Teen gamers are guzzling worrying amounts of stimulants with as much caffeine as five cans of Coke.
Console addicts are promised the powdered drinks will keep them alert.
But medics warn one sachet contains double the advised level of caffeine per day for teens.
Experts fear too much can cause insomnia, anxiety, dehydration – and lift heart rate and blood pressure.
Dr Aishah Iqbal warned: “Teenagers should consume no more than 100mg of caffeine per day – the majority of these gamer energy drinks contain far more in one serving.
"Young people could consume very high amounts of caffeine in a single session”.
X-Gamer’s Hyperbeast boasts it is “formulated exclusively for esports, semi-professional & enthusiast gamers” with “vitamin-packed energy” and “zero added sugar”.
But the brew – £32.90 for 60 drinks on Amazon – also contains 200mg caffeine per serving and a raft of additive E numbers.
The £32 G Fuel tub – with 140mg of caffeine per serving – is also on Amazon.
But one review warns: “Two servings is the limit, going over will cause sickness and hallucinations.”
A 250ml can of Red Bull contains 80mg of caffeine. Coca Cola has 40mg.
Nutritionist Lamorna Hollingsworth said of the gamers’ drinks: “They are easily gulped down which leads to dangers of heart palpitations, high blood pressure, nausea, vomiting and hyperactive behaviour.”
Former school head Sarah Dove, who runs Phoenix Education Consultancy said: “A balance, where children can work, rest and play is vital for physical and emotional well-being.”
Amazon declined to comment. X Gamer and G Fuel were approached.
The Tories vowed to end energy drink sales to under-16s in 2019.
A spokesman said it will give details “in due course”.
