Feeling tired all the time (TATT) is common enough that doctors use the acronym in their notes, and tiredness is one of the most common reasons people make an appointment. Tiredness that carries on for weeks and doesn’t lift with rest is worth looking into, and it often has more than one contributing factor.
Sleep and stress are the causes most people think of first, while diet is easier to overlook. Low levels of certain nutrients are recognised causes of tiredness, and regular meals and activity both influence how steady energy feels through the day. Working out what sits behind persistent tiredness comes first, before any change to diet or food supplements.
Why Am I Always Tired? Common Causes of Tiredness and Low Energy
Feeling tired all the time is usually linked to lifestyle factors such as sleep, alcohol, and activity levels, psychological factors such as stress and low mood, or physical causes including iron deficiency anaemia, thyroid problems, and some vitamin deficiencies. Tiredness that persists without a clear reason should be assessed by a doctor.
Short or irregular sleep, too little or too much physical activity, long hours or changing shifts, and eating or drinking too little may leave people feeling less alert.
Worry can make it hard to switch off at night, and stress, anxiety, low mood, and bereavement can leave people exhausted for some time. Tiredness can also make stress harder to cope with, so each can make the other worse.
Hormonal changes during pregnancy and around the menopause often bring tiredness with them. Several medical conditions can cause ongoing tiredness, including sleep apnoea, an underactive or overactive thyroid, diabetes, heart conditions, and myalgic encephalomyelitis or chronic fatigue syndrome (ME/CFS), and some medicines list tiredness as a side effect. If any of these may be involved, identifying the underlying cause with a doctor comes before thinking about nutritional support.
Why Am I Tired Even After Sleeping?
A full night in bed does not always mean restful sleep. Alcohol, caffeine later in the day, and screens before bed can disrupt sleep, and loud snoring with gasping or choking noises can be a sign of sleep apnoea. Low levels of iron, vitamin B12, or folate may also leave people tired despite getting enough sleep, and a blood test can check for these.
When to Speak to a Doctor About Tiredness
The following should be checked by a doctor:
- tiredness lasting a few weeks without a clear reason
- tiredness that affects daily life, work, or relationships
- unexplained weight loss
- night sweats, fever, or swollen glands
- shortness of breath, noticeable heartbeats (palpitations), or paler than usual skin
- feeling very thirsty or needing to urinate more often, particularly at night
- loud snoring with gasping or choking noises during sleep
- changes in mood alongside tiredness
Unusual bleeding or bruising, problems swallowing, or changes in bowel habits that do not get better should be checked promptly. A doctor may arrange blood tests to look for anaemia, thyroid problems, diabetes, and low vitamin levels. Keeping a simple diary of sleep, meals, and energy levels for a couple of weeks beforehand can help show patterns.
Everyday Habits That Affect Energy
The NHS links many cases of tiredness to stress, not enough sleep, poor diet, and other lifestyle factors, and suggests self-help steps.
Keep Sleep Times Regular
Aiming for six to nine hours of sleep, and going to bed and getting up at the same time each day, are both part of NHS advice. A sleeping area that is not too bright, noisy, or warm helps, as does avoiding screens in the final hour before bed. Daytime naps can make it harder to sleep well at night.
Eat Regular, Balanced Meals
Eating regular meals and healthy snacks every three to four hours is one way the NHS suggests keeping energy up through the day, and the Eatwell Guide sets out a balanced pattern to follow. Ensure the diet includes a protein source, such as eggs, fish, beans, lentils, or meat, at every meal. Meals built mostly around sugary foods and white, low-fibre starches may be followed by a dip in energy for some people, while meals that combine protein with fibre-rich carbohydrates tend to be digested more gradually. Very restrictive diets, or cutting out whole food groups, need some planning so that nutrients such as iron and vitamin B12 are still covered.
Drink Enough Fluid
Six to eight glasses of fluid a day is the NHS guide, with more needed in hot weather, during illness, or when active for long periods. Water, lower-fat milk, and sugar-free drinks, including tea and coffee, all count. Feeling tired is one of the recognised signs of dehydration.
Keep Caffeine and Alcohol in Check
Caffeine can make people feel more alert in the short term, but it can also disrupt normal sleep rhythms and lead to daytime tiredness. Keeping tea, coffee, cola, and energy drinks to earlier in the day, or switching to decaffeinated versions later on, may help. Alcohol can interfere with sleep too, and the NHS advises drinking no more than 14 units a week, spread over three or more days.
Build Activity Up Gradually
Regular exercise can leave people feeling less tired over time, according to the NHS, even though it is hard to start when energy is low. Adults are advised to do at least 150 minutes of moderate activity or 75 minutes of vigorous activity a week, with strengthening activities on at least two days. Short walks are a reasonable starting point. Too much activity without enough rest can affect energy levels, and exercise in the couple of hours before bed can make sleep harder.
Allow Time to Rest and Unwind
Stress can’t always be avoided, and busy periods come and go. Short breaks during the day, time outdoors, and a regular wind-down in the evening are realistic places to start. For low mood or anxiety that continues, NHS talking therapies can be accessed through a doctor or by self-referral.
Nutrient Deficiencies Linked to Tiredness
Tiredness is a recognised symptom of several nutrient deficiencies, and checking for them is a routine part of investigating persistent tiredness. The deficiencies most often looked for are:
- Iron deficiency anaemia, which can cause tiredness and lack of energy, shortness of breath, noticeable heartbeats, headaches, and paler than usual skin. It is the most common type of anaemia, according to the NHS.
- Vitamin B12 or folate deficiency anaemia, which can cause feeling weak or tired, shortness of breath, and a sore or red tongue, sometimes with mouth ulcers. Low vitamin B12 can also cause pins and needles and muscle weakness.
- Low vitamin D, which a 2025 UK Government survey found in nearly one in five adults aged 19 to 65, according to the British Heart Foundation. Symptoms tend to be vague but can include tiredness and low energy.
The NHS also lists less common signs of iron deficiency anaemia, including hair loss and nail changes such as spoon-shaped nails, so changes to hair and nails should also be mentioned to a doctor alongside tiredness.
Some people are more likely to have low levels than others. Heavy periods and pregnancy increase the risk of iron deficiency. Vitamin B12 is not found naturally in fruit, vegetables, or grains, so anyone following a vegan diet without fortified foods or a supplement may not get enough. In the UK, the most common cause of vitamin B12 deficiency is pernicious anaemia, an autoimmune condition that stops the body from absorbing vitamin B12 from food. Some long-term medicines can affect how certain nutrients are absorbed, and a pharmacist or doctor can advise on this.
The symptoms of these deficiencies overlap with many other causes of tiredness, so a blood test is needed to confirm one. Low iron in particular needs its cause identified, as it can result from blood loss, and any diagnosed deficiency is treated under a doctor’s advice.
Vitamins and Minerals That Contribute to the Reduction of Tiredness and Fatigue
UK health claims about nutrients can only use wording that regulators have reviewed and approved, which is held on a public list called the GB Nutrition and Health Claims Register. It is the claims, not the nutrients themselves, that are authorised. The vitamins and minerals below each hold authorised claims relating to tiredness and fatigue or to energy-yielding metabolism. They are not a treatment for tiredness or for any condition that causes it, and food supplements should not be used as a substitute for a varied and balanced diet and a healthy lifestyle. Vitamin D holds no authorised claim relating to tiredness, even though low levels are common in the UK.
The body releases usable energy from food through a series of chemical reactions known as energy-yielding metabolism, and many vitamins and minerals help individual steps take place.
Iron and Vitamin C
Iron is needed to make haemoglobin, the protein in red blood cells that carries oxygen around the body. Iron contributes to the reduction of tiredness and fatigue. Iron contributes to normal oxygen transport in the body.
NHS guidance is 8.7mg of iron a day for men aged 19 and over and women aged 50 and over, and 14.8mg for women aged 19 to 49. Women who still have periods after the age of 50 may need the same amount as younger women. Most people can get the iron they need from a varied and balanced diet. The NHS advises that taking 17mg or less a day of iron supplements is unlikely to cause harm, and anyone advised by a doctor to take a higher dose should continue to do so. Higher doses can cause side effects such as constipation, stomach pain, and feeling sick.
Vitamin C increases iron absorption, so plant sources of iron such as beans or fortified cereals can be eaten alongside a vitamin C-rich food such as peppers or oranges. Vitamin C contributes to the reduction of tiredness and fatigue. For adults aged 19 to 64, the NHS recommends 40mg of vitamin C a day.
Good sources of iron include red meat, beans such as kidney beans and chickpeas, nuts, dried fruit such as dried apricots, and fortified breakfast cereals, although the Department of Health and Social Care advises limiting red and processed meat. Vitamin C is found in citrus fruit, peppers, strawberries, blackcurrants, broccoli, Brussels sprouts, and potatoes.
Vitamin B12 and Folate
Vitamin B12 and folate are both needed to produce healthy red blood cells, and a shortfall in either can lead to the same type of anaemia. Vitamin B12 is also needed to help the body use folate.
Vitamin B12 contributes to the reduction of tiredness and fatigue. Vitamin B12 contributes to normal red blood cell formation. Adults aged 19 to 64 need about 1.5 micrograms of vitamin B12 a day, and people who eat meat, fish, or dairy foods can usually get enough from their diet.
Folate contributes to the reduction of tiredness and fatigue. Folate contributes to normal blood formation. Adults need 200 micrograms of folate a day. Folic acid is the manmade form of folate, and the NHS advises anyone who is pregnant, trying for a baby, or could become pregnant to take a 400 microgram folic acid supplement daily until 12 weeks of pregnancy.
Vitamin B12 is found in meat, fish, milk, cheese, eggs, and some fortified breakfast cereals. Good sources of folate include broccoli, Brussels sprouts, peas, chickpeas, kidney beans, breakfast cereals fortified with folic acid, and leafy greens such as kale, spring greens, and spinach.
Magnesium
Magnesium is a mineral involved in many processes in the body, including turning food into energy. Magnesium contributes to a reduction of tiredness and fatigue. Magnesium contributes to normal energy-yielding metabolism.
Men aged 19 to 64 need 300mg of magnesium a day and women of the same age need 270mg, according to the NHS. Having 400mg or less a day from supplements is unlikely to cause harm, although higher doses taken for a short time can cause diarrhoea.
Magnesium is found in a wide variety of foods, including spinach, nuts, and wholemeal bread.
Other B Vitamins
Riboflavin (vitamin B2) contributes to the reduction of tiredness and fatigue, and niacin (vitamin B3), pantothenic acid (vitamin B5), and vitamin B6 hold the same authorised claim. Thiamine (vitamin B1) contributes to normal energy-yielding metabolism, as does biotin, although neither holds an authorised claim relating to tiredness.
The B vitamins work together in many metabolic pathways and are often provided together in a balanced B-complex. The NHS advises taking no more than 10mg of vitamin B6 a day in supplements unless a doctor advises otherwise, and notes that taking 200mg or more a day can lead to a loss of feeling in the arms and legs.
Between them, these B vitamins are found in milk, eggs, meat, poultry, fish, mushrooms, oats, wholegrain foods, and fortified breakfast cereals.
Minerals With Roles in Energy-Yielding Metabolism
Five other minerals hold authorised claims for energy-yielding metabolism without holding a claim relating to tiredness. Calcium contributes to normal energy-yielding metabolism, and copper, iodine, manganese, and phosphorus hold the same authorised claim. A varied diet usually provides enough of each.
Dairy foods provide calcium, phosphorus, and iodine. Nuts are a source of copper and manganese, wholegrain cereals provide manganese, and shellfish provide both iodine and copper.
CoQ10, Creatine, and Other Ingredients in Energy Products
Several ingredients appear widely in energy products without holding an authorised claim relating to tiredness or fatigue. The absence of an authorised claim means the evidence has either not been submitted or not been assessed as meeting the specific standard a claim requires, and it reflects that regulatory standard only.
Coenzyme Q10 (CoQ10) is a compound the body makes itself, and small amounts are also obtained from food. Claims for CoQ10, including one relating to energy-yielding metabolism, were assessed by the European Food Safety Authority in 2010 and not authorised, and no authorised health claim for CoQ10 exists on the GB Register.
Creatine does hold an authorised claim, although it relates to exercise and not to tiredness. Creatine increases physical performance in successive bursts of short-term, high-intensity exercise. The claim applies to a daily intake of 3g and to adults performing high-intensity exercise, so its relevance is to training and sport.
Chlorella is a freshwater alga and spirulina is a type of cyanobacterium, often called blue-green algae, and both contain a range of nutrients. Any authorised claims made for products containing them depend on the vitamins and minerals present in sufficient amounts, not on the chlorella or spirulina itself.
Ashwagandha, a herb with a long history of use in Ayurvedic practice, is also common in energy and stress products, and no health claims for it have been authorised on the GB Register.
Choosing and Using a Supplement Sensibly
Where dietary intake is inadequate, addressing this is likely to have a greater impact than relying on any single vitamin or supplement. Tiredness with a medical cause needs that cause identifying first.
When comparing energy supplements, the label is a useful starting point. It lists each nutrient, the amount per daily serving, and the percentage of the nutrient reference value (NRV), a standard daily figure used on food labels. The form of a nutrient can influence how it is absorbed and used by the body, although this varies between nutrients, and some supplements use forms selected for their bioavailability.
Combining products needs some care, since the same nutrient can appear in more than one. The NHS gives upper amounts for iron and vitamin B6 taken as supplements, and advises keeping total vitamin A from food and supplements to no more than 1.5mg a day, so a multivitamin taken alongside a single-nutrient product can push the total higher than expected. Very high doses of iron can be fatal, particularly for children, so iron supplements should always be stored out of their reach.
During pregnancy, the NHS advises avoiding cod liver oil and any supplements containing vitamin A (retinol). Anyone taking prescribed medication, who is pregnant or breastfeeding, or who has an existing health condition should speak to a doctor or pharmacist before starting a new supplement.
Energy and Tiredness Through Every Life Stage
Tiredness is common in pregnancy, particularly in the first 12 weeks, when hormonal changes can play a part. Pregnancy is also one of the most common causes of iron deficiency anaemia, most often because the diet does not provide enough iron. Looking after a new baby brings broken sleep that can take time to recover from.
Around perimenopause and the menopause, tiredness is often reported alongside disrupted sleep, night sweats, and changes in mood, and it is among the symptoms sometimes linked to changes in hormone levels at this stage. The amount of iron women need also falls once periods stop. For men, the same causes of tiredness apply, and tiredness alongside loud snoring, low mood, or weight changes is a reason to see a doctor.
The NHS notes that people aged 65 and over are particularly at risk of malnutrition, and living alone, poorly fitting dentures, or difficulty shopping and cooking can all make eating well harder. Pernicious anaemia is more common in women around the age of 60. Stores of vitamin B12 in the body can last several years, so problems linked to a change in diet may take a long time to appear. The NHS advises anyone who is not often outdoors, including people who are frail, housebound, or living in a care home, to take a daily 10 microgram vitamin D supplement throughout the year.
Persistent tiredness often has more than one cause, and a doctor is the right first step when it lingers or comes with other symptoms. Drawing on more than 30 years of Good Health Naturally’s experience as an independent family business, our nutrition team is available to discuss general nutritional support for anyone who would like to talk it through.
Frequently Asked Questions
What Is My Body Lacking If I Am Always Tired?
Tiredness has many possible causes, and a nutrient shortfall is only one of them. Low iron, vitamin B12, folate, and vitamin D are among the things a doctor may check with a blood test. The symptoms of these deficiencies overlap, so testing gives a clearer answer than guesswork, and it can also rule out other causes that need medical attention.
What Are the Red Flags of Fatigue?
Tiredness that lasts for a few weeks without a clear explanation, or that comes with unexplained weight loss, night sweats, fever, or breathlessness, should be checked by a doctor. Loud snoring with gasping during sleep is another reason to have tiredness looked at.
Why Am I Tired All the Time Even Though I Eat Well?
A healthy diet doesn’t rule out every nutritional cause of tiredness. Needs for some nutrients rise during pregnancy or with heavy periods, and certain conditions and medicines can affect how nutrients are absorbed. Many causes of tiredness have nothing to do with diet, including poor sleep, stress, and thyroid problems, so ongoing tiredness should be discussed with a doctor.
Do Vitamins for Tiredness Really Work?
Iron, vitamin B12, folate, magnesium, vitamin C, and several other B vitamins hold authorised claims relating to the reduction of tiredness and fatigue, which reflects their established roles in the body. Where dietary intake of these nutrients is inadequate, addressing that is likely to make the greatest difference. If tiredness has another cause, such as poor sleep, stress, or a medical condition, a supplement is unlikely to resolve it.
Can Supplements for Tiredness Be Taken Alongside Medication?
Some vitamins and minerals can interact with medicines, and some medicines can affect how nutrients are absorbed. Anyone taking regular medication should check with a doctor or pharmacist before starting a new supplement, and it helps to mention any supplements already being taken at medical appointments.
Does Vitamin D Give You Energy?
Vitamin D does not hold an authorised claim relating to tiredness or energy. Vitamin D contributes to the maintenance of normal muscle function. Vitamin D contributes to the normal function of the immune system. Low vitamin D is common in the UK and its symptoms can be vague, so a doctor may check levels when investigating tiredness. The NHS advises that everyone should consider taking a daily 10 microgram vitamin D supplement during autumn and winter, when the body cannot make enough from sunlight.
