Best L-Glutamine Supplements 2026: Cost per Effective Dose
Top pick for L-Glutamine: Naked Nutrition Pure L-Glutamine Powder (1 kg, 200 servings) — 5,000mg L-glutamine per 1 scoop (5 g), None (3rd-party heavy-metal tested), $0.17/day. Our pick.
Registry check · L-Glutamine
Does anyone independently verify L-Glutamine supplements?
5 of the 12 L-Glutamine products on this page are confirmed in Informed Sport / Informed Choice and NSF/ANSI 173: BulkSupplements L-Glutamine Powder (1 kg); BulkSupplements L-Glutamine Powder (500 g); NOW Sports L-Glutamine 1000 mg (120 Veg Capsules); Sports Research L-Glutamine Powder (500 g); Thorne L-Glutamine Powder (513 g, 90 servings). NOW Sports L-Glutamine 1000 mg (120 Veg Capsules); BulkSupplements L-Glutamine Powder (1 kg); Sports Research L-Glutamine Powder (500 g); BulkSupplements L-Glutamine Powder (500 g) do not show the mark on the listing, so the table’s certification column, which repeats the listing, does not show it either. For the others, the listing may name a certification, but we did not find it in a public registry — that is not evidence against them, only an absence of independent confirmation.
Certification is not a dosing guarantee. Across the whole catalogue, certified products reach the clinically studied dose 57% of the time and uncertified ones 71% — a gap too small to mean anything (Fisher p = 0.185). Read the L-Glutamine dose column either way.
The 12 products on this page checked against all 5,317 US NSF, USP and Informed Sport listings, 2026-08-25. Full method and limitations.
What L-Glutamine labels show
Priced per day, these L-glutamine products run $0.07 to $0.74 — a 11× gap between the cheapest and dearest L-glutamine here, across 9 brands.
Which row that favours is not obvious: Horbaach Horbaach L-Glutamine 1000 mg (180 Capsules) is cheapest per serving at $0.07, but its serving sits below the median here, so part of that price gap is simply a smaller capsule.
All L-Glutamine Supplements Compared
| Product | Brand | Dose / Serving | Cost / Day | Certification (as labelled) | Pick | Buy |
|---|---|---|---|---|---|---|
| Horbaach L-Glutamine 1000 mg (180 Capsules) | Horbaach | 1,000mg L-glutamine / 1 capsule (1 g) | $0.07 | None | Buy | |
| Optimum Nutrition L-Glutamine 1000 mg (240 Capsules) | Optimum Nutrition | 1,000mg L-glutamine / 1 capsule (1 g) | $0.08 | None | Buy | |
| NOW Sports L-Glutamine 1000 mg (120 Veg Capsules) | NOW Foods | 1,000mg L-glutamine / 1 capsule (1 g) | $0.13 | None (cGMP) | Buy | |
| Naked Nutrition Pure L-Glutamine Powder (1 kg, 200 servings) | Naked Nutrition | 5,000mg L-glutamine / 1 scoop (5 g) | $0.17 | None (3rd-party heavy-metal tested) | Our Pick | Buy |
| BulkSupplements L-Glutamine Powder (1 kg) | BulkSupplements | 5,000mg L-glutamine / 1 scoop (5 g) | $0.18 | None (3rd-party tested) | Buy | |
| Nutricost L-Glutamine Powder (500 g) | Nutricost | 5,000mg L-glutamine / 1 scoop (5 g) | $0.23 | None (3rd-party tested) | Buy | |
| Sports Research L-Glutamine Powder (500 g) | Sports Research | 5,000mg L-glutamine / 1 scoop (5 g) | $0.25 | None found in a public registry | Buy | |
| BulkSupplements L-Glutamine Powder (500 g) | BulkSupplements | 5,000mg L-glutamine / 1 scoop (5 g) | $0.25 | None (3rd-party tested) | Buy | |
| NOW Sports L-Glutamine Pure Powder (1 lb) | NOW Foods | 5,000mg L-glutamine / 1 rounded tsp (5 g) | $0.25 | None (cGMP) | Buy | |
| Optimum Nutrition L-Glutamine Powder (1000 g) | Optimum Nutrition | 5,000mg L-glutamine / 1 scoop (5 g) | $0.29 | None found in a public registry | Buy | |
| Life Extension L-Glutamine Powder (100 g) | Life Extension | 2,000mg L-glutamine / 1/2 tsp (2 g) | $0.33 | None | Buy | |
| Thorne L-Glutamine Powder (513 g, 90 servings) | Thorne | 5,000mg L-glutamine / 1 scoop (5 g) | $0.74 | NSF Certified for Sport | Buy |
Our Picks
Our Pick: Naked Nutrition Pure L-Glutamine Powder (1 kg, 200 servings)
5,000mg L-glutamine per 1 scoop (5 g). None (3rd-party heavy-metal tested). $0.17/day. 200 servings per container at $34.99.
Naked Nutrition Pure L-Glutamine Powder (1 kg, 200 servings) →
The shelf · L-Glutamine
These L-Glutamine servings are not comparable to each other
Horbaach L-Glutamine 1000 mg (180 Capsules) states 1,000 mg a serving and Thorne L-Glutamine Powder (513 g, 90 servings) states 5,000 mg, both occupy one row of the same price column. So Horbaach L-Glutamine 1000 mg (180 Capsules) showing $0.07 a day, the lowest here, may be reporting a smaller serving rather than a better price. Before comparing Horbaach L-Glutamine 1000 mg (180 Capsules) with Thorne L-Glutamine Powder (513 g, 90 servings), check what each calls a serving.
Method: the 12 L-Glutamine products above, compared on label facts, serving size, servings per container, form, price. Not a dosing recommendation.
How these 12 L-Glutamine products were ranked
5 of these 12 are confirmed in a certifier's registry — the only L-glutamine rows where the claim is independently backed — and the rest are ranked on cost per day at the labelled serving. Commission does not enter it: the rate is the same whichever L-glutamine you buy. Full methodology.