The difference, I believe, is others give an explanation of the test
The BBCs Panorama says that Farah was injected four times with L-carnitine two days before the 2014 London marathon by UK Athletics chief medical officer at the time, Dr Rob Chakraverty with UKA head of distance running Barry Fudge, former UKA performance director Neil Black and Alberto Salazar also present
Scientific opinion on dietary reference values for niacin
doi: 10.1038/nrdp.2016.67 8
In rodents, activation of AMPA receptors by the KET metabolite (2R,6R)-hydroxynorketamine has initially been thought essential to replicate KET antidepressant effects while administration of 2,3-dihydroxy-6-nitro-7-sulfamoyl-benzo[f]quinoxaline-2,3-dione (NBQX), an AMPA receptor antagonist, blocks KET effects (Zanos et al., 2016)