Banned sports supplements easily available online: study

Sports supplements containing banned substance DMAA can easily be bought online, for example in online stores or through Dutch sports influencers on Instagram, according to research by NOS and masters students from the University of Amsterdam. The majority of these so-called pre-workout shakes are legal, but on Instagram and foreign online stores shakes with banned substances can also easily be bought, according to the broadcaster.

These types of supplements are increasingly popular, particularly among young people who want a boost before heading to the gym, according to figures from market researcher Euromonitor. Most of these powders are relatively harmless, though doctors warn of high doses. They contain a lot of caffeine as well as other "uppers" such as citrulline and beta-alanine.

"But there are also often very different substances in the powder mixtures", Bastiaan Venhuis of public health institute RIVM said to NOS. "We come across everything. Sometimes the amounts of the active substances on the labels are not correct. Or there is something else in there that's not on the label, sometimes even prohibited substance DMAA."

DMAA is a substance similar to amphetamine [speed], according to the broadcaster. It was banned in 2012 after deaths during exercise were linked to it in 2012. The ban was precautionary - there were no long-term studies into the side-effects of DMAA. A high dose of DMAA can lead to side effects like heart palpitations, insomnia and anxiety attacks.