Michellefretz
New member
A new study by researchers in the US found that contrary to what many people may assume, scientific evidence does not support claims that human growth hormone (HGH) increases strength or athletic performance.
Liu and colleagues reviewed randomized controlled trials comparing HGH with non-HGH treatment in physically fit, healthy people aged 13 to 45 and found that while growth hormone increased lean body mass it did not increase strength and the capacity to exercise.
They also found that people who took GH had more frequent tissue swelling and experienced fatigue more often than people who did not take the substance.
The researchers concluded that the available scientific evidence does not support claims that GH improves physical performance. In fact while lean body mass may increase, strength does not and GH may even diminish exercise capacity and lead to other adverse side effects.
The safety and effectiveness of HGH is poorly understood, even though it is reportedly used to enhance athletic performance, said Liu and colleagues in their background to the study.
They decided to investigate all the published randomized controlled trials they could find that compared HGH with non-HGH treatments in healthy community dwelling people between 13 and 45 years of age. They searched a number of databases and found 44 articles of which 27 met their inclusion criteria.
When pooled together, the results showed that:
• 303 participants received HGH, equivalent to 13.3 person-years of treatment.
• The participants were young (mean age was 27 years), lean (mean BMI of 24), and physically fit (maximum O2 uptake was 51 mL per kilo of bodyweight per min).
• HGH dosage (mean of 36 micrograms per kg per day) and treatment duration (mean of 20 days) for studies where participants took HGH for more than a day varied.
• Lean body mass went up in participants taking HGH compared with those who did not (increase 2.1 kg, range 1.3 to 2.9), but strength and exercise capacity did not appear to increase.
• Lactate levels during exercise were significantly higher in 2 of the 3 studies that measured them.
• Participants who took HGH had soft tissue edema (swelling) and fatigue more often than non-HGH participants.
Liu and colleagues concluded that:
"Claims that growth hormone enhances physical performance are not supported by the scientific literature."
"Although the limited available evidence suggests that growth hormone increases lean body mass, it may not improve strength; in addition, it may worsen exercise capacity and increase adverse events.
Liu and colleagues reviewed randomized controlled trials comparing HGH with non-HGH treatment in physically fit, healthy people aged 13 to 45 and found that while growth hormone increased lean body mass it did not increase strength and the capacity to exercise.
They also found that people who took GH had more frequent tissue swelling and experienced fatigue more often than people who did not take the substance.
The researchers concluded that the available scientific evidence does not support claims that GH improves physical performance. In fact while lean body mass may increase, strength does not and GH may even diminish exercise capacity and lead to other adverse side effects.
The safety and effectiveness of HGH is poorly understood, even though it is reportedly used to enhance athletic performance, said Liu and colleagues in their background to the study.
They decided to investigate all the published randomized controlled trials they could find that compared HGH with non-HGH treatments in healthy community dwelling people between 13 and 45 years of age. They searched a number of databases and found 44 articles of which 27 met their inclusion criteria.
When pooled together, the results showed that:
• 303 participants received HGH, equivalent to 13.3 person-years of treatment.
• The participants were young (mean age was 27 years), lean (mean BMI of 24), and physically fit (maximum O2 uptake was 51 mL per kilo of bodyweight per min).
• HGH dosage (mean of 36 micrograms per kg per day) and treatment duration (mean of 20 days) for studies where participants took HGH for more than a day varied.
• Lean body mass went up in participants taking HGH compared with those who did not (increase 2.1 kg, range 1.3 to 2.9), but strength and exercise capacity did not appear to increase.
• Lactate levels during exercise were significantly higher in 2 of the 3 studies that measured them.
• Participants who took HGH had soft tissue edema (swelling) and fatigue more often than non-HGH participants.
Liu and colleagues concluded that:
"Claims that growth hormone enhances physical performance are not supported by the scientific literature."
"Although the limited available evidence suggests that growth hormone increases lean body mass, it may not improve strength; in addition, it may worsen exercise capacity and increase adverse events.
