DMAA, or methylhexanamine in full, has been implicated in the death of London Marathon runner, Claire Squires.
Although not technically banned, DMAA has been classed as a medicinal substance that can only be sold with a licence.
So what is the drug, and what harm can it do?
- DMAA was trademarked as Forthane in 1944 and was originally marketed as a nasal decongestant.
- It was re-marketed in 2006 as a dietary supplement.
- DMAA is often combined with caffeine in supplements designed to promote fat loss (as a thermogenic) and energy during workouts (as a stimulant).
- It was removed from the UK market in 2012 due to "concerns of potential risks to public safety".
- DMAA is banned by the World Anti Doping Agency which classes it as a performance enhancing drug.
- Physiological effects of DMAA include raised heart rate and narrowing of the arteries.
- There have been 137 incidents of professional athletes abusing the drug.
- The drug has been implicated in the deaths of two US soldiers who collapsed and died during physical training in 2012.
David Carter, the Manager of the Medicines and Healthcare products Regulatory Agency said: "People need to be aware when choosing their sports supplements.
"These products may claim to increase performance but contain powerful ingredients which can have serious side-effects.
"We recommend that people only use approved products and speak to a qualified medical practitioner if they have any concerns about any supplements they may be taking.”