it should be evaluated by a doctor — iron deficiency, thyroid issues, B12 deficiency, and sleep apnea are common and treatable.
  • The biggest levers in daily life are sleep quality, meal composition, daylight in the morning, exercise, and caffeine timing.
  • Nine nutrients help reduce tiredness and fatigue: iron, magnesium, vitamin C, as well as B2, B3, B5, B6, B12, and folate. They fill gaps — they do not boost energy.
  • At the same extract potency, such as Shilajit, ginseng, or cordyceps, standardization to the key active compound determines whether two products can be compared.

Food supplements are not a substitute for a varied diet or a healthy lifestyle. If symptoms persist, the cause should be medically examined.

Quellenangaben & Studien
Verordnung (EU) Nr. 432/2012 der Kommission: Liste zulässiger gesundheitsbezogener Angaben — darunter „trägt zur Verringerung von Müdigkeit und Ermüdung bei“ für Eisen, Magnesium, Vitamin C, B2, B3, B5, B6, B12 und Folat.
Verordnung (EG) Nr. 1924/2006 (HCVO): Grundregeln für nährwert- und gesundheitsbezogene Angaben über Lebensmittel.
EU-Register der Health Claims, Stand 2026: Botanicals wie Shilajit, Ginseng, Ashwagandha und Cordyceps sind als „on hold“ geführt, ohne zugelassene Angabe.
Deutsche Gesellschaft für Ernährung: Referenzwerte für die Nährstoffzufuhr.
Robert Lazar
Über den Autor

Robert Lazar

Gründer & Geschäftsführer · 10+ Jahre Produktentwicklung

Robert Lazar beschäftigt sich seit über zehn Jahren intensiv mit Mikronährstoffen, pflanzenbasierten Wirkstoffen und ganzheitlicher Gesundheitsoptimierung. Er verbindet ernährungswissenschaftliches Wissen mit der täglichen Arbeit in der eigenen Manufaktur in Memmingen.

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Christian Lazar
Medizinisch geprüft von
Christian Lazar
Approbierter Apotheker · Gründer & Geschäftsführer

„Dieser Artikel wurde vor Veröffentlichung auf wissenschaftliche Korrektheit und pharmazeutische Genauigkeit geprüft."— Geprüft am 18. August 2026

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