Sports Research L-Glutamine - Workout Recovery, Immune Health & Gut Health Support - 5 G Per Serving - 17.64 Oz

Clinical trials typically use 5–10g per day in most clinical studies for gut and immune support; 10–20g used in some intensive recovery protocols. Sports Research L-Glutamine Powder delivers 5g L-Glutamine per scoop (1-2 scoops daily recommended), which we classify as Adequate relative to that range.

See the "Also consider" section below for two alternatives. Choose based on form preference (Powder vs alternatives), dose adequacy, and third-party testing.

Yes — Informed Sport Certified. Third-party testing verifies ingredient identity and label accuracy.

Yes — Amazon Subscribe & Save is available for this product. Enrolling locks in a recurring delivery at a reduced per-unit price.

L-Glutamine is generally considered safe and does not have well-documented interactions with most medications. However, individuals taking anti-seizure drugs (such as valproate or phenobarbital) should consult a physician, as glutamine can theoretically affect glutamate-GABA balance. Those on chemotherapy regimens should also seek medical guidance before supplementing, as glutamine’s effects in oncology contexts are actively studied.

Clinical studies using 5–10g of L-glutamine daily for up to 12 weeks report no significant adverse effects in healthy adults. Some individuals experience mild gastrointestinal discomfort — bloating or loose stools — particularly when starting at higher doses. Long-term data beyond 6 months is limited, but glutamine’s status as the most abundant amino acid in the body suggests favorable safety at moderate daily doses.

Glutamine powder is well tolerated by most users, and gut health support is actually one of its primary clinical applications. Rare users report mild bloating in the first week, especially at 10g doses, which typically resolves with continued use. The fermented source used in this product is particularly clean and unlikely to introduce contaminants that could irritate the gut.

Yes — L-glutamine stacks well with creatine, BCAAs, whey protein, and multivitamins without known interactions. It can be mixed directly into protein shakes or pre/post-workout beverages. Avoid combining with high-dose single amino acid stacks without dietary guidance, as amino acid competition for intestinal transporters is possible at very high total protein loads.

Mix 1 scoop (5g) into 8–10 oz of water, juice, or a protein shake once or twice daily. Most athletes take it immediately post-workout and again before bed for recovery and gut support. Stay well hydrated when using amino acid powders. Do not exceed 20g per day without medical supervision. Store in a cool, dry place and seal tightly after each use.

Gut permeability and mucosal benefits from L-glutamine typically appear within 2–4 weeks of consistent daily dosing in clinical research. Subjective workout recovery improvements — such as reduced muscle soreness — may be noticed within 1–2 weeks by athletes training 4+ days per week. Immune support benefits are cumulative and generally apparent after 4–6 weeks of regular use.