LOUISVILLE, Ky. -- Bulging muscles, seemingly inflatable heads, acne in places that would make a teenager blush, a spike in athletic performance sure to raise eyebrows.
The signs of steroid use in humans can sometimes be easy to detect even without a blood test.
In 1,200-pound thoroughbred horses, the indications aren't so clear.
Though Hall of Fame trainer Jack Van Berg compared horse training to "chemical warfare" during a Congressional hearing on the state of the industry last week, there's little scientific proof that links anabolic steroids to better, stronger, faster horses.
"It's an impossible question for us to even answer," said Dr. Scot Waterman, executive director of the Racing Medication and Testing Consortium. "A .01 (percent) change in performance would alter the outcome of a 1-mile race 50 percent of the time. That is an impossible change to measure with scientific study."
The anecdotal evidence, however, is growing.
Trainer Rick Dutrow caused a stir during the Triple Crown season when he admitted all of his horses -- including Kentucky Derby and Preakness winner Big Brown -- receive monthly doses of the anabolic steroid stanozolol. The drug, sold under the brand name Winstrol, is not banned in the three states where the Triple Crown is run.
In a letter to Congress, Dutrow explained that he has veterinarians administer the drug because it brightens his horses' coats, increases their appetites and makes them train better.
Yet Dutrow felt compelled to have Big Brown skip his monthly steroid dose during the five weeks between the Kentucky Derby and the Belmont Stakes because he felt the horse was "a picture" of health.
The colt certainly didn't race that way. Sluggish from the start, Big Brown was eased by jockey Kent Desormeaux in the final turn at the Belmont on his way to a last-place finish.
With no visible signs of problems other than stifling heat and an acrylic patch on the horse's cracked front left hoof that Dutrow said was not a factor, the result led to questions on the role a lack of steroids might have played in Big Brown's poor performance.
"Everybody is trying to figure out why Big Brown didn't run," said Dr. Don Catlin, president of the Anti-Doping Research Institute. "I don't know why. But I do know if I'm on steroids and if you stop them a couple of weeks ago, I'm going through withdrawal and I'm not going to feel like running. But you can't test for that."
Catlin would know. He's spent the last 25 years leading the charge against drugs in sports and has worked with several organizations, including the NFL and the NCAA, in developing drug-testing procedures.
He served as an adviser to horse racing officials, helping the Racing Medication and Testing Consortium develop rules it hopes the 38 states where racing is conducted will use to implement drug testing. Ten states have already adopted the standards and the National Thoroughbred Racing Association expects the remaining 28 to get on board by the end of the year.
Waterman bristles when asked to compare Big Brown to former sprinter Ben Johnson, who was stripped of his gold medal in the 100 meters at the 1988 Summer Olympics after testing positive for stanozolol.
"(Johnson) was on a cycle, Big Brown was getting one shot a month," Waterman said. "It's completely different and the results are going to be completely different because of it. The infamous Ben Johnson deltoids, you're not going to get that from a once-a-month shot."
Maybe, but in the post-Mitchell Report sports world, having a leading trainer admit he gives his horses steroids doesn't sit well.
"Why give steroids to a horse once a month?" said equine veterinarian Doug Byars. "Do you give it to them because of appetite? No. You give it because you think they may improve their overall performance and keep them at the top of their game."
How much does running on steroids tilt the playing field? A 2007 study by veterinarians at Oklahoma State University on steroids' ability to make horses perform better was inconclusive.
"Despite much anecdotal support of the benefit of anabolic steroid use in equine athletes, there is little scientific evidence with which to corroborate it, and there is little evidence that anabolic steroid treatment offers an advantage in equine athletic performance," wrote author S.C. Pitts.
Rick Arthur, the equine medical director for the California Horse Racing Board, said the inconsistent results have made him skeptical about the benefits of running on the drugs.
"Frankly I don't think they do (help)," Arthur said. "Knowing trainers, if it made that big of a difference, 100 percent of the horses would be running on it."
While it's difficult to point to drastic improvements in on-track performance due to steroids -- Secretariat's track record in the Kentucky Derby still stands 35 years later -- there are numbers that indicate a troubling byproduct of steroid use.
The number of starts for thoroughbreds has dropped from 11.31 in 1960 to 6.37 in 2006, according to The Jockey Club. The rise in the use of steroids and other medications like Lasix and the decline of starts per year is no coincidence said Richard Shapiro, chairman of the California Horse Racing Board.
"You see a direct correlation," he said. "The root of the problem today is medication. As medications are used in the breed and being bred into the breed, they're masking infirmities."
More stringent testing rules proposed by the Racing Medication and Testing Consortium would allow for horses to continue to be given doses of four steroids, including stanozolol.
But horses won't be allowed to race for at least 30 days after receiving the dosage, at which point Waterman said any performance-enhancing effect will be "long gone."
Horses whose steroid levels test above the legal threshold upon their return to the track would have their performances vacated, with the trainer being fined a minimum of $500 and the owner required to return the purse for a first offense.
Subsequent violations would result in stricter penalties under the proposed guidelines, though states would be free to adjust the penalties as they see fit.