Unlike most “is he on steroids” questions, this one has a definitive answer, and it came from McGwire himself. On 11 January 2010, in an interview with Bob Costas, he admitted using steroids on and off for roughly a decade — including during the 1998 season in which he hit 70 home runs and broke a record that had stood since 1961.
His words were: “I wish I had never touched steroids. It was foolish and it was a mistake. I truly apologize.”
So the answer is yes, by his own account. What is more interesting is the twelve-year gap between the first questions and that admission, and what the whole episode says about reading physiques and performance.
The timeline
1998 — the androstenedione story. Associated Press writer Steve Wilstein reported a bottle of androstenedione in McGwire’s locker, and McGwire acknowledged taking it. Andro was an over-the-counter product already banned by the NFL and the International Olympic Committee, but it was not prohibited by Major League Baseball at the time, and it was not federally classified as an anabolic steroid in the United States until 2004. At that moment he had broken no rule.
1998 — the record. He finished the season with 70 home runs, passing Roger Maris’s 61 from 1961. Barry Bonds broke that mark three years later with 73.
2005 — the hearing. Jose Canseco’s book Juiced claimed McGwire had used performance-enhancing drugs since the 1980s and that Canseco had injected him personally. McGwire was subpoenaed and testified before the House Government Reform Committee on 17 March 2005, where he declined to answer questions under oath, saying his lawyers had advised he could not answer without jeopardising his friends, his family and himself.
2010 — the admission. Five years later, on the eve of returning to baseball as a hitting coach, he told Costas the truth.
What he actually admitted, and what he didn’t
He admitted use across roughly a decade of his career, including the record season. He did not accept that the drugs were responsible for the home runs — his position was that they helped him stay healthy and on the field rather than that they created the power.
That claim is contested and probably unresolvable. What can be said is that staying available matters enormously in baseball. McGwire missed large parts of the early 1990s to injury. Anabolic steroids do assist recovery and connective tissue repair, so “it kept me on the field” and “it improved my numbers” are not really separable arguments.
The andro distinction that still confuses people
A lot of the confusion around 1998 comes from treating androstenedione and anabolic steroids as the same thing. They aren’t quite.
Androstenedione is a prohormone — a precursor the body converts into testosterone. It is far weaker than injectable anabolic steroids, and in 1998 it sat in a legal grey zone: sold over the counter in the United States, banned by several sports bodies, permitted by MLB. The 2004 Anabolic Steroid Control Act reclassified it.
So the andro story and the steroid admission are two separate events, twelve years apart. Reporting in 1998 was about a legal supplement. The 2010 admission was about anabolic steroids.
Why people search for the before-and-after photos
The most common related search is some version of “Mark McGwire before and after steroids,” and what people are really asking is whether you can see it.
Sometimes, in cases this extreme, the pattern is visible. He entered the league in 1986 as a tall, relatively lean first baseman and finished the 1990s carrying substantially more mass. But photographs alone never prove anything, because the same decade included professional strength coaching, a full-time training budget, and simply getting older and heavier as most men do between 22 and 35.
The reason we know about McGwire is not that people looked at pictures. It is that he said so.
What the episode is actually worth taking from it
Three things, if you are researching compounds yourself.
The recovery argument was the honest part of his defence, and it is the effect most consistently reported in the literature — not that these compounds manufacture ability, but that they shorten the time between hard efforts. That is also why they carry risk: the limiting factor they remove is sometimes there for a reason.
Second, the regulatory ground moves. Andro was legal, then it wasn’t. Assume the rules around anything you are looking at can change.
Third, and least comfortable for a site like ours to print: the man who did it said he wished he hadn’t. That is part of the record too, and anyone weighing this decision should have it in front of them.
If you want the practical side, our guide to what is available in Canada covers the common compounds and what each actually does, and there is more background on the blog.
This article reports publicly documented statements and events. Nothing here is medical advice.
