This goes for a lot of things in this field but it's particularly pertinent when it comes to buying supplements. Words of wisdom from Arthur Jones.... IRONMAN, May 1972 Volume 31 Number 4:
"In the meantime I would advise all trainees to buy their products from people that they respect -- and I would also advise them to extend their respect very, very carefully; the size of a man's arm has no relationship with the size of his brain, and even less relationship to his honesty and integrity all three of which items, brains, honesty, and integrity, seem to be in very short supply in this field at the moment"
For those that don't know, Arthur Jones is credited with pioneering the theory of High Intensity exercise (H.I.T. theory) and mentored Mike Menzer (Heavy Duty), who in turn influenced Pete Sisco and John Little (Power Factor Training/Static Contraction Training), etc.. His Nautilus Bulletins originally published in IronMan were classics and still hold much value for today's lifter.