Barry Bonds started taking steroids around the end of the 1998 season. According to reports, he began with Winstrol, a steroid used by other athletes, after the 1998 season. His use of performance-enhancing drugs, including steroids and human growth hormone, continued for at least five seasons beginning in 1998. By 2001, he was allegedly using designer steroids known as "the Cream" and "the Clear," along with other substances like insulin and testosterone decanoate. Bonds' steroid regimen became more sophisticated over the years, and 2001 was also the year he broke the single-season home run record with 73 home runs.
Additional testimony and investigations related to the BALCO scandal confirm that Bonds was involved in steroid use during the early 2000s, though he initially denied knowingly using banned substances, claiming he thought they were nutritional supplements. Testimony from witnesses and leaked grand jury testimony later suggested otherwise.
In summary, Barry Bonds started using steroids seriously in the period starting in 1998.
