The sourcing of many vitamin supplements is murky at best.
When exercise and nutrition coach Ryan Andrews was researching his story for Precision Nutrition on how vitamins and minerals in nutritional supplements are sourced, he ran into some interesting—and frankly, ironic—informational barriers.
"I emailed Nature Made about vitamin B-1," Andrews writes. "They said: 'We appreciate your questions concerning our supplements. Nature Made Vitamin B-1 is manufactured in a laboratory from chemicals. It is synthetically made in our manufacturing facilities in Southern California.'"