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15.05.2010


Lifting weights? BCAAs plus glutamine may raise your testosterone levels

Strength athletes produce more testosterone, and less cortisol, if they take a handful of caps containing BCAAs plus glutamine every day, write researchers from Ball State University in the Journal of Strength and Conditioning Research.

Study
BCAAs plus glutamine raise testosterone levels in bodybuilders
One of strength athletes' biggest enemy is too much stress. We're talking physical stress here: training causes big-time stress in the form of continuous damage to muscle tissue. And the body reacts to this by increasing its production of the muscle-destroying hormone cortisol and reducing its production of testosterone. So could you do something about this by providing the muscles with the amino acids they need most? That's what the researchers wondered. So they gave 8 recreational lifters who by the way hadn't been in a gym for six months a daily 3 g BCAAs and 2 g glutamine for a period of 4 weeks.

The preparation that the researchers used was Nutri-Build II, a Nutrient Technologies product. Nutrient Technologies helped finance the study. The researchers had their test subjects take 6 caps at breakfast and with their evening meal. The subjects took a daily total of 2 g L-glutamine, 1800 mg L-leucine, 750 mg L-isoleucine and 750 mg L-valine.

In the fourth week the subjects trained, 4 times. They exercised all main muscle groups, doing leg presses, leg curls, leg extensions, chest presses, military presses, lat pulldowns, dumbbell curls and triceps pushdowns.

A couple of weeks later the researchers repeated the procedure, but gave the subjects a placebo.

Results
When the researchers measured the athletes' cortisol level 12 hours after training, they noticed that it was lower when the athletes had taken the amino acids. When the athletes had been given a placebo, their cortisol levels went up.


BCAAs plus glutamine raise testosterone levels in bodybuilders


The testosterone level reacted in exactly the opposite way. It rose when the athletes took BCAA.


BCAAs plus glutamine raise testosterone levels in bodybuilders


Researchers look at the cortisol:testotesrone ratio when they want to determine whether a body is an anabolic environment. The higher the ratio, the more muscle you should be able to build up. The figure below shows the effect of BCAA plus glutamine on the C:T ratio.


BCAAs plus glutamine raise testosterone levels in bodybuilders


Whether the athletes built up more muscle because they took the amino acids the researchers did not determine. What they did see is that creatine kinase concentration rose by less when the athletes used BCAAs and glutamine. Creatine kinase is an indicator of muscle damage. The figure below is based on the measurements that the researchers took 12 hours after the training sessions.


BCAAs plus glutamine raise testosterone levels in bodybuilders


Conclusion
As in so many studies financed by industry, there are problems with this research. "Subjects with a dietary protein intake in excess of the recommended daily allowance (0.8 g/kg/day) were excluded from the study", the researchers write, describing how they selected their test subjects. This protein intake level is pretty low for a strength athlete, but later in the article we learn that the intake was actually even lower. "In the present study, dietary analysis showed that no subjects were consuming more than 0.7 g/kg per day of protein during the course of the study." No doubt the amino acids had an effect.

But the study is not enough to convince us of the worth of using amino acids. What it does convince us of, though, is that strength athletes need to make sure you eat enough protein.

Source:
J Strength Cond Res. 2010 Apr; 24 (4): 1125-30.