Which L-glutamine brands are third-party tested?
6 of the 32 L-glutamine products we track are named at the exact package by a certifier. 2 more are listed by a program that names no package (Informed Sport). 18 appear in no database we searched. 6 match a listing that may cover them, and whether it does is not settled either way, so they are listed separately below rather than counted as absent.
NSF names packages by size and count against each certificate. A brand can sell the same formula in several sizes, or several flavors, and have one of them named, so “this brand is NSF certified” can be true while the tub in your hand is not one NSF names.
Each row's format, size and serving come from the brand's own label and store page.
Certifier names this exact package, 6
The strongest evidence available here. For NSF, the listing names the package size sold; it was opened, its package text recorded, and its ID is on the product page. For USP, which names products rather than packages, the product is in USP's directory and the USP Verified Mark is on this package's own label, and both are on the product page.
| Product | Type | Per 5 g | Certificate |
|---|---|---|---|
| BulkSupplements.com L-Glutamine Powder, Mango Tango (700 g) | Powder | $0.34 | 1825995 |
| BulkSupplements.com L-Glutamine Powder, Lemon Italian Ice (700 g) | Powder | $0.34 | 1825994 |
| BulkSupplements.com L-Glutamine Powder, Sour Apple (700 g) | Powder | $0.34 | 1825993 |
| BulkSupplements.com L-Glutamine Powder, Orange Smash (700 g) | Powder | $0.35 | 1825992 |
| Momentous L-Glutamine (300 g) | Powder | $0.667 | 1618476 |
| Thorne L-Glutamine Powder (90 servings) | Powder | $0.744 | 1509493 |
Certified, no package named, 2
Certified by a program that lists a product rather than a package: Informed Sport, Informed Choice and IFOS (International Fish Oil Standards) name no tub, bottle or count, so a listing covers the product, not a package size. The lot printed on a package can be checked against the lots the certifier lists. USP names no package either; a USP package counts as confirmed only when USP's directory lists the product and the package's own label carries the USP mark, which USP says is how a buyer can tell a product is verified. Informed Sport and IFOS test every batch; Informed Choice tests periodically, by each program's own description. That is real independent testing of the product; it is not a statement that the package in your hand was the one tested.
| Product | Type | Per 5 g | Certificate |
|---|---|---|---|
| Sports Research L-Glutamine, Unflavored (300 g) | Powder | $0.249 | Informed Sport |
| Sports Research L-Glutamine, Unflavored (500 g) | Powder | $0.279 | Informed Sport |
Searched, and not found, 18
Not listed by NSF Certified for Sport, Informed Sport, Informed Choice or USP Verified when we read each one's list. These programs certify what a company submits to them, so a product can be absent from a list simply because it was never entered, which is not a finding against it.
Not settled either way, 6
A certifier's list holds an entry that may cover these, and the entry does not say whether it does. Neither confirmed nor absent; each product page has the detail.
| Product | Type | Per 5 g | Certificate |
|---|---|---|---|
| BulkSupplements.com L-Glutamine Powder, Unflavored (1 kg) | Powder | $0.20 | Not settled |
| BulkSupplements.com L-Glutamine Powder, Unflavored (500 g) | Powder | $0.29 | Not settled |
| Optimum Nutrition Glutamine Powder, Unflavored (1 kg) | Powder | $0.332 | Not settled |
| BulkSupplements.com L-Glutamine Powder, Unflavored (250 g) | Powder | $0.479 | Not settled |
| Optimum Nutrition Glutamine Powder, Unflavored (300 g) | Powder | $0.491 | Not settled |
| BulkSupplements.com L-Glutamine Powder, Unflavored (100 g) | Powder | $1.05 | Not settled |
NSF Certified for Sport, the Informed programs' published product lists and USP's directory are each read in full, and each product page names the day. A product missing from this page has not failed a check. It has not had one.
Where to buy: the L-glutamine shortlist
The pick is the cheapest certified product, at the exact package sold where the certifier names packages, with no adverse finding on record, a price its retailer let us read recently, and no more than a year’s supply at the label’s serving; per delivered dose where the retailer publishes a delivery rate. Where none does, it is the cheapest such product before delivery, and it says how far the order is from free delivery. It is the same pick the category page shows. Any answer shown beside it is the cheapest under a different rule and says so on its own line; answers that cost more than the pick fold under one line until you ask for them.
How these lines are chosen
Among 27 products and 27 retailer listings we track; Amazon and Walmart are not included. A month is thirty doses of the size in the heading, priced the same way as the per-dose figure beside it. “Delivery known” ranks only products whose retailer publishes a delivery rate; a cheaper product with an unpublished rate is on its own line, or in the full list below.
How these lines are chosen
Among 5 products and 5 retailer listings we track; Amazon and Walmart are not included. A month is thirty doses of the size in the heading, priced the same way as the per-dose figure beside it. “Delivery known” ranks only products whose retailer publishes a delivery rate; a cheaper product with an unpublished rate is on its own line, or in the full list below.
A pick has to be independently certified, at the exact package sold where the certifier names packages, with no recall or failed test, a price its retailer let us read recently, and no more than a year’s supply at the label’s serving. Where the retailer publishes no delivery rate, the pick is priced before delivery and says so. Nothing we track here clears all of those yet. Each of these misses at least one bar, and says which:
Full comparison of every product in this category: L-Glutamine. Every question we answer: the question index.
What this rests on: prices we last recorded at the retailer named on each product page, which go stale, and each page says when it was checked; the products we track, not every product sold, and Amazon and Walmart are not among the stores; listings and labels read at the source, each linked from the page. Found an error? Tell us. The full method: How we compare.