UFC Fighter Sues Vitamin Company, You Snuck Steroids Into Workout Supplement

UFC fighter Lyman Good claims his multi-vitamin was tainted with an illegal steroid, causing him to fail a drug test -- and now he's suing the vitamin companies allegedly responsible for his dirty test.

TMZ Sports has obtained the lawsuit filed in New York ... in which Good claims he went to a Vitamin Shoppe store before his fight at UFC 205 and purchased Anavite, a multi-vitamin.

Good claims he failed his USADA drug test -- which came up positive for 1-andro ... an illegal anabolic steroid.

Good says he turned over all of his supplements to the United States Anti-Doping Agency (USADA) for further testing and it showed Anavite secretly contained 1-andro ... despite the fact it was not advertised or properly mentioned on the label.

In his suit, Good claims the manufacturer -- Gaspari Nutrition -- intentionally added the steroids in order to "increase sales in the competitive dietary supplements industry."

Good is suing Gaspari and The Vitamin Shoppe (among others), claiming the store didn't honor its promise to "enforce strict quality assurance." He's seeking unspecified damages.

FYI, Good was ultimately hit with a 6-month ban for his positive drug test -- and he claims the whole ordeal has damaged his career.

A company spokesperson for The Vitamin Shoppe says, "It has come to our attention that the multivitamin, Anavite, by Gaspari Nutrition, has been alleged to contain an undisclosed ingredient."

"We take these issues very seriously and as a precautionary measure, we are removing this supplement from our stores and our website while we review this matter. Our customers' safety is our priority and we are committed to providing quality products they can trust."

We reached out to Gaspari, but they didn't have a comment.