Anabolic Hormones during Bodybuilding Contest Prep

Contest Prep, Tesosterone, IGF-1, and Insulin

One of the beliefs of bodybuilding contest prep is that testosterone drops dramatically as you near your contest (speaking of natural bodybuilders).  Some suggest it’s more of an energy issue.  Meaning your simply to tired to be interested in things like sex.  Others believe the lack of bodyfat, and or fat consumption lead to lower testosterone levels and thus a lower libido.  Unfortunately there isn’t a whole lot of science on what really happens.

More recently a case study was completed by researchers like Jeremy Loenneke at the University of Oklahoma that followed a high level natural bodybuilder over the course of his contest prep, and the 6 months post contest [1].  This case study has been discussed quite heavily in the bodybuilding news world, but in general they found drastic decreases in body fat, resting heart rate, and blood pressure over the course of his contest prep.  They also found that testosterone decreased 9.22 ng/mL to 2.27 ng/mL over the contest prep period, which represents a 75% decrease in testosterone.  That’s pretty significant as you can tell, however as with any case study, the population sample doesn’t necessarily prove that testosterone drops during contest prep.

If we want a bigger sample size, we need to go back to a rarely discussed study conducted on 14 amateur male bodybuilders [2].    In this study they specifically wanted to find out how contest prep affected anabolic and catabolic hormones.  They split them into two groups.  The control group was instructed to maintain the same food intake, and training volume throughout the 11-week study.   While the Contest Prep group was allowed to diet and train as they wished, but only with the intention that they would compete in the European National Championships at the end of the 11 weeks.  I should note the contest prep group was natural, or at least they were self reported natural, and had shown proof they had not failed any drug tests from previous shows, and they also did not fail a drug test at the national championships (at the end of the study).

LeanBulk-logvector-blackTraining Results

While the study was not designed to compare training regimens, it’s still worth looking at.  The Contest Prep group had a much higher training volume over the course of 11 weeks.  That’s not surprising since they were in contest prep, but what was interesting was that the training protocol was simply an increase in aerobic activity over the 11-week period.  At the start of the study (Week 11) the Contest Prep group was doing the following each week:

  1. 600 minutes of total training (10 hours per week)
  2. 5.5 Hours of Weight Training

By the end of the study (3 days before they stepped on stage), they were completing the following amount of training each week:

  1. 825 minutes of total training (13.75 hours per week, or about 2 hours per day)
  2. 5.4 Hours of Weight Training

As you can see, their cardio increased significantly, but they didn’t weight train any more at 3 days out then they did at 11 weeks out.  It’s worth mentioning that that total training volume peaked at week 10, where they were spending about 2.4 hours per day in the gym.  Meanwhile the control group spent about 1 hour in the gym each day, and of that hour, about 40-45 minutes was spent weight training.

Diet Results

Again, not a study looking about bodybuilder diets, but maybe we can learn something.  The Contest Prep group followed a consistent 28% protein, 60% carbohydrate, and 12% fat over the course of the 11-weeks.  They did note carbohydrates decreased over the prep period, but not significantly.  Over the 11-weeks their total calories decreased 13%, which again is not a huge change.  Their calories started around 3,700 and decreased to 3,235 3 days out.

So their diets didn’t change much, but their cardio volume certainly did.  In the end it resulted in almost a 1,000-calorie deficit 3 days out (total calories minus calculated expenditure).

Anabolic and Catabolic Hormone Changes

This brings us to the purpose of the study.  What exactly happens to anabolic and catabolic hormones during contest prep?  Based on this research they found the following:


  1. Decreased 11.3% from 11-weeks out to 5-weeks out
  2. Decreased 4.4% from 5-weeks out to 3 days out
  3. Decreased 15.2% from 11-weeks out to 3 days out

It’s worth noting their testosterone levels 3 days out were 17.2 nmol/L, or 505 ng/dl.  This is still well within normal ranges (What are normal testosterone levels?).  As you also might notice the testosterone drop was relatively small (15%) compared to the study on one bodybuilder in the University of Oklahoma study.  One might argue they were using anabolic steroids, but not many guys are using doses that only put them in low to normal ranges before a show.  Is 15% a big deal?  It’s possible a 15% drop could reduce your libido, especially as a 25-year-old male.  But most guys would simply not worry about a 15% drop.  This is for the same reasons many are un-interested in testosterone boosters, which typically do nothing more than increase testosterone slightly while improving libido.

Body Composition Changes

  1. Body fat dropped from 9.6% to 6.5% (per DEXA scan)
  2. Total weight dropped 9 lbs on average
  3. Lean Body Mass changes were insignificant (meaning they retained lean body mass)

Nothing particularly ground breaking here.  They lost body fat and retained (a lot of) lean body mass.  Whether or not 6.5% body fat is low enough for a national stage is debatable.  I’ve heard people test as low as 4% body fat pre-contest with DEXA scans.


  1. Decreased Significantly over the 11 week prep
  2. 17.9% Decrease from 11 weeks out to 5 weeks out
  3. 22.9% decrease from 11 weeks out to 3 days out

Based on my brief research, their IGF-1 levels (152 ug/L) at 3 days out are quite low for 25 year old males.


  1. Decreased significantly over the 11-week prep
  2. 33.3% Decrease from 11 weeks out to 5 weeks out
  3. 45.2% decrease from 11 weeks out to 3 days out

Insulin is known to be muscle sparing (anti-catabolic), but it also is inversely related to lipolysis, a critical step to fat loss.  By three days out they were below healthy reference ranges.  The authors note that in these circumstances protein synthesis can be impaired.

“Fedele et al (8) showed that there is a critical concentration of insulin below which rates of protein synthesis begin to decline in vivo and it is possible that a low but critical concentration of insulin must be available for anabolism after exercise.”


What can we learn from this?

The authors do discuss a practical application to these findings.  They suggest eating more protein will not help retain muscle mass in these conditions (low IGF-1, and insulin).  Instead they suggest the ingestion of carbohydrates.  This of course is quite in line with a lot of what we know.  Which put simply is that the leaner you are, the more often you need to have “refeeds”.  And refeeds should not be consuming all the shit food under the sun.  Instead refeed days should maintain your current protein intake, while increasing carbohydrates, and limiting fat.  That means no Mcdonald’s fries, and burgers.


If you wanted to, a natural bodybuilder could incorporate supplements to try and recover IGF-1 levels as they get leaner.  I would suggest taking a look at some of the options our biochemist Androgen discusses in the following article – Natural ways to increase Growth Hormone.

You might also consider using a supplement that falls into the category of a nutrient partitioner or glucose disposal agent (GDA).  You have to be careful with these however, as some act more like carb blockers.  You specifically want one that results in an increase in insulin.  It’s possible a cheap option might be huperzine A, which is a somatostatin inhibitor (somatostatin inhibits pancreatic insulin release).

In the end, the easiest possible solution may be to be diligent with your refeeds.  Time your contest prep properly, and when you do consume carbs late in contest prep, consume them in fewer meals to increase the glycemic load, and stimulate a greater insulin response.


Need a qualified contest prep coach?  Questions on this article?  Shoot me an email, and we will point you in the right direction.


[1]  L. M. Rossow, D. H. Fukuda, C. A. Fahs, J. P. Loenneke, and J. R. Stout, “Natural Bodybuilding Competition Preparation and Recovery: A 12-Month Case Study,” Int J Sports Physiol Perform, Feb. 2013.


[2]       J. Mäestu, A. Eliakim, J. Jürimäe, I. Valter, and T. Jürimäe, “Anabolic and catabolic hormones and energy balance of the male bodybuilders during the preparation for the competition,” J Strength Cond Res, vol. 24, no. 4, pp. 1074–1081, Apr. 2010.