Vitamin D Deficiency Symptoms: Common and Unusual Signs

Quick answer

Often no symptoms; bone pain, muscle weakness and tiredness are the most typical; a blood test confirms it

Vitamin D deficiency is widespread worldwide; an international review estimated that a substantial proportion of people in many countries have low levels, particularly in winter. Most people with mild deficiency have no symptoms. When symptoms occur, the most typical are bone pain or tenderness, muscle aches and weakness (for example, difficulty climbing stairs or getting up from a chair), and tiredness. Severe, long-term deficiency causes rickets in children and osteomalacia (soft bones) in adults. Other associations, such as low mood, frequent infections and hair loss, have been reported, but low vitamin D has not been proven to cause them. A blood test for 25-hydroxyvitamin D confirms deficiency. The NHS advises a daily 10 microgram supplement in autumn and winter for most people, and all year for those at higher risk.

Important. See a doctor if you have persistent bone pain, muscle weakness, frequent fractures, or symptoms of low calcium such as tingling, muscle spasms or cramps. Do not take high-dose vitamin D for long periods without medical advice, as too much can raise calcium levels and harm the kidneys and heart.

What vitamin D does

Helps the gut absorb calcium and phosphate.
Keeps bones and teeth strong.
Supports normal muscle function.
Plays a role in the immune system.
Is made in the skin from sunlight (UVB) and found in a small number of foods.

Common symptoms of vitamin D deficiency

Bone pain or tenderness, especially in the lower back, hips, legs and ribs.
Muscle aches and weakness, particularly in the thighs and upper arms.
Difficulty climbing stairs or getting up from a low chair.
Tiredness and fatigue.
Muscle cramps or twitches, sometimes linked to low calcium.
In children: bowed legs, delayed growth, delayed walking and dental problems (rickets).

Less obvious signs and associations

A waddling walk due to weakness of the hip muscles in severe deficiency.
Tenderness when pressing on the shin or breastbone.
Stress fractures or fractures after minor falls.
Low mood: studies show associations, but supplements have not consistently improved mood in people without deficiency.
Frequent infections: low vitamin D is linked with respiratory infections in some studies.
Hair loss and slow wound healing: weak associations, not proven causes.
These symptoms have many other causes, so testing is the only way to know.

Who is at risk?

People who spend little time outdoors, including housebound people and care home residents.
People who cover most of their skin when outside.
People with darker skin, who need more sun exposure to make vitamin D.
Older adults, whose skin makes less vitamin D.
Babies and young children, pregnant and breastfeeding women.
People with obesity.
People with conditions affecting absorption, such as coeliac disease, Crohn’s disease or after bariatric surgery.
People with kidney or liver disease, and those taking some anti-epileptic medicines.

How vitamin D deficiency is diagnosed

Vitamin D status is measured by a blood test for 25-hydroxyvitamin D. Cut-off values vary between organisations. In the UK, levels below 25 nmol/L are generally considered deficient. The Endocrine Society guideline defines deficiency as below 50 nmol/L (20 ng/mL) and insufficiency as 52–72 nmol/L (21–29 ng/mL). Testing is usually recommended for people with symptoms or high risk, rather than for everyone. Doctors may also check calcium, phosphate and parathyroid hormone levels.

How much vitamin D do you need?

The NHS recommends 10 micrograms (400 IU) a day for adults and children over one year, from autumn to spring.
People at higher risk are advised to take 10 micrograms all year round.
Babies under one year need 8.5–10 micrograms a day unless they drink more than 500 ml of formula, which is already fortified.
US recommendations are 600 IU (15 micrograms) for most adults and 800 IU for people over 70.
If you are deficient, a doctor may prescribe higher treatment doses for a limited time.
Do not take more than 100 micrograms (4,000 IU) a day unless advised by a doctor.

Food sources of vitamin D

Oily fish such as salmon, mackerel, sardines and herring.
Egg yolks.
Red meat and liver (liver should be avoided in pregnancy).
Fortified foods, such as some breakfast cereals, spreads, plant milks and yoghurts.
Mushrooms exposed to UV light.
Vitamin D works alongside other nutrients for bone health, such as calcium and vitamin K; see vitamin K2 foods.
It is hard to get enough from food alone, which is why supplements are advised in winter.

Sunlight and vitamin D

From around late March to the end of September in the UK and similar latitudes, most people can make enough vitamin D from short periods of sunlight on the forearms, hands or lower legs, without sunscreen, around the middle of the day. The time needed varies with skin colour and the season. Take care not to burn. In autumn and winter, the sun is not strong enough at these latitudes, which is why supplements are recommended.

Can you have too much vitamin D?

Taking too much vitamin D in supplements over a long period can lead to high calcium levels (hypercalcaemia), which can cause nausea, vomiting, thirst, confusion, kidney stones and heart rhythm problems. You cannot get too much vitamin D from sunlight. Stick to the recommended daily dose unless a doctor has prescribed more, and check how much is in multivitamins and combined supplements.

Three common situations

Office worker feeling tired every winter: take a daily 10 microgram supplement and see a doctor if tiredness persists, as there are many other causes.
Older adult with aching hips and difficulty with stairs: ask about testing vitamin D and bone health.
Breastfed baby: give a daily vitamin D supplement from birth as recommended.

Key points to remember

Vitamin D deficiency often causes no symptoms.
Bone pain, muscle weakness and tiredness are the most typical signs.
Most people should take 10 micrograms a day in autumn and winter.
A blood test confirms deficiency; avoid long-term high doses without advice.

Questions about vitamin D deficiency

These answers are general information and do not replace an examination or individual medical advice.

What are the first signs of low vitamin D?

Often there are none. When present, tiredness, aches and muscle weakness are common early signs.

Can low vitamin D cause anxiety or depression?

Low levels are associated with low mood in some studies, but supplements have not consistently been shown to treat depression.

How long does it take to correct vitamin D deficiency?

With treatment doses prescribed by a doctor, levels usually improve within a few weeks to months.

Can vitamin D deficiency cause hair loss?

Some studies link low vitamin D with hair loss, but it is not proven to be a direct cause.

Should I get my vitamin D tested?

Testing is useful if you have symptoms or are at high risk. Most people can simply follow supplement advice.

Sources

This guide is for general information and does not replace medical advice. How a problem is diagnosed and treated depends on your examination and medical history. If you think you have an emergency, contact your local emergency services.