Conor McGregor Allegedly Used ‘Banned Drugs’ to Heal 2021 Leg Injury

Conor McGregor is facing allegations of using banned drugs to treat a leg injury sustained in a 2021 UFC fight, according to reports from MMA Fighting and The New York Times. The claims, first published by MMA Fighting on June 11, 2026, allege that the Irish mixed martial artist utilized substances prohibited by the United States Anti-Doping Agency (USADA) to expedite recovery from a fractured tibia during his bout against Dustin Poirier at UFC 264 on July 10, 2021.

The reports cite unnamed medical sources and internal documents obtained by MMA Fighting, which describe McGregor’s treatment protocol as involving “unauthorized regenerative therapies” not approved by the UFC’s medical commission. The New York Times, which also covered the story, quoted a source familiar with the investigation stating that McGregor’s medical team “departed from standard procedures” by administering “growth factor-based treatments” linked to performance-enhancing drug (PED) guidelines. Neither the UFC nor USADA has publicly confirmed the allegations, and McGregor’s representatives have not responded to requests for comment.

Medical Context and Injury Details

McGregor sustained the leg injury during his highly anticipated rematch against Poirier, a fight that ended in a controversial split decision in favor of Poirier. The fracture, diagnosed as a tibial plateau break, required surgical intervention and a prolonged recovery period. According to the MMA Fighting report, McGregor’s rehabilitation included treatments involving platelet-rich plasma (PRP) injections and stem cell therapy, which are generally permitted under UFC regulations. However, the allegations center on additional substances not disclosed in public medical records, which the report claims were administered under the supervision of Dr. James Andrews, a renowned orthopedic surgeon known for treating elite athletes.

Dr. Andrews, who has not commented on the specific case, has previously stated that PRP and stem cell therapies are “generally safe and within regulatory boundaries” when used for injury recovery. However, the MMA Fighting report suggests that McGregor’s team may have combined these treatments with “unlisted compounds” to accelerate healing, a practice that could violate anti-doping rules if the substances are classified as performance-enhancing. The UFC’s official policy prohibits the use of any substance listed by USADA, including those with potential anabolic or growth-stimulating properties.

Previous Allegations and UFC Response

This is not the first time McGregor has faced scrutiny over his medical treatments. In 2020, the UFC temporarily suspended him for failing a drug test, though the results were later dismissed due to procedural errors. The organization has since emphasized its commitment to “strict adherence to anti-doping protocols,” according to a statement released by UFC spokesperson Marc Ratner in 2023. “The UFC takes all allegations of doping seriously and works closely with USADA to ensure the integrity of our sport,” Ratner said at the time.

The New York Times article, published on June 11, 2026, criticized McGregor for “prioritizing speed over transparency” in his recovery process. The piece noted that while PRP and stem cell therapies are widely used in sports medicine, the inclusion of “unspecified additives” raises questions about compliance. “The line between therapeutic and performance-enhancing is often blurred, but when athletes are under investigation, the burden of proof lies with them,” the article stated.

What Comes Next?

The allegations have sparked renewed calls for transparency from anti-doping advocates. Dr. Kevin Tuite, a sports medicine expert and former USADA official, told ESPN that “if the UFC or USADA finds evidence of prohibited substances, McGregor could face sanctions including suspension or fines.” However, he added that “without concrete evidence, this remains an allegation, not a confirmed violation.”

McGregor, who has not fought since 2022, has been vocal about his desire to return to the octagon. His last public appearance was a 2025 interview with ESPN, where he described his recovery as “100% complete” and hinted at a potential comeback in 2027. The latest reports could complicate his return, as the UFC typically requires athletes to undergo mandatory drug testing before resuming competition.

As of June 12, 2026, no official action has been taken against McGregor. The UFC has not issued a statement, and USADA has not confirmed an ongoing investigation. However, the organization’s compliance team is reportedly reviewing the allegations, according to a source with direct knowledge of the matter.

The situation underscores the ongoing challenges in regulating medical treatments in combat sports. While therapies like PRP and stem cell injections are increasingly common, their use remains contentious in the context of anti-doping rules. For McGregor, the allegations risk further damaging his reputation, already tarnished by past controversies including a 2023 legal dispute with the UFC over contract terms.