You lift hard and heavy. You make sure you get your protein every day and you even keep a food log. You use the right supplements and drugs. In short, you do everything you can to build muscle.

Despite all this, despite the sweat, the commitment, the yearning, you look enviously on all those bastards that seemingly do so many things wrong or haphazardly, yet still carry more muscle that you could ever hope to.

You wonder why God bestowed upon them the abilities we so desperately desired. We wonder if they have superior muscle fiber ratios, optimal testosterone/estrogen balance, exquisite insulin sensitivity, or maybe possess some special, secret way of squatting, deadlifting, or benching. Yet, apparently, no matter how identical your diet, drugs regimen and training routine are compared to theirs, the results are night and day.

Well, according to a fascinating new paper, it's none of that stuff, and if God bestowed upon these muscular bastards some special gift, it's a lot of androgen receptors (ARs).

ARs are the cellular "ignition switches" that, when turned on by androgens (testosterone and all other anabolic steroids ), initiate the process that leads to the production of proteins – the physical building blocks of tissues, and in this case, muscle.

Surprisingly, the authors of a new paper found that the density of these ARs was the most important determinant in putting on muscle and that actual levels of anabolic hormones don't play nearly as important a role.

Morton and his colleagues examined circulating hormones, intramuscular hormones, and intramuscular hormone-related variables in previously trained men before and after 12 weeks of resistance training.

That means they evaluated levels of anabolic hormones like testosterone, free testosterone, dehydroepiandrosterone, dihydrotestosterone (DHT), insulin-like growth factor-1 (IGF-1), free insulin-like growth factor-1, along with changes in resistance-training induced increases in muscle mass.

Based on the results, the men were classified as either high responders (HIR) or low responders (LOR). The number of androgen receptors didn't change during the training, but was higher at all times in the high responder group.

In fact, there was a linear relationship between androgen receptor content and change in lean body mass (muscle). The researchers concluded the following:

"These results indicate that intramuscular androgen receptor content, but neither circulating nor intramuscular hormones (or the enzymes regulating their intramuscular production) influenced skeletal muscle hypertrophy following RET (resistance training) in previously trained men."

The findings of Morton's team appear to explain how hardgainers, despite training exactly like their more successful counterparts, may simply be short on androgen receptors while behemothic lifters have a rich bounty of them.

In fact, the true advantage possessed by pro bodybuilders may be that they're genetically gifted steroid receivers. Because they have more receptors, they probably can grow much, much, bigger than you could, even if you took an equally large boatload of steroids.

This doesn't mean having high anabolic hormone levels in general won't help you, but the hormones can only go as far as the receptor content of your muscles will allow them. After all, if there are only a limited number of "ignition switches," only so much protein transcription can occur.

What You Can Do About It

There are, however, theoretical and proven ways to increase the density of the receptors you have, or at least the sensitivity of those receptors.

Weight training itself increases both the number and sensitivity of androgen receptors, but I'll assume you're already doing the best you can through that route. 

Intermittent fasting works well, having been shown to almost double androgen sensitivity. But using this method in a bulking phase might be difficile, yet possible. Likewise, studies have shown that dietary whey (and possibly casein), along with supplements like zinc, carnitine tartrate and caffeine work well, too.

You could combine all of these dietary interventions together in the following way:

Take 25-50mg of zinc Upon waking, then about 30' later

have a cup or two of coffee with breakfast

Then, 1-2 more cups of coffee with 1-2 grams of carnitine tartrate 60-90' preworkout,on an empty stomach.

Have 1 to 2 daily servings of whey or a whey and casein protein blend as convenient.