The percentage of teens who admit to using hGH jumped to 11 percent in 2013 -- more than double the 5 percent figure in 2012, the new survey from the Partnership for Drug-Free Kids revealed.
The worrisome trend highlights a need for tighter regulation and oversight of performance-enhancing substances and other "fitness" products, the group said.
"These new data point to a troubling development among today's teens," Steve Pasierb, president of the Partnership said in a group news release. "Young people are seeking out and using performance-enhancing substances like synthetic hGH -- and supplements purporting to contain hGH -- hoping to improve athletic performance or body appearance without really knowing what substances they are putting into their bodies."
Another expert agreed the new data is troubling.
"The marked increase in teens' reported use of performance-enhancing substances such as steroids or synthetic growth hormones over just the last few years cries out for a massive public health campaign to educate them about the catastrophic -- and even fatal -- potential risks of misusing such products," said Dr. Patricia Vuguin, a pediatric endocrinologist at Cohen Children's Medical Center in New Hyde Park, N.Y.
The body produces human growth hormone naturally, and experts have long known that the hormone is essential for growth and cell production in young people. It also helps regulate body composition, muscle and bone growth.
A synthetic form of this hormone, known as hGH, has been available since 1985, the Partnership noted. Congress has approved certain uses of synthetic hGH, such as for muscle-wasting disease associated with HIV/AIDS, adult deficiency due to rare pituitary tumors and the long-term treatment of short stature in children.
Any off-label use of hGH for other medical conditions is strictly prohibited, however.
People hoping to boost their athletic abilities or enhance their appearance have abused synthetic growth hormone in the past. In order to track the use of hGH and other performance-enhancing substances, the researchers surveyed more than 3,700 high school students. They also questioned 750 parents during in-home interviews.
Although gender did not significantly affect use of synthetic hGH, the study found race and ethnicity did play a role. Black and Hispanic young people reported using synthetic hGH at higher rates than white teens. The researchers found that 15 percent of black teens and 13 percent of Hispanics said they used the substance at least once, compared to 9 percent of white teens.
There was also a strong link between use of hGH and steroids, the study showed. Steroid use among teens also rose from 5 percent in 2009 to 7 percent in 2013.
Using synthetic hGH and other performance-enhancing substances and products poses serious health risks, the study authors warned. There is a largely unregulated marketplace, they noted, involving a variety of products promising to boost muscle mass, athletic performance and physical appearance.
"These are not products that assure safety and efficacy," Pasierb said. "Prescription and over-the-counter medicines must go through rigorous testing to be proven safe before being sold to the public, but supplement products appear on store shelves without regulation from the Food and Drug Administration and must actually be proven unsafe before being removed from sale," noted Pasierb.
He said that this "creates a false perception of safety, driving impressionable teens to risk their health with potentially dangerous products that are untested. And while it's doubtful that all of the teens who reported having used synthetic hGH actually obtained prescribed synthetic human growth hormone, the proliferation of commercially available products that are marketed saying they contain synthetic hGH, or promote the natural production of hGH within the body, is staggering."
Teens are also more aware of the online marketing of steroids and synthetic hGH than they were two years ago, and less likely to believe their health is at significant risk by using performance-enhancing drugs, the research revealed.
"Given the current regulatory framework of the supplement industry, and the amount of products being marketed and sold online, it is difficult if not impossible to know what exactly is contained in these products teens are consuming," Pasierb added.
"So the implication for parents, health care professionals, policy makers and regulators is that this is an area of apparently growing interest, involvement and potential danger to teens that calls for serious evaluation of the areas in which current controls on manufacturing and marketing are failing to prevent the use of these products by teens," he explained.
Young people who do not see these substances as risky are more likely to use them, the study authors cautioned.
The new survey highlights "the need to protect young people from those who would prey on them as easy marketing targets," Travis Tygart, CEO of the U.S. Anti-Doping Agency, said in the Partnership news release.
Although 58 percent of parents said they've talked to their kids about steroids or other performance-enhancing substances, the study revealed that only 3 percent believe their teens have ever used the products. Meanwhile, just 12 percent of teens reported having a discussion with their parents about drugs that included synthetic hGH.
"What I encounter when talking to teens is the significant pressure they feel to excel," Tyler Hamilton, former professional cyclist and anti-doping advocate, said in the news release.
"Whether it's in sports, school, social status or appearance, teens feel they need to be better. The study provides a good opportunity for parents and other influential figures in their lives to realize what teens are facing and reinforce a message of unconditional love and acceptance," added Hamilton, who gave back his Olympic Gold medal after admitting to performance-enhancing drug use throughout his career.
Vuguin had her own theories as to the uptick in use of hGH among teens.
"Steroid use among young males, particularly those who lift weights, has been on the radar for years," she said. "But it's surprising and disturbing to see that teenagers of both genders are increasingly using synthetic versions of human growth hormone, ostensibly to maximize muscle mass and minimize body-fat composition," she added.
"While it's difficult to pinpoint why more teens may be using these substances, I strongly suspect that the rising 'selfie culture' among young people -- who increasingly rely on social media to project their body image -- is influencing these disturbing new statistics," Vuguin said.
In addition to tracking the use of performance-enhancing substances, the study found other trends in teen drug abuse, including:
- Nearly half, or 44 percent, of teens said they've used marijuana at least once in their lifetime. Of these teens, 41 percent started before they reached 15 years of age.
- Roughly one in four teens, or 23 percent, admitted to abusing or misusing a prescription drug at least once.
- The percentage of teens who ever tried using over-the-counter cough medicine to get high jumped from 12 percent in 2012 to 15 percent in 2013.
The U.S. Anti-Doping Agency has more on the effects of performance-enhancing drugs.