Britons taking a host of over-the-counter supplements are risking organ damage  and even death by missing out on a crucial protective step, experts have warned.

A survey of over 2,000 Britons by product testing website Which? found three quarters take supplements and about one in five take four or more each day. 

However, 37 per cent admitted to not talking to GP or other health professional before starting them, and undergoing blood tests. 

Dietitian Nichola Ludlam-Raine said missing this critical step puts them at risk overdosing on a vitamins or minerals which, in some cases, can have dangerous effects.

Other potential dangers include supplements interacting with commonly taken medications, making vital drugs less effective, or more potent.

One example is cinnamon supplements which can exacebate the impact of blood thinning medication, raising the risk of a life-threatening, major bleed. 

Ms Ludlam-Raine added that self-prescribing supplements could also lead to signs of serious and even life threatening-health conditions going unchecked.

‘I’d always recommend speaking to a registered dietitian, pharmacist or doctor before starting a new supplement routine, especially if someone is on medication or has a medical condition,’ she said. 

The survey sampled 2,514 UK adults aged 18 to 65 and above about their supplement use in March 2025

‘Our biggest issues is that people self-prescribe based on what they see online or their family suggest.

‘Without knowing what they need or if they need anything at all, they may risk overdosing, or miss the real and potentially serious reason behind a symptom such as fatigue or hair loss.’

The Which? survey suggests supplement misinformation may be particular problem among young people. 

About one six adults aged 18 to 34 who responded to the survey admitted getting their supplement information on TikTok.

‘Social media is a formidable channel for selling and promoting products now in a way it wasn’t a decade or so ago, and this presents fresh challenges,’ Which? said. 

Amid the concerning results of their survey, Which? shared information on some of the most common supplements reported to cause harm.

In particular, supplements they advised taking most care with were vitamin A, vitamin B6, and turmeric.

They warned vitamin A should not exceed 1.5mg per day and not be taken at all if you’re pregnant or trying to conceive.

In the report by product testing website Which, experts flagged the dangers of taking too much of popular supplements

However, MailOnline have discovered vitamin A supplements on online marketplaces like Amazon that contain double the daily maximum recommended amount in a single dose.

Too much of the vitamin has been linked to liver damage and bone strength problems, according to The European Union Scientific Committee on Food. 

Some studies have found having too much of it over many years makes the bones more likely to fracture in older age. 

Other research has suggested vitamin A and other forms of the nutrient, like beta-carotene, may increase risk of lung cancer, particularly for smokers. 

The watchdog also warned against taking very high doses of vitamin B6. Doses above 200mg can lead to loss of feelings in the arms and legs (known as peripheral neuropathy), the NHS has warned.

MailOnline has identified several products sold online that contain more than ten times this upper recommended daily dose of B6 in a simple capsule.

The last supplement they warned to be extra careful of is curcumin supplements; a derivative of the popular spice, turmeric.

While using turmeric as a spice in cooking is safe, the Which? experts warned high doses of curcumin can lead to liver toxicity, which can be life-threatening. 

The experts warned that too much turmeric in supplements particularly if combined with black pepper can lead to liver damage

Curcumin supplements are the most common cause of supplement-related liver injury in the US, according to LiverTox, which is an online resource on how drugs and supplements can cause liver damage.

In particular American researchers found liver damage took place where the supplement featured the spice in combination with black pepper.

This is because pepper changes the way the body absorbs the compound, explained Dr Dina Halegoua-DeMarzio, director of the Fatty Liver Center at Thomas Jefferson University Hospital, in the US.

In some people, taking one pill of curcumin and pepper would be as potent as taking 20 pills at once with curcumin alone, she said.

It comes after a pharmacist urged gym-goers to avoid popular pre-workout powders due to severe damage they could do to your heart.

Many supplements that claim to boost energy and exercise performance contain extremely high quantities of caffeine.

This can, over time, increase blood pressure to dangerous levels and trigger heart rhythm abnormalities, according to Ireland-based drug expert, Lauren O’Reilly.

In a recent video posted to her TikTok that has amassed over 82,000 views, Ms Reilly said she ‘wouldn’t touch’ the powders.

‘They contain over 300mg [of caffeine] per scoop or per serving, which is the same as having three cups of coffee all at once,’ she warned.