At the 1992 Olympics in Barcelona, British athletes began using creatine, a natural compound that boosts muscle energy and performance. Unlike banned substances, creatine was legal and allowed under doping rules. It became a popular supplement for athletes, despite initial skepticism about its use. Today, supplements are a common part of elite training, helping with muscle development, strength, and addressing nutritional gaps. According to Prof Graeme Close, a physiology expert at Liverpool John Moores University, up to 90% of athletes may use supplements, with some teams reporting nearly universal usage. Creatine is naturally produced in the body by the kidneys, liver, and pancreas. It helps muscles generate energy quickly, which is especially useful for high-intensity, short-duration activities like sprinting. In the 1990s, research on creatine was shared with Steve Jennings, who supplied supplements to the British Olympic team. Investigative journalist Doug Gillon noted that if creatine's potential to improve explosive performance by 1-3% was confirmed, it could significantly alter the landscape of competitive sports. By the 1996 Olympics, an estimated 80% of athletes were using creatine, and it has since become a mainstream supplement, with studies even suggesting possible cognitive benefits. The global dietary supplements market was valued at $209.5 billion in 2025 and is expected to grow to $431.7 billion by 2033. Close, who has worked with elite sports teams, considers supplements an essential part of an athlete's nutrition plan, though he emphasizes that most performance benefits come from a balanced diet. Australian cyclist Nicole Frain agrees, noting that supplements should complement—not replace—proper nutrition, training, recovery, and hydration. Common supplements include protein powders, creatine, and vitamin D, each serving specific roles in muscle repair, energy provision, and overall health. While supplements can enhance performance, the term "performance-enhancing" often raises concerns about doping. The World Anti-Doping Agency (Wada) evaluates substances based on health risks, performance impact, and whether they violate the spirit of sport. Creatine is not banned, as it is not harmful and aligns with the spirit of sport. However, athletes must remain cautious, as unintentional use of prohibited substances can lead to disqualification. Programs like Informed Sport aim to ensure supplements are free from banned ingredients, but Wada notes these programs reduce—not eliminate—the risk of violations. Some athletes, like British rower Heidi Long, use detailed tracking systems to monitor supplement safety, while others, like Close, visit manufacturing sites to verify quality. Some athletes prefer a "food-first" approach, relying on whole foods for nutrition. Ingredients like turmeric, pickle juice, beetroot, and an ancient Ethiopian grain called teff—rich in minerals and protein—are gaining attention for their potential benefits. British boxer Fran Hennessy credits teff with improving her performance and recovery. Cost and taste also influence supplement choices. While some athletes invest in supplements during critical competitions, others prefer obtaining nutrients through food, enjoying meals over the sometimes unpalatable gels and powders used during training.