At the same time, news broke of the first positive anti-doping test among athletes preparing for the Milano Cortina 2026 Winter Olympics — which led to the suspension of 24-year-old Italian Olympic biathlete Rebecca Passler, who tested positive for letrozole — the International Testing Agency (ITA) announced that 92% of athletes have undergone at least one test in the past 6 months as part of the “pre-Games” anti-doping program.

“It is important to understand that the anti-doping system does not operate on the presumption of innocence; rather, a positive test for prohibited substances automatically triggers sanctions, while still allowing the athlete the opportunity to provide explanations,” Federico Schena, PhD, told Univadis Italy, part of the Medscape Professional network. Schena is a professor of sports sciences and director of the Research Center Sport Mountain and Health at the University of Verona and Trento, based in Rovereto in northern Italy.

Drugs Used to Mask Other Substances

Letrozole is among the medications for which an athlete may, in specific circumstances, obtain a therapeutic use exemption. It is an aromatase inhibitor that blocks the enzyme responsible for converting androgens such as testosterone into estrogens, thereby reducing estrogen levels.

The drug is prescribed for certain estrogen-dependent breast cancers. However, the US Anti-Doping Agency explains that letrozole may also be used by individuals taking anabolic steroids to limit unwanted estrogen-related effects — including gynecomastia, fluid retention, and increased abdominal fat — and, in men, to promote higher endogenous testosterone levels by reducing its conversion to estrogen.

Letrozole has numerous potential adverse effects, including elevated cholesterol levels and reduced bone density, as well as hot flashes, night sweats, gastrointestinal disturbances, musculoskeletal pain, fatigue, and insomnia.

“The procedure for obtaining a therapeutic exemption — and therefore authorization to use such medications — is lengthy, highly structured, and complex,” Schena said. “On the one hand, it is essential to protect the right to participate in sport for athletes who genuinely require specific treatments. On the other, it is equally important to prevent this mechanism from being misused by those seeking to bypass the principle of fair play and evade anti-doping rules.”

According to Schena, the situation has improved significantly compared with the past, thanks to a more rigorous approach and, above all, to a substantial increase in both the number and frequency of anti-doping tests at all levels — a trend reflected in the figures released by the ITA.

All Tests Conducted

Since August 2025, more than 7100 anti-doping tests have been carried out on over 2900 athletes included on the short list for the Olympic Games in Italy, representing an approximately 90% increase compared with the previous 6 months for the same athlete population.

The program follows a risk-based approach, classifying sports and disciplines into risk categories that correspond to recommended minimum testing levels. In the group defined as “high risk,” 92% of athletes were tested at least once, and 66% were tested three times or more.

The remaining 8% who have not undergone recent testing will receive heightened scrutiny during the Olympic Games, particularly in disciplines and among athletes deemed “high risk” based on a combination of criteria — physiologic and pharmacologic factors, contextual considerations, and individual athlete profiles — including:

• Sport- or discipline-specific physiologic risks (performance profiles that may be sensitive to certain classes of substances or methods)
• Country-specific risk for that sport (including national doping history, risk profiles, and testing statistics)
• Individual athlete parameters, such as performance trends and testing history
• Additional evidence and data integration, including findings from the so-called biological passport, intelligence, and other information

“The current frontier of anti-doping is the biological passport,” Schena said. “For elite athletes, this involves longitudinal monitoring of physiological parameters over time. While in the past values were measured only sporadically, today the increased frequency of testing — which is widespread at all levels, including amateur sport — not only has a deterrent effect but also generates data that can reveal anomalies that are extremely difficult to explain.”

For anyone competing at an elite level, the relentless pursuit of performance improvement at any cost can expose athletes to serious and sometimes extreme risks, Schena warned.

“When athletes fail to accept the time required for gradual progress, or the constraints imposed by their own physical limits, things can go wrong in many ways,” he said, citing the recent case of a Norwegian biathlete who died, likely as a result of excessive, careless, and inappropriate use of equipment that was not itself prohibited. Univadis Italy reported on the case in December, he noted.

This story was translated from Univadis Italy.