L-glutamine, sometimes simply called glutamine, is an amino acid that plays a key role in many aspects of your health.
In fact, studies show that it’s essential for immune health, cell function, and metabolism (1).
What’s more, some proponents assert that glutamine supplements promote weight loss and fat burning. Yet, you may wonder whether these claims are true.
This article explains whether L-glutamine helps you lose weight.
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Although research is limited, several studies link glutamine supplements to increased weight loss.
For instance, a 6-week study in 66 people with type 2 diabetes found that taking 30 grams of glutamine powder daily improved multiple risk factors for heart disease and reduced both belly and body fat (2).
Similarly, a 2-week study using the same amount of glutamine observed decreased waist circumference, a marker for belly fat, in 39 people with overweight or obesity (3).
In another small study, 6 women who took glutamine supplements for 4 weeks experienced significant reductions in body weight and belly fat without making other dietary or lifestyle changes (4).
Yet, a study in 24 adults indicated that taking 6 grams of glutamine led to an increase in meal size, which may hinder weight loss (5).
Moreover, another study that examined the effects of taking a glutamine supplement in combination with exercise noted no benefits for body composition or muscle performance (6).
Keep in mind that all of these studies used very small sample sizes and only evaluated the short-term effects of glutamine supplements.
Therefore, more high quality research is needed.
summarySeveral small studies suggest that glutamine supplements may promote short-term weight loss, but further research is needed.
How does glutamine work?
Research suggests that L-glutamine supports weight loss through several mechanisms.
First, some studies indicate that L-glutamine supplements alter the composition of your gut microbiome, which is the community of beneficial bacteria in your digestive tract (7, 8).
The gut microbiome plays a central role in many aspects of health, including weight management (9, 10).
What’s more, glutamine may protect against inflammation, which is linked to many chronic conditions, including obesity (3, 11, 12).
Finally, while studies show that L-glutamine may improve blood sugar control, there’s conflicting evidence on whether it affects insulin — the hormone responsible for transporting sugar from your bloodstream into your cells (13).
However, some human and animal studies suggest that glutamine enhances insulin sensitivity, improving your body’s ability to use insulin efficiently. This may aid weight loss, as impaired insulin sensitivity is likely tied to a higher risk of weight gain and obesity (3, 14, 15, 16).
Still, more research is needed to evaluate the relationship between glutamine and insulin sensitivity.
summaryL-glutamine may promote weight loss by altering the composition of the gut microbiome, decreasing inflammation, and improving insulin sensitivity. Nonetheless, further studies are necessary.
How to use it
Glutamine is found naturally in a variety of foods, including tofu, eggs, milk, and beef (17).
It’s also available in supplement form, including powders and capsules, which are widely considered safe when used as directed (18).
Most doses range from 500 mg to 3 grams and should be taken daily between meals. In a limited number of studies, doses of up to 30 grams per day have been shown to be effective for weight loss (2, 3).
However, while short-term use is likely safe, more research is needed to evaluate the potential side effects of supplementing long term (19).
Start with a lower dose and increase slowly to assess your tolerance.
Additionally, be sure to talk to your healthcare provider before adding any new supplements to your routine.
summaryGlutamine is found in both foods and supplements. It’s generally considered safe for short-term use, and a limited number of small studies in specific populations have shown that doses of around 30 grams per day may aid weight loss.
The bottom line
L-glutamine is an amino acid found in many foods and supplements.
Although research is limited, some studies suggest that it boosts short-term weight loss by altering the composition of your gut microbiome, reducing inflammation, and improving insulin sensitivity.
Nonetheless, its long-term effects aren’t known. More research is needed.
Additionally, glutamine shouldn’t be considered a quick fix for weight loss. Instead, you should pair it with a balanced diet and healthy lifestyle for the best results.