L-Glutamine
Compiled from published pharmacological and botanical literature. Not independently verified by Herbuno. Spotted an error or have a correction? Flag it below →
| Compound | L-Glutamine |
|---|---|
| Chemical class | Conditionally essential α-amino acid — amide of glutamic acid |
| CAS | 56-85-9 |
| Primary source | Microbial fermentation, typically Corynebacterium glutamicum on a carbohydrate substrate |
| Key applications | Intestinal barrier support, nitrogen transport, substrate for rapidly dividing cells, post-exercise recovery |
| Claim strength | Moderate for gut barrier and catabolic states; Emerging for healthy-athlete recovery |
| Typical form | Free-flowing crystalline powder, 99%+ purity |
| Buy from Herbuno | L-Glutamine Powder 99% |
| Origin | Processed / Sourced from India |
| MOQ | R&D 100 g / 250 g (subject to stock) · Pilot batch 1–5 kg · Bulk 10 kg, 25 kg and above |
| Lead Time | Dispatch within 72 hrs from stock · fresh-batch production (typically 50 kg+): 10 working days |
| Documentation | CoA & MSDS standard with every lot |
Name origin: Glutamine takes its name from gluten, the wheat protein from which glutamic acid was first isolated by Karl Ritthausen in 1866. Glutamine is the amide form — glutamic acid with an added amino group on the side chain — which is precisely what makes it biologically interesting, since that second nitrogen is what the body moves around. The L- prefix denotes the physiologically active stereoisomer; the D- form has no nutritional role.
Discovery and production history: There is no ethnobotanical tradition here; glutamine is a cellular constituent, not a plant medicine. Its significance emerged through twentieth-century biochemistry, first as the most abundant free amino acid in human plasma and muscle, then through the recognition in the 1970s and 1980s that enterocytes and lymphocytes use it as a primary fuel rather than relying on glucose. That observation drove the entire clinical nutrition literature that followed. Industrial production moved from protein hydrolysis to microbial fermentation in the mid-twentieth century, the same technological shift that made monosodium glutamate a commodity.
Research trajectory: Glutamine was reclassified from non-essential to conditionally essential once it became clear that endogenous synthesis, while adequate in health, falls short during major trauma, burns, sepsis and prolonged catabolic stress. That framing drove enthusiastic adoption in critical care through the 1990s and 2000s. The correction came in 2013 with the REDOXS trial, which tested high-dose glutamine in critically ill patients with multi-organ failure and found higher mortality in the glutamine arm — a result that reversed guideline recommendations and remains the most important single finding in the literature.
Commercial source: Supplement and pharmaceutical glutamine is produced by fermentation using Corynebacterium glutamicum or related organisms on a glucose or sucrose substrate, followed by crystallisation and purification to 99% or above. The substrate is usually cane or corn derived, which is the point at which vegan, kosher, halal and non-GMO positioning is determined. The finished amino acid is identical regardless of substrate; what differs is the documentation trail, and that is what most buyers are actually purchasing when they specify origin.
Evidence for L-Glutamine Applications
The REDOXS finding has to lead any honest account. A large randomised trial of high-dose glutamine supplementation in critically ill patients with multi-organ failure reported increased mortality in the glutamine arm compared with placebo. This was not a null result but a harm signal, and it reversed the prior trend of guideline support for routine glutamine supplementation in critical illness. The dose was high and the population was severely ill with renal and hepatic compromise, so the finding does not transfer directly to a healthy adult taking a few grams daily. It does establish that glutamine is not inert and that "conditionally essential" does not mean "more is better under stress". Claim strength: High for the harm signal in that population.
The gut barrier rationale is mechanistically solid and clinically mixed. Enterocytes use glutamine as a preferred respiratory fuel, and glutamine depletion in cell and animal models produces villous atrophy and increased intestinal permeability. Human trials in conditions involving barrier compromise — short bowel syndrome, post-chemotherapy mucositis, some inflammatory bowel contexts — have shown benefit in some settings and not in others, with considerable heterogeneity in dose, duration and endpoint. The honest position is that the mechanism is well established while the clinical translation is inconsistent. Claim strength: Moderate.
In healthy, well-fed athletes the case is weak and should be stated as such. Glutamine is heavily marketed for muscle recovery, immune support during heavy training and reduction of exercise-induced gut permeability. Controlled trials in replete individuals have generally not shown meaningful effects on muscle protein synthesis, strength, body composition or illness incidence. The underlying reason is straightforward: a mixed diet containing adequate protein supplies several grams of glutamine daily, and endogenous synthesis from glutamate and ammonia is substantial. Supplementing a system that is not short does little. Claim strength: Emerging, trending negative.
Glutamine has a defined and approved role in sickle cell disease, which is worth distinguishing from the supplement positioning. Pharmaceutical-grade L-glutamine received US regulatory approval for reducing acute complications of sickle cell disease, on the rationale that it supports NAD redox balance in erythrocytes under oxidative stress. This is a specific indication at a specific dose in a specific population, and it is a pharmaceutical use. It should not be cited in support of general wellness claims, which is a misuse that appears regularly in category marketing. Claim strength: High within that indication.
Burns, major surgery and prolonged catabolic states remain the areas where supplementation has the most defensible rationale outside pharmaceuticals. In these settings plasma and muscle glutamine fall measurably, and the clinical question is whether restoring them improves outcomes. Enteral glutamine in burn patients has shown signals on infection rates and length of stay in some trials; parenteral high-dose use is where the harm signal arose. The distinction between enteral and parenteral route, and between moderate repletion and high-dose pharmacological intent, matters more in this literature than in most. Claim strength: Moderate.
Safety in healthy adults at normal supplemental doses is good, with the caveats above. Oral doses in the range of 5 to 30 grams daily have been used in trials without consistent adverse effects in people with normal renal and hepatic function. Glutamine metabolism generates ammonia, so hepatic impairment is a genuine contraindication rather than a precautionary one, and renal impairment warrants caution. There is no established tolerable upper intake level, which reflects absence of systematic assessment rather than demonstrated safety at any dose. Claim strength: Moderate.
Sourcing L-glutamine from Herbuno. We supply fermentation-derived L-glutamine powder at 99% purity, suitable for powder blends, sachets and capsule formats.
Specify your substrate requirement up front if you need vegan, non-GMO, kosher or halal documentation, since that is determined at the fermentation stage rather than downstream. All lots ship with CoA and MSDS as standard; request a quotation for pilot or bulk volumes.
Dosage & Formulator Specification
L-glutamine is dosed as the free amino acid at 99% or higher purity, so unlike mineral salts or vitamin triturations the declared weight is the delivered weight. Common supplemental doses run 5 grams daily for general gut-support positioning, with clinical protocols in catabolic states using 0.3 to 0.5 grams per kilogram of body weight daily, which for an 80 kg adult is 24 to 40 grams. That is a large powder volume and effectively rules out capsule delivery at clinical doses — a 5 gram dose alone is roughly ten size-00 capsules. Sachets, scoops and stick packs are the realistic formats above a few grams.
Solution stability is the defining formulation constraint and it is frequently underestimated. L-glutamine in aqueous solution degrades to pyroglutamic acid and ammonia, with the rate rising sharply with temperature and with deviation from neutral pH. This makes ready-to-drink glutamine products genuinely difficult: a beverage formulated with free L-glutamine will lose assay over shelf life and generate ammonia, which affects both potency and sensory profile. Dipeptide forms such as alanyl-glutamine exist precisely to solve this and are standard in parenteral nutrition for the same reason. For dry formats the issue does not arise, which is why the category is dominated by powders.
In dry blends glutamine is well behaved. It is a free-flowing crystalline powder with low hygroscopicity relative to several other amino acids, blends uniformly, and has a mild, faintly sweet taste that masks easily. It is compatible with most common excipients. The practical cautions are moisture control during storage, since absorbed water accelerates the same degradation pathway seen in solution, and avoiding high-temperature processing steps. Where glutamine is combined with electrolytes or acidic flavour systems in a powder intended for reconstitution, the stability clock starts when the consumer adds water, not before — which is acceptable but should be reflected in usage directions.
For analytical control, specify identity and assay by HPLC or ion-exchange chromatography with the result expressed as L-glutamine on a dried basis, and require optical rotation to confirm the L-configuration, since D- and DL- material has no nutritional value and is cheaper. Require pyroglutamic acid as a specified impurity, because it is the degradation marker that tells you how the material has been stored and handled before it reached you. Standard amino acid specifications should also cover residual solvents, heavy metals, microbial limits and loss on drying. For fermentation-derived material, the certificate should identify the production organism and the substrate.
Frequently Asked Questions — L-Glutamine
Is glutamine safe? I have seen it linked to increased mortality.
That refers to REDOXS, which tested high-dose glutamine in critically ill patients with multi-organ failure and found higher mortality in the glutamine arm. It reversed guideline support for routine use in intensive care. It does not transfer to a healthy adult taking five grams daily — different dose, route and population. But it does show glutamine is not inert, and hepatic impairment is a real contraindication because metabolism generates ammonia.
Does glutamine help muscle recovery in healthy athletes?
The controlled evidence does not support it. Trials in well-fed athletes have generally not shown meaningful effects on muscle protein synthesis, strength, body composition or illness incidence. A mixed diet with adequate protein already supplies several grams daily and endogenous synthesis is substantial, so there is little deficit to correct. We would not position a product on this claim.
Can I put L-glutamine in a ready-to-drink beverage?
Not easily. Free L-glutamine degrades in aqueous solution to pyroglutamic acid and ammonia, faster at elevated temperature and away from neutral pH. You will lose assay across shelf life and pick up off-notes. This is why the category is dominated by powders, and why parenteral nutrition uses dipeptide forms such as alanyl-glutamine instead.
What dose should a gut-support product carry?
Five grams daily is the common positioning dose. Clinical protocols in catabolic states run 0.3 to 0.5 g/kg/day, which is 24 to 40 grams for an 80 kg adult — that is a sachet or scoop format, not capsules. A five gram dose is already around ten size-00 capsules, so format should be decided before dose.
What impurity should I specify on the certificate?
Pyroglutamic acid. It is the degradation product of glutamine and therefore tells you how the material has been stored and handled before it reached you, which a simple assay figure will not. Also require optical rotation to confirm L-configuration, since D- and DL- material is cheaper and nutritionally useless.
Why source L-glutamine from India?
Roughly 80% of raw nutraceutical ingredients originate in China, and amino acids are among the most concentrated categories of all. A qualified second origin is a continuity measure rather than a cost play. India has established fermentation capacity and the documentation infrastructure for vegan, non-GMO, kosher and halal certification that this category typically requires.