EUGENE, Ore. -- As a former University of Oregon and National Football League quarterback, Chris Miller knows his X's and O's.

But the South Eugene High School football coach also knows his EndoCre3, and he has brought that knowledge to his squad.

Miller, the head coach since 2002, said up to 18 of his players use EndoCre3, a creatine-based supplement made by his Eugene-based company, Body Building Supplements.

"All kids are looking for an edge," Miller told the Eugene Register-Guard. "It's all about getting an edge, no matter what level you're at."

Creatine is an amino acid -- a building block of protein produced naturally by the body and can be obtained by eating meat or fish. When athletes supplement their diets with creatine, they allow their bodies to store more creatine in muscles, which allows them to expend more energy during exercise.

Creatine started catching on as a way to boost athletic performance in the early 1990s. Its popularity boomed in 1998, when the St. Louis Cardinals' Mark McGwire was chasing the single-season home run record and reporters started asking the slugger about the jars of supplements in his locker.

Dave Hancock, the athletic director at South Eugene, said he knew about Miller's ownership interests, but didn't know he sold a creatine product to his players.

"If it's not on the banned-substances list and there's nothing illegal about it, how can you address an individual and say you can't sell it to our kids?" he said.

The National Federation of State High School Associations in Indianapolis strongly discourages the use of supplements. Jerry Diehl, assistant director of the national group, said a coach selling supplements to his players represents a conflict of interest.

"He's making money off his own students," he said. "You've got a closed shop right there where you can influence kids. ... Kids look up to their coaches."

Tom Welter, executive director of the Oregon School Activities Association, also disapproves of the situation.

"The coach is there to guide young people and to coach them in the X's and O's. I don't think their role includes any kind of use of any kind of medications or food supplements," Welter said. "That's a role a health professional needs to be involved in."

Miller said if high school players are going to use creatine, he wants to make sure they get the proper information and use a reputable product.

"I would rather them take something that is better for them, that is natural, than go take some crap," Miller said.

Miller gives players a price break on EndoCre3, but he wouldn't say how much. A 315-gram tub of the powder -- about a month's worth -- sells for $49.95 on the BBS Web site, but other sites sell it for as little as $29.95.

Andrew Downes, the quarterback, said he felt no pressure to use the product: "It was something I wanted to do. I felt like it was worth trying to see if the hype about it was true."

Miller told the paper he talks to parents of his football players about creatine at a preseason meeting, but doesn't require written permission.

Ron Faunce, father of senior wide receiver Nick Faunce, said he talked to Miller and a nutritional specialist and did his own research on the Internet before deciding it was OK for his son to take EndoCre3.

But Tim Stokes, a former NFL player and father of senior tight end John Stokes, said it's "crazy" to take creatine.

"I don't think it's natural and I don't think it's good."