Clean Glutamine

Glutamine is the supplement where the biochemistry is far more impressive than the trials in healthy people, so our naturopaths spend most of this conversation separating the two.

A good fit if

• Gut lining is the reason, and you'll take a powder at a dose you can actually reach
• You can give it eight weeks, which is how long the one strong gut trial ran
• You'd rather buy the plain powder than a peptide blend with an unsupported absorption story
• Your kidney function is normal and you take no prescription medicines
• You're comfortable with an honest maybe. Mechanism is good, pooled clinical evidence in mixed populations is null

Check with us first if

• You have any kidney concern. Glutamine can cause glomerulosclerosis and raised creatinine in the setting of diabetic nephropathy, which is the clearest safety signal outside hospital.
• You have liver disease or anything affecting how you handle ammonia. Glutamine is metabolised to glutamate and ammonia, both of which have neurological effects.
• You're planning to take it long term. The safety literature says explicitly that chronic consumption by healthy people of all ages has not been fully studied.
• You have type 2 diabetes. 30 g a day for six weeks did nothing to postprandial glucose or insulin, so it isn't a blood-sugar strategy either way.
• You're taking any prescription medicine. No specific interaction with oral glutamine is documented anywhere here, and absence of data is not absence of interaction.
• You're buying it for training. The dedicated meta-analysis of 47 studies is negative, and a protein powder is the better answer for recovery.
• If you take prescription medicines, check with your doctor, pharmacist or our naturopaths before starting.

• L-glutamine free-form powder. Best known for: The standard retail product: plain crystalline amino acid, near-tasteless, dissolved in water. Absorption: No head-to-head absorption study exists here; every trial in the gut evidence used oral glutamine. Typical use: The form used in the one strong gut trial at 5 g three times daily, and the only format you can realistically reach 15 g a day with.
• L-glutamine capsules and tablets. Best known for: The same substance in a smaller per-unit dose. Absorption: No separate evidence. It's the same molecule. Typical use: Convenience only. Reaching 15 g a day means 15 to 30 capsules depending on strength, which is the practical problem with the format.
• Alanyl-glutamine dipeptide. Best known for: Two amino acids bonded together, more stable in solution, which is why hospital intravenous products use it. Absorption: No oral absorption comparison against free glutamine exists here. Typical use: Permitted for oral medicines only in Australia. Every trial held here used it intravenously or in dialysis fluid, and those results don't transfer to a scoop of oral powder.
• Effervescent glutamine. Best known for: A dissolving-tablet format. Absorption: Not studied comparatively. Typical use: One small tolerability trial gave 12.4 g a day for 60 days to 30 older adults and found no change in any measured parameter and no adverse effects.
• Glutamine in arginine or HMB combination formulas. Best known for: Sold as recovery or wound-repair blends. Absorption: Not applicable. Typical use: Confounded. A 15-study review states glutamine was examined only in combination with arginine, which limits any insight into its isolated effect. Never attribute a blend's result to the glutamine in it.
• Glutamine peptides (protein hydrolysate powders). Best known for: Marketed as better absorbed than free glutamine. Absorption: No evidence held here supports that. Typical use: A hydrolysate is a different ingredient from the permitted glutamine item, and the better-absorbed claim has no source behind it.
• Glutamic acid and glutamate. Best known for: Different substances that get confused with glutamine because of the names. Absorption: Not applicable. Typical use: Glutamic acid is permitted only for topical medicines for dermal application in Australia. It is not an oral glutamine substitute, and monosodium glutamate is a different substance again.

Reference values. There isn't one. Glutamine has no Australian reference value. It isn't among the nutrients the NHMRC covers, so there's no recommended intake and no percentage-of-daily-need figure available. Anything phrased that way has been invented.

Typical supplemental range. Australian powders are commonly scooped at around 5 g, taken one to three times a day. The trial doses worth knowing: 15 g a day as 5 g three times, for eight weeks, in the post-infectious IBS trial. Which is the one dose that both matches what's sold here and has a strong result behind it. Elsewhere, 12.4 g a day for 60 days in older adults and 30 g a day for six weeks in type 2 diabetes, the latter with no effect on glucose or insulin at all. In athletes, short-term doses of 20 to 30 g within a few hours and 0.1 g per kilo four times daily for two weeks were associated with no significant adverse effects.

Upper level. No regulatory cap exists, so every limit here is an evidence judgement rather than a legal one. The general tolerance position is that up to 30 g a day can be given without important side effects. Above 200 mg per kilo of body weight, an athlete meta-analysis picked up a reduction in neutrophils. Not a benefit, and worth knowing if you're dosing by scoop count rather than by weight.

Worth knowing. On timing, there's less to say than the marketing implies: the only protocols held here are three divided doses daily, and one trial that gave it in half a glass of ice-cold water 5 to 10 minutes before each main meal. Nothing supports an empty-stomach rule or a post-workout window, so don't let a label convince you otherwise. Your needs depend on your age, diet and health circumstances. Talk to one of our naturopaths.

This list is the part of the page we will not shorten. If any of it applies to you, talk to one of our naturopaths or your doctor before starting.

• Critically ill adults with multi-organ failure. Early combined intravenous and enteral glutamine was associated with higher 28-day, in-hospital and 6-month mortality.
• Diabetic nephropathy or impaired kidney function. Glutamine can cause glomerulosclerosis and raised serum creatinine in that setting.
• Liver disease, or any condition affecting ammonia handling. Glutamine is metabolised to glutamate and ammonia, both with neurological effects.
• Anyone planning chronic use. The safety literature states chronic consumption by healthy people of all ages has not been fully studied.
• Pregnancy and breastfeeding. No evidence either way; route to a practitioner and do not reassure.
• Children. Tolerated in supervised clinical trials, but no retail dose for healthy children is established.
• Above 200 mg per kilo of body weight. An athlete meta-analysis found reduced neutrophils at that level.
• Anyone on prescription medicine. No interaction is documented, which is not the same as no interaction existing.
• The TGA advisory cache is empty, so this entry cannot state whether any safety advisory about glutamine exists.
• If you take prescription medicines, check with your doctor, pharmacist or our naturopaths before starting.