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In the week leading up to the Games, 5 live's Nicky Campbell spent seven days taking a 'performance-enhancing' substance which is not allowed in the Olympics. It's called methylhexaneamine, or MHA, and it's the stimulant that Yohan Blake, the man who recently beat Usain Bolt, has served a ban for. It's in some supplements you can buy, perfectly legally, in high street fitness shops in the UK.

The supplement is not currently subject to any controls but there is a question mark over its safety. The government's regulator, the Medicines and Healthcare Products Regulatory Agency, is seeking to have it reclassified as a medicine, rather than a supplement.

After a medical check-up, Nicky was joined by Michelle Dignan to see how he performed, supplement-free. Seven days later, having taken the supplement, Nicky repeats the workout with support from 5 live's George Riley.