The chemist responsible for making "The Clear" says he is certain San Francisco Giants slugger Barry Bonds used his designer steroid to fuel his pursuit of baseball's home run record.

In an interview on the HBO Sports program Costas Now —  highlights of which were published Wednesday by the New York Times —  Patrick Arnold also said he believes Detroit Tigers outfielder Gary Sheffield used performance-enhancing substances.

Clear creator Patrick Arnold believes Barry Bonds used his infamous drug.
(M. Spencer Green/Associated Press)

Both players have denied using drugs.

Arnold, who's credited with creating "The Clear," a previously undetectable steroid that helped athletes build additional muscle mass and recover more quickly after heavy workouts, said he believes the drug was a key component of the "program" the Bay Area Laboratory Co-operative developed for Bonds and Sheffield.

BALCO founder Victor Conte denied he gave Bonds steroids, in a statement issued Tuesday.

"The program I created for Barry was a comprehensive nutritional supplementation regimen and had nothing to do with "The Clear" or any other anabolic steroids," Conte said.

Bonds has hit 753 career home runs, just two shy of Hank Aaron's all-time record.

Arnold told host Bob Costas he planned to watch Bonds break the record on television, according to the Times.

"I feel like in a crazy way, obviously, I'm a part of it," Arnold said. "I, how can I want to miss, how would I miss that?"

In 2006, Arnold pleaded guilty to conspiring to distribute steroids, and was sentenced to three months in prison and three months of home confinement.

He was among five people convicted in the case.

As part of his plea agreement, Arnold did not have to name athletes and coaches to whom he supplied drugs.

But he did testify that he made steroids between June 2000 and September 2003 and gave them to Conte for distribution to athletes in the National Football League, baseball and track and field.

Conte also pleaded guilty to distributing steroids and spent four months in jail before being released in March 2006.

With files from the Associated press