Most athletes understand the important role growth hormone (GH) plays in building strength, muscle mass, and increasing performance. Growth hormone not only stimulates an increase in muscle protein synthesis, but it also stimulates joint cartilage production, amino acid uptake by cells and the use of fat for fuel. To get the best results from training, you have to make sure your natural production of growth hormone is at its peak.
However, most athletes don’t know that growth hormone circulates in multiple molecular forms, only some of which are biologically active. That is, only a small fraction of the growth hormone your body produces actually exerts the biological effects you are after.
Firstly, there is the intact immune-reactive form of growth hormone (irGH). This form of growth hormone possesses two separate receptor-binding domains, both of which are necessary to engage the growth hormone receptor and initiate a cellular response. The immuno-functional GH (ifGH) represents the fraction of irGH that contains these all-important binding domains; this is the fraction of GH that is biologically active.
In men, the bulk of bioactive GH (ifGH) secretion occurs at night. However, studies show that daytime production appears to be comparatively low. Therefore, if we have a way to boost the level of bioactive GH during the day, it may provide faster muscle growth and more effective fat loss.
Studies in the past have shown that both intense aerobic and resistance exercise stimulate GH secretion. The problem is, scientists are not sure how much of this GH is the bioactive form. The good news is, a new study has shown how you can jack your bioactive GH levels every time you train.1
GABA and Growth Hormone
In this study, 11 healthy, resistance-trained males participated in four experimental trials; two resting and two exercising. The bouts of exercise were short, fairly intense weight lifting workouts. Each trial was separated by one week. Just before each trial began, the men were given 3 grams of GABA or a placebo. Blood samples were taken up to 90 minutes after the dose. The samples were analyzed for ifGH, (the bioactive form of GH).
GABA (Gamma Aminobutyric Acid), is an amino acid classified as a neurotransmitter. As a supplement, GABA has been shown in clinical trials to be remarkably consistent at elevating blood GH levels. In some cases by over 500%! However, even though GABA is an effective GH-booster and, intense exercise also spikes GH production during the day, no studies had examined the combined effect of taking GABA before an intense bout of exercise such as weight training.
The results of this new study were quite interesting, to say the least!
Here’s what the results showed.
- At rest, a 3-gram dose of GABA elevated both GH and ifGH compared with placebo. Specifically, peak concentrations of both hormones were elevated consistently, 375% above normal levels. That’s a consistent 375% in bioactive GH simply from taking GABA.
- Weight training elevated both GH and its bioactive form significantly. However, the combination of GABA supplementation and weight training elevated both GH and ifGH concentrations around 175% greater than exercise alone.
- So, exercise boosts the production of bioactive GH but taking GABA before exercise enhances this response, greatly.
- GABA ingestion did not alter the ratio of bioactive ifGH to regular GH under all study conditions. Interestingly, ifGH represents approximately half (50%) of the irGH fraction.
- Probably the most important aspect of this study was the level of control and therefore, the quality of data. This study was double-blind, randomized and a crossover design. This means no one directly involved in the study knew who was getting what, and every participant was assessed under all 4 conditions; at rest (a dose of GABA and placebo) and exercise (after a dose of GABA and the placebo). These procedures ensure that the data obtained is about as good as it gets.
What This Research Means to You
Clearly, a dose of GABA is very effective at boosting the production of bioactive growth hormone, particularly during the day – a time when growth hormone production is usually low. GABA can be used to boost the natural production of GH during the day, but most importantly, the bioactive form of GH will also be increased.
Secondly, whenever you hit the gym and train with high-intensity, you can be assured of a nice, training-induced spike in bioactive growth hormone. However, if you want to crank it up a notch or two, take a dose of GABA before each workout. The results of this study show you will experience a significantly greater increase in bioactive GH than from just exercise alone.
One final thing. In this study, the subjects were given the supplement first thing in the morning, on an empty stomach. Therefore, to ensure the best GH response, if you train in the morning, I recommend you take your dose of GABA first thing, as soon as you wake up. That way, when you hit the gym for your morning workout, you can be assured of an optimum GH response from training.
Source: Powers ME, Yarrow JF, McCoy SC, Borst SE. Growth hormone isoform responses to GABA ingestion at rest and after exercise. Med Sci Sports Exerc. 40, 104-10, 2008.
