NutraBio L-Glutamine — 5g Fermented, Plant-Derived, 100 Servings

NutraBio L-Glutamine

5 grams of free-form L-glutamine per scoop, naturally fermented from plant material, with no additives, fillers or excipients. 100 servings.

The sourcing point is real, and worth knowing

NutraBio make a specific claim here that deserves explaining rather than repeating.

Amino acids can be produced by hydrolysing keratin — and keratin comes from animal hair, feathers and hooves. This is well documented in the food industry, most famously with L-cysteine used as a dough conditioner, some of which is derived from human hair sourced from barbershops.

NutraBio state their glutamine is vegetable-based and produced by natural fermentation, not synthesised or hydrolysed from keratin.

To be straight with you: a keratin-derived amino acid is not unsafe, and the finished molecule is chemically identical either way. But most people would rather know, and if you are vegetarian or vegan it matters a great deal. Fermentation is also the cleaner process.

⚠ An honest correction to a claim you will see everywhere

Marketing copy for glutamine — including some of NutraBio's own — cites a study where 2g of glutamine raised growth hormone by up to 400%.

That study is real. The conclusion drawn from it is not.

Growth hormone rises transiently from all sorts of things — sleep, hard training, fasting, several amino acids. A short-lived GH spike does not translate into muscle growth. The research that actually matters looks at whether glutamine supplementation increases muscle mass or strength in healthy, well-fed people, and it consistently finds that it does not.

We would rather lose the sale than repeat that one at you.

So what is glutamine genuinely good for?

There is a real case here, it is just not the muscle-building one.

Glutamine is the most abundant amino acid in your body, and under normal circumstances you make plenty of it. It becomes what researchers call conditionally essential — meaning demand can outstrip supply — under significant physiological stress.

The evidence-supported uses:

• Gut lining support. This is the strongest one. Enterocytes — the cells lining your small intestine — use glutamine as their primary fuel. It is not a systemic muscle supplement so much as a local fuel source for gut tissue. This is why it appears in our Intra Blast at 5g
• Immune function under heavy training loads. Immune cells also use glutamine heavily, and plasma glutamine drops after prolonged intense exercise. Some research links supplementation to fewer upper respiratory infections in endurance athletes during hard blocks
• Recovery when training volume is extreme — two-a-days, camps, or training through a deficit, where demand genuinely exceeds supply
• Anyone eating substantially below their needs, where dietary glutamine is low

If you train a few times a week and eat enough protein, you are unlikely to notice anything from this. Any protein-containing food supplies glutamine, and a 25g whey serving contains several grams.

Specs

L-Glutamine	5g per level scoop, free form
Source	Plant-based, naturally fermented
Other ingredients	None
Servings	100
Flavour	Unflavoured
Manufacture	NutraBio's own facility, USA

Free-form means it is a single unbound amino acid, absorbed without needing to be digested out of a protein first. That is what makes it useful as a targeted dose rather than simply eating more protein.

How to take it

• One level scoop (5g), two to three times daily per NutraBio's directions.
• On training days: 20 minutes before, immediately after, and optionally before bed.
• Mixes into anything. Unflavoured and it dissolves readily.
• Do not add it to very hot liquid. Glutamine is unstable at high temperatures — stir it into coffee once it has cooled, not boiling water.
• For gut support specifically, take it away from meals rather than with them.

Who this is for

• Anyone focused on gut health — the best-supported use
• Endurance athletes and anyone in a heavy training block or camp
• People training in a substantial caloric deficit
• Anyone doing two sessions a day
• Vegetarians and vegans who want a fermented, plant-derived source
• People who want the raw ingredient rather than paying for it inside a blend

Who this is not for

If you are buying it to build muscle, the evidence does not support that in healthy, well-fed people. Creatine does, and costs about the same.

If you eat plenty of protein and train moderately, you are already well supplied. Every protein food contains glutamine.

If you want it alongside a full amino profile, Intra Blast includes 5g with 10g of EAAs.

Speak to your doctor first if you have liver or kidney disease, where glutamine metabolism is affected.

Not for anyone under 18, pregnant or nursing.

Stack it with: creatine and beta-alanine if performance is the goal — those two carry the evidence glutamine does not.

Frequently asked questions

Does glutamine build muscle?
Not in healthy, well-fed people. The research consistently finds no meaningful effect on muscle mass or strength. Its real value is gut and immune support under heavy training loads.

What about the 400% growth hormone claim?
The study is real but the conclusion is not useful. Growth hormone spikes transiently from many things, including sleep and training, and a short-lived spike does not translate into muscle growth.

What is glutamine actually good for?
Gut lining support is the strongest case — the cells lining your small intestine use it as their primary fuel. Immune support during heavy training blocks is the second.

Where does it come from?
Plant material, by natural fermentation. Some amino acids on the market are hydrolysed from keratin, which comes from hair and feathers. NutraBio's is not.

How much should I take?
5g, two to three times daily.

Can I put it in coffee?
Let it cool first. Glutamine is unstable at high temperatures.

Do I need it if I drink protein shakes?
Probably not. A 25g whey serving already contains several grams of glutamine.

When should I take it for gut health?
Away from meals rather than with them.