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Types of L-Glutamine: Forms & Bioavailability

Evidence:Moderate
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This content is for informational purposes only and does not constitute medical advice. Statements about dietary supplements have not been evaluated by the FDA and are not intended to diagnose, treat, cure, or prevent any disease. Individual results may vary — consult your healthcare provider before starting any supplement. Full disclaimer

Forms Comparison

FormBioavailabilityBest For
L-Glutamine PowderHighCost-effective bulk form — dissolves in water; most popular for higher doses
L-Glutamine CapsulesHighConvenience for lower doses (500-1,000 mg per capsule)
L-Alanyl-L-Glutamine (Sustamine)HighDipeptide form with improved stability and absorption during exercise

L-Glutamine Powder

Bioavailability: High. Best for: Cost-effective bulk form — dissolves in water; most popular for higher doses.

L-Glutamine Capsules

Bioavailability: High. Best for: Convenience for lower doses (500-1,000 mg per capsule).

L-Alanyl-L-Glutamine (Sustamine)

Bioavailability: High. Best for: Dipeptide form with improved stability and absorption during exercise.

Full L-Glutamine Guide

References

  1. ReviewCieri-Hutcherson NE, Hutcherson TC, Conway-Habes EE, Burns BN, et al. (2019). Systematic Review of l-glutamine for Prevention of Vaso-occlusive Pain Crisis in Patients with Sickle Cell Disease.. Pharmacotherapy. DOI PubMed
  2. RCTHassanein FEA, Mikhail C, Elkot S, Abou-Bakr A (2025). L-arginine vs. L-glutamine oral suspensions for radiation-induced oral mucositis: a triple-blind randomized trial.. Journal of cancer research and clinical oncology. DOI PubMed
  3. RCTLu TL, Zheng AC, Suzuki K, Lu CC, et al. (2024). Supplementation of L-glutamine enhanced mucosal immunity and improved hormonal status of combat-sport athletes.. Journal of the International Society of Sports Nutrition. DOI PubMed
  4. Bloomer RJ, Pence J, Hellenbrand J, Davis A, et al. (2024). Randomized Trial to Assess the Safety and Tolerability of Daily Intake of an Allulose Amino Acid-Based Hydration Beverage in Men and Women.. Nutrients. DOI PubMed
  5. RCTTsujimoto T, Wasa M, Inohara H, Ito T (2023). L-Glutamine and Survival of Patients with Locally Advanced Head and Neck Cancer Receiving Chemoradiotherapy.. Nutrients. DOI PubMed
  6. ObservationalPavel FM, Bungau SG, Tit DM, Ghitea TC, et al. (2023). Clinical Implications of Dietary Probiotic Supplement (Associated with L-Glutamine and Biotin) in Ulcerative Colitis Patients' Body Composition and Quality of Life.. Nutrients. DOI PubMed
  7. Adiamah A, Skorepa P, Weimann A, Lobo DN (2024). Effects of preoperative beta-hydroxy-beta-methylbutyrate, arginine, and glutamine supplementation on outcomes.. Journal of parenteral and enteral nutrition. DOI PubMed
Show 2 more references
  1. Weimann A, Braga M, et al. (2024). Impact of preoperative beta-hydroxy-beta-methylbutyrate, arginine, and glutamine on outcomes.. Clinical nutrition ESPEN. DOI PubMed
  2. Tepaske R, et al. (2022). Evaluation of the recovery after heart surgery following preoperative supplementation with glutamine, arginine, and omega-3 fatty acids.. Nutrition. DOI PubMed