The food safety watchdog has issued new guidance over caffeine in food supplements after a man died miscalculating the amount he was meant to use.

Personal trainer Tom Mansfield, from Colwyn Bay, Conwy county, died in January 2021 after taking caffeine powder which was equivalent to up to 200 cups of coffee.

Highly-concentrated caffeine supplements can be “extremely potent”, the Food Standards Agency (FSA) and Food Standards Scotland (FSS) warned.

The watchdogs advise people to always follow the dose instructions on the label and use accurate measuring equipment.

Dad-of-two Mr Mansfield tried to weigh a dose of the powder within a range of 60 milligrams to 300 milligrams using a scale that had a weighing range of 2g-5,000g, meaning he ended up consuming several grams.

Since then, a cross-government working group has considered broader issues surrounding the sale and consumption of caffeine supplements, including commissioning additional research.

A survey for the watchdogs suggested less than half of people look for dosage instructions on supplements, with 20% saying they did not read the label.

Research also found that many consumers have limited or no knowledge of caffeine in food supplements.

Caffeine is used by some gym-goers, with some fitness websites recommending it for improving sports performance in certain doses.

FSA and FSS guidance says supplements with caffeine should be calculated alongside other sources of caffeine, such as coffee, tea and energy drinks.

Caffeine intakes of up to 400mg per day are unlikely to cause adverse effects in adults, but pregnant women are advised to limit their consumption to 200mg.

At very high levels caffeine can cause anxiety, sleeplessness and diarrhoea, while those with mental health conditions can experience worsened psychosis.

These effects may be more severe in individuals who are caffeine sensitive or who have underlying health issues such as heart disease or high blood pressure.

FSA chief scientific adviser Prof Robin May said: “Pure and highly concentrated caffeine supplements such as caffeine powder can be extremely potent, so you should always follow the dose instructions on the label and use appropriate measuring equipment to make sure it’s accurate.”