As a personal trainer and a judge for National Physique Committee bodybuilding events, Dr. Bruce Nadler has seen his share of bulging biceps, massive pecs and delts that might make a Greek god hang his head in shame.
But he said that what he has seen on the professional bodybuilding circuit in recent years takes the cake.
"When I go to the bodybuilding performances now, some of them, their appearance is barely human," he said.
So what's behind the 30-inch biceps and the other freakishly proportioned muscle groups on display nowadays?
The culprit is a type of injectable oil, commonly known as synthol.
Bodybuilder and fitness author Ron Harris said that synthol and products like it are used only by "a very small percentage of bodybuilders, but they tend to really stand out."
"They are just obnoxious to behold," he said.
And Nadler said that the practice has gotten way out of hand.
"There are some instances of absolutely freakish appearance because of it," he said. "The fact that a lot of individuals have this bizarre appearance shows that there is an attraction there, even if it is the same type of attraction you'd see at a bad car wreck."
A Growing Trend
Invented in the mid-1990s by a German bodybuilder named Chris Clark, synthol is a thick oil that is usually injected directly into the "belly" of a muscle to literally pump it up -- albeit temporarily.
Competitive bodybuilders originally used synthol and other products like it, known collectively as site enhancement oils, to even out minor asymmetries in muscle size and shape.
But before long, some bodybuilders began injecting massive quantities of the oil into their arms in order to appear more buff -- a practice known in the sport as "fluffing."
"It makes the muscle appear larger, but it actually weakens it," said Dr. Mauro DiPasquale, a former bodybuilder and physician in Ontario, Canada, and president of the United World Powerlifting Federation.
In this way, synthol is not the same as steroids. While steroids are hormones that help increase the actual muscle size and mass, synthol is a bit like an implant for the arms; it just makes muscle look bigger.
However, Harris said, "The same mentality that would drive people to use steroids would drive them to this."
But in bodybuilding, being artificial isn't always perceived as a bad thing. As a former cosmetic surgeon whose services were sought out by a number of bodybuilders, Nadler said he has used medical aesthetic procedures to help some patients increase the apparent size of certain muscles -- from calf implants to pectoral implants.
But he said that in most cases the abuse of synthol leaves much to be desired in terms of appearance.
"It is used and abused today in everything from filling muscles to making muscles look like big bags of oil," he said.
Harris agrees. "You get weird lumps and bumps, as well as an almost bizarre shape to the muscle."
That doesn't deter some competitive bodybuilders, who see the shots as a shortcut to massive gains.
"I've heard of one person who had 150 synthol injections into one muscle area," DiPasquale said. "I've seen people who have tried to pump their 19-inch arms up to 22-inch arms."
Buying Bigger Muscles Online
Thanks to the Internet, site enhancement oils (and the syringes used to inject them) are widely available to professional bodybuilders and weekend warriors alike.
Marketed as a "posing oil," a single bottle of synthol and products like it can run between $200 and $400.
"You can buy it online and get it shipped right to your house," Harris said. "Either the FDA has too much going on to pay attention to it, or they really don't know how it's being used.
"If it was actually marketed for its true use, then you would see much more backlash against it."
Telephone messages left with distributors of two such products -- Syntherol and PumpNPose -- were not returned.
Risks of Pumping Up
Even though it is not currently regulated, some worry that bodybuilders could be putting their health at risk.
"A couple of years ago, there was a case of someone injecting synthol accidentally into a small artery, and he actually killed off part of his muscle," DiPasquale said. "And with any injection, if it is close enough to the nerve, it will disrupt that as well."
Harris agrees, noting that he has read a few reports of people who have used site enhancement oils who have nearly died from complications associated with the injections. And Nadler said that there is a possibility that a user could inject it into a blood vessel, causing a potentially life-threatening embolism.
"I'm sure there has to have been some human deaths because of this," he said.
DiPasquale said that unsterilized needles can also lead to abscesses and infections, as well as the formation of scar tissue.
But he adds that despite the risks, many will still use the product if it means an extra couple of inches on their arms.
"I really don't advise people to use synthol," he said. "It is not something that is recommended, but if someone is going to do it, they're going to do it."
Freak Show Bodies Not for Everyone
Not all bodybuilders approve of synthol use; in fact, even in this sport where many look to enhancement through pharmaceutical means, synthol abusers are viewed as cheaters.
"Even the ones who use steroids and those who don't are vehemently against synthol use," Harris said. He adds that while steroid users still must eat right and train in order to reap gains, those who use synthol are perceived as taking the ultimate shortcut toward a more massive appearance.
"Even among a group where pretty much anything goes in terms of pharmaceutical use and abuse, even to them this is a scourge," he said. "It's cheating; there's no effort involved."
But Nadler said that though he does not feel the trend represents the bodybuilding community as a whole, he fears those that abuse site enhancing oils are setting a bad example for adolescents and teens interested in bodybuilding.
"I don't think the bodybuilding community has come out strongly enough condemning this sort of freakish appearance," he said.
"It's part of the almost kind of shortcut thinking that goes on with a lot of what's happening in bodybuilding, whether it's abusing steroids or some other substance."
Still, Harris said, the stigma of synthol abuse could be enough to keep many bodybuilders away from the bottle and the needle.
"They really have no allies. They're mocked online on our message boards by other bodybuilders," he said.
"I honestly don't know if some of those guys are not all there, but they're not fooling anybody."