L-Glutamine is produced by the body and available in everyday foods, but is also a popular supplement due to its potential health and performance benefits. Glutamine exists in two different forms, L-glutamine and D-glutamine, which only vary in molecular structure. In this article we’ll be focusing on the specific health benefits and side effects of L-glutamine.
What is L-Glutamine?
L-Glutamine is an amino acid — a building block of protein. Amino acids and proteins are incredibly important in the body. In L-glutamine’s case, it plays a part in neural function, intestinal function and keeping our immune systems healthy.
It’s considered a ‘non-essential’ amino acid because it’s made by the body naturally in our muscle tissue. So we don’t necessarily need to consume it from our diet. But when we’re exercising, whether that be lifting weights or doing a HIIT session, our body will likely require more glutamine that it makes on its own as it’s under metabolic stress. This is why many argue that L-glutamine is ‘conditionally essential’, as there are times when additional glutamine is needed.
The fact that L-glutamine is made by our muscles, is common in our diet, and circulates in our blood, makes pinpointing its effects challenging, but it’s clear that it plays an important role in the body both during exercise and recovery from serious illness.
1. Quick Recovery
Research has shown that athletes can benefit from L-glutamine supplementation to decrease muscle soreness and improve recovery time.
This amino acid plays a crucial role in controlling glucose (energy) uptake by the muscles after exercise, which can help restore their energy stores for your next workout. When your muscles have optimal glucose stores, you perform better and take longer to fatigue.
Long periods of strenuous training have been shown to decrease blood glutamine levels, making L-glutamine potentially a very useful supplement for your post-workout nutrition plan.
2. Increased Lean Body Mass and Power
Studies have shown additional potential benefits, such as:
- Limited strength loss and reduced muscle soreness
- Feeling less fatigued
- Longer time until exhaustion in endurance exercise
3. Weight Loss
Coupled with increased body mass often comes weight loss — muscle tissue burns more than fat tissue, and increases your metabolism over time. Diets high in protein and amino acids like glutamine are more filling because they slow down digestion and signal to your brain that you are full – potentially reducing overall calorie intake.
Glutamine has also been shown to help with blood sugar regulation and prevention of obesity after consistent supplementation.
4. Boost in Immunity
Athletes who follow intense training schedules tend to have weakened immune systems due to the constant physical stress of high-intensity exercise.
L-glutamine is actually used to help the immune system of critically ill patients in hospital, due to its protective effect on cells in our immune system.
Research shows that L-glutamine plays a role in both immune cell production (having enough to fight off germs) and the gut’s function as a physical barrier to infection. For these reasons, there may be a potential benefit to your immune system from an L-glutamine supplement as well.
Intakes of 20-30g of glutamine or 0.65g/kg of body mass have been used in research studies and not shown any ill effects in short term use. However, you likely only need 3-5 grams daily to meet your body’s needs.
Because glutamine has shown to be in lower concentrations after intense training sessions, it’s essential to take it after your workout to help your muscles to rebuild and grow.
It can be taken on its own or as part of your post-workout protein shake since protein is another key for muscle recovery and building. L-glutamine’s role in controlling glucose (energy) usage during workouts means it can be useful to take it before a workout instead.
Potential Side Effects
Dizziness was listed of a side effect in a research participant taking 25 grams per day, and went away when the dosage was decreased.
There are limited potential side effects of taking L-glutamine, as it’s both made by the body and present in many foods. However, long term supplement use of glutamine may have impacts that we don’t fully understand. Amino acids like glutamine are transported through the body by specific systems, and often several amino acids compete for the same transporters. If there is a constant surplus of glutamine, it may be more difficult for the body to adequately use competing amino acids.
If you’re unsure about the potential side effects L-glutamine might have on you, always talk to your GP before taking them.
Take Home Message
L-glutamine is an important amino acid that plays many roles in our bodies regardless of our level of exercise. However, the stress that exercise puts on our body can deplete our L-glutamine levels, making it a useful supplement for athletes.
It shows many potential benefits to performance, recovery, and body mass, with limited side effects. It can also be useful to boost our immune system and help sustain adequate levels in those who follow low-protein diets.