Firstly Carnitine is mainly popular in the bodybuilding community for being a weight loss supplement. Supposedly carnitine works by using fat as energy allowing for greater fat loss. In my opinion, using carnitine as a fat burner is very questionable and there other smarter weight loss methods you can take that can utilize fat as energy such as intermittent fasting (How to increase testosterone levels while losing weight). Besides being used as weight loss supplement research shows it may give men some hormonal advantages as well.

Can carnitine boost the amount of “testosterone receptors”

Carnitine is a trimthylated amino acid found primarily in animal proteins, with red meat regarded as the richest source, although humans are also capable of synthesizing L-carnitine from dietary amino acids. The body does not produce high amounts of carnitine on its own, and (like testosterone) carnitine levels decline as we age, also contributing to the aging process. Research suggests carnitine can increase the quantity of active androgen receptors within the body.

What are Androgen receptors?

Androgen receptors are a type of nuclear receptor that is activated by binding either of the androgenic hormones, testosterone, or dihydrotestosterone in the cytoplasm and then translocating into the nucleus.

In theory this should lead to greater utilization of Free testosterone within the body.

 The University of Connecticut’s Human Performance Laboratory tested the effects of L-Carnitine on its ability to enhance free-testosterone utilization. In the 21-day human clinical study, L-Carnitine increased the number of androgen receptors compared to results produced by a placebo group.

Carnitine was proven to increase the number of active androgen receptors in the human body, meaning that it increases the amount of “testosterone receptors”, the receptor sites where androgens (testosterone and DHT) actually bind into (study).

Why is increasing androgen receptors such a big deal?

Increasing androgen receptors increases the utilization of free testosterone. Believe it or not only about 2 percent of testosterone in the normal male is free testosterone, so finding a way to enhance free testosterone utilization without affecting natural testosterone production is nothing short of a breakthrough. Free testosterone is more beneficial for muscle development the other  98 percent of testosterone (bound testosterone)  is not as useful for muscle gains.

Studies also suggest carnitine has been found to improve the quality of human sperm, this can be linked to an increase of testosterone utilization (studystudy,).

Which carnitine to use?

(L-carnitine-L-tartarate) are the forms used in the studies in regards to increasing androgen receptor density. Note: One other way to increase carnitine is to supplement with L-Lysine (study). It is suggested to consume between 650-4,000 mg’s of carnitine per day.

Read the Pure L-Carnitine L-Tartrate Powder reviews


Is supplementation with carnitine worth a try? I would say yes especially for older men this is due to there being a lack of supplements proven to increase androgen receptors Carnitine might be one solution. But I wouldn’t get too excited about it or expect too much. The main concern I have is the lack of studies done on carnitine and the one that always gets mentioned was only done with 10 participants.