L-Isoleucine for Faster Post-Exercise Recovery
L-isoleucine is an important branched-chain amino acid that’s known for its ability to support faster post-exercise recovery rates and muscle growth. It also provides energy and increases endurance.
Needless to say, the role l-isoleucine plays in muscle growth and recovery makes it a valuable inclusion in many bodybuilding supplements. In a similar vein, its prowess as an energy and endurance booster makes it a good addition to pre-workout formulations.
Although l-isoleucine is an incredibly popular supplement ingredient, many of the people who are enjoying its benefits or toying with the idea of taking advantage of them know very little about what l-isoleucine is or how it works.
This article is for the ones who want to know the facts about l-isoleucine and how it can help them move towards their goals.
L-Isoleucine v D-Isoleucine
Before going any further, it’s important to clear up any confusion there may be over l-isoleucine and d-isoleucine.
When people realize there is more than one form of leucine it often leads to a lot of head scratching. This is not made any better by the fact that it can be quite hard to find information about d-isoleucine and how it differs from l-isoleucine. Let’s set that right.
L-isoleucine and d-isoleucine are enantiomers. If that’s set you scratching your head as well, don’t worry. All it means is that if you were to examine both compounds on a molecular level you would discover they are mirror images of each other.
The Importance of L-Isoleucine in Comparison with Other Amino Acids
As you are probably aware, amino acids are obtained when protein is broken down into smaller particles the body can absorb and use. The body then uses them to build the protein we call “muscles”.
However, all amino acids belong to one of two groups:
- Non-Essential Amino Acids: You can get these from food. Especially high protein foods like meat, fish, and soy. Your body can manufacture them as well. So, if your diet lacks any of the non-essential amino acids it will make what it needs.
- Essential Amino Acids: You have to get essential amino acids from food because your body is incapable of manufacturing them. That means if your diet does not provide enough of them your training and growth will suffer.
Muscle tissue consists of 20 amino acids. The body can manufacture 11 of them. It has to get the rest of them from food.
So, when you are trying to create a healthy diet plan your essential amino acid requirements will need special consideration. L-isoleucine is an essential amino acid. [SOURCE]
However, together with the essential amino acids l-leucine and valine, l-isoleucine belongs to a special category of amino acids. All three are branched-chain amino acids (BCAAs).
On a molecular level, BCAAs are different from other amino acids because they have three branched chains. That’s strictly science book stuff though. It’s unlikely to interest the average supplement user.
When it comes to the muscles, BCAAs have extra importance. They account for around 30 percent of all muscle tissue. That’s why so many people take l-isoleucine and the other BCAAs in supplement form.
As far as the pecking order goes, l-leucine is the most important BCAA. L-isoleucine takes second place and valine comes in third.
How L-Isoleucine Affects Blood Glucose
L-isoleucine may not be the most important of the three BCAAs but it outperforms both in one area. When it comes to improving glucose uptake, the other two can’t touch it. [SOURCE]
This makes it an ideal amino acid for people with hypoglycemia (low blood sugar). Its ability to improve glucose uptake is also the reason why l-isoleucine is good for providing extra energy and endurance.
It’s also important to note, the amino acid’s ability to increase muscle glucose uptake is significant. In one study, oral administration of l-isoleucine resulted in a 71 percent improvement in muscle glucose. [SOURCE]
L-Isoleucine and Hemoglobin
L-isoleucine also plays an important role in hemoglobin production. Hemoglobin is found in the red blood cells. It has the task of retaining the oxygen picked up by the cells on their journey through the lungs. [SOURCE 1, SOURCE 2]
Most people are aware the red blood cells carry oxygen around the body. Less realize the role hemoglobin plays. If you liken the cells to a bus and oxygen to its passengers, hemoglobin is the conductor that lets the passengers in and drops them off at all the stops along the way.
The relationship between l-isoleucine and hemoglobin should not be taken lightly. It has an important bearing on the amino acid’s ability to improve endurance.
Energy production within the muscle works best in an oxygen-rich atmosphere. It’s not all about glucose. You can have all the glucose you want in the muscles, it won’t help you if oxygen levels run too low.
When runners become out-of-breath they have to stop. That’s because their lungs cannot keep up with oxygen requirements the muscles are imposing.
Getting out of puff is not the only sign the muscles are short of oxygen. Intense exercise with insufficient oxygen also causes lactic acid to build up.
Lactic acid is what causes the muscle burn that ultimately forces you to stop when you are working your muscles too hard. [SOURCE]
Because it supports hemoglobin production, l-isoleucine assists the supply of oxygen to the muscles. In so doing, it also does its bit to help you work your muscles harder before fatigue sets in.
The Benefits in Real Terms
So, l-isoleucine builds muscle and helps ensure the muscles have plenty of glucose and oxygen. That’s great. But what does it mean in real terms?
Well, for one thing, it will help you to train with more intensity and do so for longer before fatigue sets in.
There’s a saying about people only getting out what they put in. By allowing you to put more into your chosen exercise/sporting activity l-isoleucine will help you get more in return.
In reality that’s likely to be things like faster track speeds (athletes) and improved muscle growth (bodybuilders).
Because it promotes improved protein synthesis, this important BCAA will also help you to heal faster. That will mean faster recovery and less muscle soreness.
Due to the fact that it assists hemoglobin production, supplements that provide l-isoleucine can also support cognitive function. The muscles are not the only things that require oxygen. Lots of other organs do too, including the brain. [SOURCE]
Additionally, by assisting the oxygen supply to the brain, l-isoleucine also supports improved mental focus and clarity. Lots of people are held back in their physical pursuits by a lack of focus, so this is also an important consideration.
Foods that Provide L-Isoleucine
The best natural sources are generally high-protein food such as milk, fish, and dairy products. However, there are some surprisingly good plant-based options suitable for vegetarians an and vegans.
Some good food choices include:
- Sirloin steak
- Chicken breast
- Turkey steak
- Lamb chops
- Sunflower seeds
L-isoleucine is a versatile amino acid that’s needed for muscle repair and growth. Together with l-leucine and valine, it accounts for around of third of all human muscle mass.
It’s also good for boosting energy and endurance, so it has a lot to offer athletes of all types.
It provides post-workout, mid-workout, and post-workout benefits by boosting performance and promoting fast healing. So it’s not surprising l-isoleucine is such a common supplement ingredient.
However, the best way to take advantage of l-isoleucine may be to take it as part of a BCAA supplement or one that provides a full amino acid profile. Especially if you are focusing on gains in muscle and strength.
Using it in this way will help ensure the muscles have everything they need. L-isoleucine is undoubtedly an important muscle-building ingredient but it’s only one of 20 that are needed for the full recipe.