Tristan Thompson was suspended from the NBA for a drug violation. Here's why the 2 substances found in his system are banned.

• Cleveland Cavaliers center Tristan Thompson has been suspended from the NBA for 25 games.
• The 32-year-old tested positive for a pair of substances prohibited by the league's anti-drug program.
• The two substances — ibutamoren and LGD-4033 — can be performance enhancing. Here's what they do:

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Cleveland Cavaliers big man Tristan Thompson has been suspended without pay from the NBA for 25 games.

The 32-year-old NBA champion tested positive for a pair of substances prohibited by the league's anti-doping program, according to an NBA release published Tuesday. The two drugs found in Thompson's system — ibutamoren and LGD-4033 — can be used for performance enhancement purposes and may have dangerous side effects.

According to the NIH, ibutamoren is a growth hormone secretagogue, or a substance that promotes the production of growth hormones. Heightened growth hormone in one's system can increase muscle mass, limit body fat, and improve exercise tolerance, per Mayo Clinic.

Likewise, LGD-4033 — also known as Ligandrol — can stimulate muscle growth and improve physical functioning, according to the NIH. LGD-4033 belongs to a class of drug called SARMs, or selective androgen receptor modulators, which are designed to mimic the effects of testosterone on the body, but can also have dangerous repercussions.

Dubbed "legal steroids" despite their dubious legal status, SARMs like LGD-4033 can increase the risk of heart attack, liver failure, sexual dysfunction, and psychosis, the FDA warns. Ibutamoren, meanwhile, has been associated with the potential for congestive heart failure in patients, per the FDA.

Both drugs are banned by the NBA as well as sports governing bodies such as the NCAA and the World Anti-Doping Agency.

Thompson is not the first NBA player found with such substances in his system. In 2017, then-New York Knick Joakim Noah earned a 20-game suspension after testing positive for LGD-4033 while taking supplements in an attempt to expedite his return from injury, according to the league.

The following year, then-Washington Wizards guard Jodie Meeks missed the 2018 playoffs and the start of the following season after testing positive for ipamorelin, a growth hormone secretagogue similar to ibutamoren. And in 2019, John Collins — then with the Atlanta Hawks — spent 25 games on the sidelines after the league found pralmorelin, another growth hormone secretagogue, in his system.

Thompson, who has averaged just over 12 minutes per game this season in Cleveland, will be eligible to return to the court in mid March. The Cavaliers, who currently sit in fourth place in the Eastern Conference, will look to maintain their playoff positioning without the center as he completes his 25-game suspension.