Mark McGwire: natty or not?

Confirmed 70 home runs in 1998, the record that saved baseball and then unravelled

Short answer. Verdict: confirmed. At the peak physique on this page, Mark McGwire is 6'5" (196 cm) and 245 lbs (111 kg) at roughly 15% body fat. That works out to an FFMI of 23.6, against the ~25 mark cited as the natural ceiling.

The numbers (estimated)

Note. Playing weight is the listed figure; the body-fat number is an estimate. The verdict below is not — it rests on his own admission. See the methodology page for how we judge.

A photo of Reggie Jackson giving him advice at Comiskey Park on 30 June 1987 has McGwire at 23, in the rookie season the table below opens with.

Mark McGwire admitted it, on camera, with a date range attached. On January 11, 2010 he told Bob Costas: “I wish I had never touched steroids. It was foolish and it was a mistake. I truly apologize. Looking back, I wish I had never played during the steroid era.” He said he used on and off for about a decade, starting in the 1989-90 off-season, again after a 1993 injury, and through the 1990s — including 1998.

1998 is the year that matters. That season he hit 70 home runs and broke a record that had stood since 1961.

Confirmed.

The numbers, and why they are not the point

McGwire is listed at 6’5” (196 cm) and 245 lbs (111 kg). Run that through the FFMI math and the answer is unremarkable — a very big man of normal build reads as ordinary on an index that divides by height squared.

That is the useful lesson on this page. FFMI catches bodybuilders. It does not catch a tall athlete taking steroids for recovery and bat speed, which is what McGwire says he was doing. For an athlete like this, the evidence is the record, not the arithmetic. Here the record is his own confession.

The timeline makes the same point twice. As a rookie in 1987 he was 6-foot-5 and 225 lbs when he hit a rookie-record 49 home runs, against the 245 he is listed at later. That is about 20 lbs across eleven years, and it brackets the period he admits using. Twenty pounds on a 6’5” frame in your twenties and thirties is not, on its own, evidence of anything.

Which is exactly why this page rests on the confession. A reader scanning for a dramatic before-and-after will not find one here, and McGwire used anyway.

The andro footnote

During the 1998 chase, reporters found androstenedione in his locker and he acknowledged taking it. It was legal in baseball at the time, banned by the NFL and the IOC, and not classified as an anabolic steroid under U.S. law until 2004. Andro was never the real story, and his 2010 statement is about the things that were.

Verdict

Confirmed — by admission, twelve years after the record and without a positive test forcing it. What he actually took, and in what amounts, he has never itemized.