Through the haze of misinformation clouding the supplement industry, strength athletes are often left wondering if anything will actually help them. Recently, a little known supplement has emerged that can do just that. In this article, we’ll take a look at this product and see how it can help with muscle growth, strength, and recovery.

Before we go any further, you need to know what we’re talking about. The supplement in question is called carnitine-l-tartrate (CLT), and there’s a good chance you’ll be using it for a long time to come. It’s different in both structure and mechanism of action from acetyl-l-carnitine, which is commonly sold as a fat loss supplement. So don’t worry if you’ve tried “carnitine” as an over-hyped “fat burner” and were disappointed by the results.

What does it do? CLT is a unique supplement because it increases the androgen receptor content of tissues. This means that there are more docking sites for our most plentiful anabolic hormone to function. In short, more testosterone/androgens reaching their target = a greater anabolic effect.

This sounds pretty amazing, right? Almost too good to be true, huh? I appreciate such skepticism, and in fact, quite encourage it. However, fortunately we have a growing body of evidence for this one. Better still, this evidence comes from one of the most prestigious exercise labs on the planet, with each study showing the efficacy of this supplement (Kraemer, et al. 2003; Kraemer, et al. 2006; Volek, et al. 2002).

Enter the Anabolic Index Score

So just how effective is CLT? Using the Anabolic Index Score, which objectively measures the anabolic potential of foods and supplements, CLT ranks as one of the most potent products available. When combined with protein pulse feeding, especially after a workout, the impact on muscle growth is great. This combined effect is so powerful because post-training meals also increase androgen receptor content. So you’re really maximizing the effect by combining the two (Kraemer, et al. 2006).

Quick Ttip: For those who are using HRT or other androgen related pharmaceuticals, CLT greatly increases the effectiveness of the cycle. In this situation, you would not only be gaining a pharmaceutically-induced elevation of androgen receptors but also a supplemental elevation.

Anabolism and recovery

We often get so wrapped up in our subculture that words adopt new meanings. Specifically in this case, I’m referring to anabolism (or “anabolic”), which is most commonly used in reference to muscle building, and ultimately, strength. Although this isn’t completely inaccurate for our purposes, it ignores a critical component of anabolism—muscle recovery.

By increasing muscle anabolism, regardless of the means, we’re definitively increasing the rate at which our muscle can recover from the training-induced stress we impose on it. Greater recovery means less down time and increased opportunity to incur the training stresses we seek (i.e. growth and strength). I’m sure you’re probably well aware of this fact, but it never hurts to have an occasional reminder.

To sum things up, by increasing the androgen receptor content of our muscle, CLT will be able to assist with the following critical variables:

  • Muscle strength
  • Muscle growth
  • Muscle recovery
  • Magnified effects of androgen use
  • Enhanced effects of post-workout meals

CLT is a legal supplement with potentially powerful effects on everything we want that is related to muscle. Better yet, it also has strong potential to improve neural strength and recovery—highly sought after processes that continue to elude us. Considering that we don’t fully understand neural adaptability, there’s much to be covered, which means that we’ll be discussing this in the next article.

Note: I have no stake, financial or otherwise, in any supplement.


Kraemer WJ, Volek JS, French DN, Rubin MR, Sharman MJ, Gómez AL, Ratamess NA, Newton RU, Jemiolo B, Craig BW, Häkkinen K (2003) The effects of L-carnitine L-tartrate supplementation on hormonal responses to resistance exercise and recovery. Journal of Strength and Conditioning Research 17(3):455–62.

Kraemer WJ, Spiering BA, Volek JS, Ratamess NA, Sharman MJ, Rubin MR, French DN, Silvestre R, Hatfield DL, Van Heest JL, Vingren JL, Judelson DA, Deschenes MR, Maresh CM (2006) Androgenic responses to resistance exercise: effects of feeding and L-carnitine. Medical Science and Sports Exercise 38(7):1288–96.

Volek JS, Kraemer WJ, Rubin MR, Gómez AL, Ratamess NA, Gaynor P (2002) L-Carnitine L-tartrate supplementation favorably affects markers of recovery from exercise stress. American Journal of Physiology: Endocrinology and Metabolism 282(2):E474–82.