Nutrition and Diet

What is Leucine, For What is it Used and its Side Effects

There are 9 essential amino acids and 3 branched chain amino acids (BCAA) required for healthy growth of muscles.

Leucine is one of the three BCAAs, the other two being isoleucine and valine. It is found that out of these three branched chain amino acids, leucine has the highest ability to stimulate muscle growth, can modulate insulin sensitivity, and it don’t get converted into fat. Let us understand first- what is leucine.

What is Leucine

As we have seen, leucine is one of the components of branched chain amino acids. Leucine can be taken along with other BCAAs (isoleucine and valine) and independently, however it is available separately because our body can absorb leucine faster as is synthesized easily.

Naturally, leucine is found in food sources like parmesan cheese, roasted soybeans, beef, chicken breast, pork, pumpkin seeds, tuna fish, octopus, peanuts, beans, etc.

Related Article: What is BCAA? And Why should you use it

Another notable property of leucine is that, it cannot be converted into sugar. Hence the chances of gaining extra fat by consuming leucine supplements becomes null. Leucine has following advantages-

  • It encourages muscle growth
  • It regulates the effect of insulin while digestion
  • It has catabolic effect on fat

Now, you might be wondering that when we get leucine inherently with BCAAs, then why to take it separately? Are the other BCAA components not effective and specifically what is leucine used for?

Well, let us discuss what is leucine used for.

What is Leucine Used for


Before we start, let us briefly go through the muscle mechanism to clearly understand its importance in our body.

When we exercise or lift weight, the muscle break down activity takes place. Then protein synthesis comes into play, which helps in repairing the broken tissues and accumulating more tissues to cope up with next slot of training. This makes the muscle look larger. Now what keeps up assisting in repairing the broken tissue is leucine.

Leucine helps to rebuild the tissues at a rate faster than any other supplement. This means, the muscles can be rebuilt and they need not compensate for muscle damage at the beginning of the process; hence all of the growth could contribute to the increased muscular volume.


Leucine is also used to reduce the fat accumulation (fats gets collected at unwanted places in our body due to irregular training routine or misses due to some other reasons) as they do not get converted into sugar by the liver, and as we all know, sugar is one of the major reasons for fat in our body.

Like the two sides of coin, there are some leucine side effects, with improper usage and irregular training routine. Let us discuss the leucine side effects in the trailing section.

Similar Article: BCAA vs Amino Acids: What is the Difference?

Side Effects of Leucine

Leucine can lead to hypoglycemia, a condition of low blood sugar level, as your leucine dietary intake do not get converted into sugar. To avoid this situation, one should not only depend on supplementation, regular food diet should be followed well.

Overdose of leucine can lead to increased blood ammonia levels, resulting in liver damage. The maximum recommended dose of leucine supplement is 500 mg per day, which can be taken in parts during the entire day.

There is also chances of decreasing serotonin production in the body. Serotonin is present in blood cells that contracts the blood vessels and help in transmitting signals to the brain. The reason is that as leucine is fast absorbing supplement, it competes with the absorption of other elements that are precursors of serotonin.

However research is going on to formulate leucine supplement such that its side effect is minimised, and to popularize it among the bodybuilders as it is highly effective for the muscle growth. And if taken in proper amount and regular exercise is incorporated, the best benefits from leucine can be achieved.

Friends, we understand your dilemma about integrating leucine supplement in your diet as leucine is comparatively new in the market than many other supplements and many of your fellow trainers might have yet not used it.

If you have any doubts about using leucine, feel free to contact us; we would be happy to help you out. Also, if you have already used leucine and want to share your experience with it, do not forget to drop in your comment.

Happy training!

Arushi Dutta

The author Arushi Dutta

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