Collagen (Type I, II, III) vs L-Glutamine

Mechanism

Hydrolyzed collagen peptides are absorbed as di- and tripeptides (primarily hydroxyproline-proline and hydroxyproline-glycine) via PepT1 transporters in the small intestine. These bioactive peptides accumulate in skin, cartilage, and bone where they stimulate fibroblast proliferation and extracellular matrix synthesis by upregulating collagen gene expression (COL1A1, COL3A1). They also inhibit MMP (matrix metalloproteinase) activity that degrades existing collagen, and stimulate hyaluronic acid production by dermal fibroblasts.

Standard Dosing

10-20g hydrolyzed collagen peptides daily

Timing

Any time; often added to morning coffee or post-workout shake. For joint support, take with vitamin C 30-60 min before exercise. Type II collagen (undenatured, UC-II) taken on empty stomach.

Cycle Duration

ongoing (minimum 8-12 weeks for visible results)

Side Effects

• Mild bloating
• GI discomfort
• Unpleasant taste
• Rare: calcium elevation (if calcium-containing marine source)
• Feeling of fullness

Contraindications

• Fish/shellfish allergy (if marine-sourced)
• Phenylketonuria (collagen contains phenylalanine)
• Histamine intolerance (bone broth collagen may be high in histamine)

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Mechanism

L-Glutamine is the most abundant amino acid in plasma and skeletal muscle. It is the primary fuel source for enterocytes (intestinal epithelial cells) and rapidly dividing immune cells (lymphocytes, neutrophils). Glutamine maintains intestinal tight junction integrity by modulating tight junction proteins (occludin, claudin-1, ZO-1), preventing intestinal hyperpermeability ('leaky gut'). It serves as a nitrogen shuttle between tissues, is a precursor for nucleotide synthesis (purines and pyrimidines), contributes to gluconeogenesis, and buffers ammonia via glutamine synthetase. During catabolic stress (illness, surgery, intense exercise), glutamine becomes conditionally essential.

Standard Dosing

5-10g daily

Timing

On empty stomach for gut healing. Post-workout for muscle recovery. Dissolves easily in water.

Cycle Duration

8-12 weeks for gut healing; ongoing for maintenance

Side Effects

• Generally well-tolerated
• Bloating at high doses
• Constipation
• Headache
• Theoretical excess glutamate conversion in sensitive individuals (excitotoxicity concern)

Contraindications

• Hepatic encephalopathy (glutamine to glutamate to ammonia conversion)
• Reye's syndrome
• Severe renal failure
• Some cancers are glutamine-dependent (discuss with oncologist)

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