14 signs of vitamin D deficiency

Vitamin D soft capsules

Would you know the signs of vitamin D deficiency?

Whilst the symptoms of low vitamin D levels can vary between individuals, the telltale signs typically include tiredness and fatigue, poor bone health and muscle weakness. Vitamin D deficiency can, however, manifest in many different ways, and it’s typically diagnosed based on a blood test rather than symptoms.

Keep reading to discover 14 signs of vitamin D deficiency that could be affecting you, paying extra attention if you’re at an increased risk of low vitamin D! People with a higher risk of vitamin D deficiency include those who are over 65, have darker skin or a malabsorption disorder like coeliac disease, and those who get very little sun exposure.

Tiredness and fatigue

Does low vitamin D make you tired? Yes, studies have shown that there is certainly a link between fatigue and vitamin D deficiency, finding that people with low levels of vitamin D can see an improvement in their fatigue upon taking vitamin D supplements consistently.

If you’re suffering with unexplained fatigue, you should consider making an appointment with your GP so they can issue a blood test to see if your vitamin D levels are low.

Poor bone health

Vitamin D helps your body to absorb calcium and phosphorus from the food you eat, both of which are vital nutrients for keeping your bones healthy.

Having low levels of vitamin D can lead to low bone mass and bone pain. Vitamin D deficiency may also increase your risk of osteomalacia and osteoporosis, both of which make your bones more likely to fracture and break.



Dry skin conditions

Research has shown that in people with vitamin D deficiency, skin is more likely to become dry and prone to eczema and psoriasis. This may be linked to a potential link between vitamin D and skin moisture; a study found that those with low vitamin D had lower average skin moisture than those with normal vitamin D levels.

Eczema and psoriasis are common skin conditions, and a lot of people suffer with dry skin during the autumn and winter months, so these issues might not necessarily be caused by vitamin D deficiency.

If you’re concerned about your dry skin and suspect you may have low vitamin D levels, see your GP for a blood test or consider a vitamin D supplement.

Increase in illnesses or infections

Many vitamins and minerals are known to contribute to the healthy function of the immune system, and vitamin D is no exception. It’s thought to boost the immune cells’ production of infection-fighting proteins and lessen the inflammatory response of white blood cells.

If you have vitamin D deficiency, your immune system might not be working at its best. This means you may experience illnesses and infections like the common cold or flu more often than you usually would.

Back pain

As vitamin D contributes to bone health, a lack of vitamin D may result in back pain. What’s more, vitamin D has been shown to provide some anti-inflammatory benefits and may reduce muscle soreness after exercise.

So, if your back has been aching and you’re not sure why, consider popping a vitamin D supplement regularly to see if you notice any improvement.


Research has found that vitamin D deficiency may be associated with an increased risk of depression, or that it could make existing depression worse. There’s also thought to be a connection between seasonal affective disorder (SAD) and low levels of vitamin D.

If you’ve noticed any symptoms of depression or seasonal affective disorder, such as a persistent low mood or a loss of interest in your normal activities, you should visit your GP for advice. Taking a vitamin D supplement might help you in the long run, but depression can be serious and isn’t something you should try to tackle alone.

Decreased wound healing

Have you noticed simple cuts and grazes are taking a long time to heal? You could be dealing with vitamin D deficiency. A study has found a strong correlation between low levels of vitamin D and hard-to-heal wounds.

If you have a wound that won’t heal, see your doctor. Whilst a vitamin D deficiency could be at fault, it’s best not to make assumptions. Slow wound healing can also be a symptom of an infection, poor circulation or even diabetes.

Hair loss

Hair loss can be caused by a range of issues, including vitamin D deficiency. In fact, a recent study found that low vitamin D levels could be linked to the severity of androgenetic alopecia in men (male pattern baldness).

Beauty comes from within, so making sure we’re getting the right levels of essential vitamins and minerals, including vitamin D, is vital for retaining thick, luscious hair.

Muscular pain

The cause of chronic muscle pain and weakness can be hard to pinpoint, and it’s a problem that affects a lot of us as we get older. Levels of vitamin D also tend to decrease as we age.

Evidence suggests there could be a correlation between chronic pain and vitamin D deficiency. One study even found that vitamin D supplements significantly decreased the severity of growing pains in children.

If you’ve noticed unexplained muscular pain, you could try taking a vitamin D supplement for a few weeks to see if there’s any improvement.

Weight gain

Some studies have found that people who are overweight or obese tend to have lower levels of vitamin D, leading to suggestions that low vitamin D could cause weight gain. The evidence for this, however, is limited.

Weight gain occurs when you eat more calories than you burn, and the only way to lose weight is by burning more calories than you’re eating. That said, taking a vitamin D supplement is great for your overall health, so there’s no harm in seeing if this helps your weight management.


Anxiety is one of the most common mental health problems, with over 8 million people in the UK experiencing an anxiety disorder at any one time. Researchers have found a potential link between vitamin D deficiency and anxiety, with one study finding that taking a vitamin D supplement may improve anxiety.

Everyone experiences feelings of anxiety from time to time, but you should visit your GP if anxiety is affecting you more than usual or if it’s having a significant negative impact on your life.

Rickets (in children)

Rickets is a condition that causes bone pain, poor growth and soft, weak bones in children. It’s generally caused by a lack of vitamin D or calcium, as these are essential for the formation of strong and healthy bones in children.

The NHS advises that from birth, all breastfed babies should be given a daily supplement of vitamin D (8.5 to 10mcg). Once your baby is six months old, daily vitamin A, C and D supplements are recommended up until they’re five (unless they're having over 500ml of infant formula each day).

Asthma (in children)

Clinical studies have found that vitamin D plays an important role in the development of childhood asthma. It was found that children with severe asthma had significantly lower levels of vitamin D than those with moderate asthma.

You must seek medical attention if your child is presenting any of these symptoms of asthma:

  • Wheezing when breathing out
  • Frequent coughing triggered by exercise or cold air
  • Shortness of breath
  • Chest congestion or tightness

If these symptoms are severe and sudden, your child may be having an asthma attack and you must call 999.

Cognitive impairment in older adults

As we age, our skin gets thinner and loses more than 50% of its ability to produce vitamin D at 70 years old compared to 20 years old. Vitamin D keeps our blood vessels healthy and ensures nutrient-rich blood can flow to our brain cells.

Low levels of vitamin D have been linked to dementia; one study found that vitamin D deficiency was associated with an increased risk of dementia and stroke.

The causes of dementia are constantly being researched, but taking a regular vitamin D supplement may help to prevent or slow down cognitive decline as you get older. You can learn more about reducing your risk of dementia in our guide.

Sometimes, low levels of vitamin D won’t display any symptoms at all. The NHS recommends that we should all consider taking a 10 microgram (400IU) vitamin D supplement during the autumn and winter months, even if no symptoms are present. This is because the best source of vitamin D is exposure to sunlight, and we don’t get enough of it here in the UK when our days are shorter.

It’s also important to note that many of these symptoms could be indicating another problem other than vitamin D deficiency. If you’re not sure what’s causing you to feel unwell, especially if you’re experiencing severe symptoms such as asthma or depression, make sure to visit your GP so they can investigate the problem.

Faye Bonnell - Medical Content Writer
James O'Loan - CEO & Superintendent Pharmacist
James O'Loan , CEO & Superintendent Pharmacist on 07 February 2024
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