What you need to know about Ostarine, the drug found in Wildcats star Allonzo Trier's system

Allonzo Trier has trace amounts of the drug Ostarine in his system, his attorney says, which is why the NCAA has ruled the UA basketball standout ineligible to play.

Ostarine is the same drug that Trier says he inadvertently ingested in September 2016. A "minuscule amount" was detected in Trier's most recent drug test, the UA said. Here's a look at the drug, how it got into Trier's system and what may be next for the Arizona Wildcats star: 

Ostarine is a selective androgen receptor modulator (SARM) used to treat osteoporosis and combat muscle wasting in the elderly. The World Anti-Doping Agency banned Ostarine in 2008 because, it said, the drug can produce effects similar to anabolic steroids. WADA reports an increase of positive tests for Ostarine in recent years; the organization says most athletes obtain the drug through black-market channels. 

Ostarine is not approved by the U.S. Food and Drug Administration, meaning doctors do not (and could not) prescribe it to their patients. It's available over the internet, however, and via black-market channels.

In October, the FDA issued warning letters to Infantry Labs, LLC, IronMagLabs and Panther Sports Nutrition for distributing products that contain SARMs, including Ostarine. Their products were labeled as dietary supplements, but in fact included performance-enhancing drugs.

"We are extremely concerned about unscrupulous companies marketing body-building products with potentially dangerous ingredients. Body-building products that contain selective androgen receptor modulators, or SARMs, have not been approved by the FDA and are associated with serious safety concerns, including potential to increase the risk of heart attack or stroke and life threatening reactions like liver damage,” said Donald D. Ashley, J.D., director of the Office of Compliance in the FDA’s Center for Drug Evaluation and Research. “We will continue to take action against companies marketing these products to protect the public health."

Trier's stepfather initially gave him Ostarine mixed into a drink back in 2016, Trier's attorney, Steve Thompson, told Yahoo Sports on Thursday. Trier had previously refused to say which drug prompted the positive test or who gave it to him, only to say that it was someone "misguided."

Trier told the NCAA that he consumed the drink without knowing what was in it. The governing body agreed, ruling then that he could play once the drug was out of his system. Trier was cleared to play in time for the Wildcats' Jan. 21, 2017 game against UCLA, a win. He continued to pass drug tests throughout the rest of the 2016-17 season and most of this season.

Traces of Ostarine reappeared in a drug test Trier took late last month. The UA has appealed to the NCAA, saying that the amount — equivalent to a half-dozen grains of sand in multiple Olympic-style swimming pools — isn't enough to give Trier an advantage on the court. Thompson told Yahoo on Thursday that the NCAA's decision to suspend Trier again when he has just trace amounts in his system is mind-boggling.

"Allonzo has never been a drug-cheat, and the NCAA found in 2016 that he never took Ostarine intentionally," Thompson told Yahoo. "The experts tell us Ostarine can be stored in fatty tissues for a long time, and tests can be negative but then later be positive as the substance comes out."

Trier's mom, Marcie, told the Star Thursday night that Trier "did nothing wrong."  

"This is a tragedy not only for him, my family, but also his team, the entire of U of A program and all their beloved fans, followers and alumni." 

UA coach Sean Miller would not discuss Trier's suspension with Star reporters — "I'm good; I gotta go," he said — but told the UA's radio broadcast team that Trier's suspension is devastating. Miller noted that Trier could be reinstated as soon as Friday, though it's unclear how realistic that is. The NCAA could enforce its initial ruling — that Trier can play when the drug is out of his system — but it's unclear how often he'd be allow to test, and how long results would take. The NCAA could also treat Trier's failed test separately from his first, which would certainly lead to longer-term suspension. 

The NCAA is famously inflexible. Allowing Trier to play immediately, with traces of a banned substance still in his system, could open the floodgates for future cases. The NCAA may not want to wade into those waters. 

In a statement issued Thursday, the UA said it was hopeful that Trier could return.

"The University is appealing the decision and is hopeful that Allonzo will regain his eligibility soon," it said.