Key warning signs you're taking too many vitamins as the five most dangerous revealed

Vitamins have never been more popular: Walk into any pharmacy or scroll through social media and you'll find endless promises about supplements that can transform your skin, boost your energy and slow down ageing.

But experts are now warning that more is not always more, and that taking too many vitamins can cause serious harm, including nerve damage, heart problems and hair loss.

Dr Tina Ghela from Medichecks says the issue is more common than most people think. "Over supplementing can absolutely have negative health effects," she explains.

"This can be anything from nausea, diarrhea, difficulty sleeping to even mild nerve damage, amongst other things."

Crucially, Dr Ghela points out that most people don't need to be taking supplements at all.

"There are 13 essential vitamins that we should all be getting into our diet on a regular basis, but most people will get all the vitamins and minerals they need through eating a healthy, balanced diet."

She also flags that many everyday foods already have vitamins and minerals added to them, meaning that on top of a balanced diet, many people are already inadvertently over-supplementing without realising it.

“over supplementing can absolutely have negative health effects, this can be anything from nausea, diarrhoea, difficulty sleeping to even mild nerve damage, amongst other things.” (Getty stock image)

Can you accidentally overdose on vitamins?

Part of the problem, according to Dr Ghela, is the sheer volume of outside influences pushing people towards supplements skincare trends, wellness culture, anti-ageing content, which can lead people to start stacking multiple products without considering the combined effect.

"Most people don't realize that they are even overdosing," she says.

"We are so wired to believe that we need to get our daily vitamin and mineral intake that the thought of over supplementing doesn't cross our minds."

Her advice is straightforward: if you are taking supplements, stick to one. "If you are taking a multivitamin, do not take any other 'wellbeing' supplements," she warns, adding that anyone considering vitamins should speak to a medical professional first rather than self-prescribing based on social media recommendations.

When the body is constantly over-supplemented, the impact can be felt across multiple systems.

Symptoms range from nausea, vomiting, dizziness and fatigue to rashes, hair loss and muscle weakness, with the specific effects depending on which vitamin is being taken in excess.

"Most people though do not need to take supplements as they will get all the vitamins and minerals they need through eating a health, balanced diet." (Getty stock image)

The five vitamins most dangerous to overdo

Dr Ghela identifies five vitamins as particularly risky when taken in excess. Vitamin C, often assumed to be completely harmless, can cause nausea and diarrhea when consumed in too high a quantity.

Selenium, found in many general wellness supplements, can trigger hair loss, fatigue, stomach problems and even nerve damage.

Vitamin D is perhaps the trickiest case. Many adults are genuinely deficient, particularly in winter, making supplementation sensible for a large portion of the population.

But Dr Ghela warns it is also one of the more concerning vitamins to overdose on: exceeding the safe upper daily limit can lead to serious heart problems and a build-up of calcium that damages the bones and kidneys.

Vitamin A and beta-carotene present their own unusual side effect, consuming too much can actually turn the skin orange.

And finally, excess Vitamin K, though a rare deficiency, can interfere with blood clotting and lead to increased bleeding.

The CDC advises that before taking any supplement, individuals should consider whether their diet already meets their nutritional needs.

Medichecks offers a Health and Lifestyle blood test for anyone who wants to establish whether their diet is already providing what they need before reaching for another pill.