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Joint/Skin

N-Acetyl D-Glucosamine

Also known as: NAG, N-Acetylglucosamine, GlcNAc

C
Evidence

N-Acetyl D-Glucosamine (NAG) is an amino sugar derivative that supports joint cartilage structure and skin barrier function. Evidence for joint health is mixed and moderate, with stronger evidence for gut barrier support.

Primary uses

  • Joint health and cartilage support
  • Skin barrier function
  • Gut barrier integrity
  • Inflammatory response modulation

How it works

  • Provides substrate for glycosaminoglycan synthesis in cartilage matrix
  • Supports mucin production in intestinal lining
  • May modulate immune tolerance through dendritic cell signaling

Dosage

Typical range
500-3000 mg daily
Timing
Can be taken with or without meals; consistent daily dosing recommended
With food
No specific requirement, though may be better tolerated with food
Duration
Most studies examining joint benefits used 8-16 week protocols; effects may require consistent use
Special populations
Generally safe in pregnancy and lactation; limited pediatric data

Forms

  • Powder· 70/100
  • Capsule· 70/100

Safety

Common side effects

  • Mild gastrointestinal upset
  • Nausea
  • Heartburn (rare)

Contraindications

  • Shellfish allergy (some sources derived from shellfish)
  • Severe liver impairment (theoretical concern)

Evidence notes

NAG has shown promise in small studies for joint health, gut barrier support, and inflammatory markers, but larger, well-designed RCTs are limited. Evidence is preliminary and inconsistent, particularly for isolated joint outcomes. Better evidence exists for combinations with glucosamine/chondroitin than NAG alone.

Grade C: Mostly observational or small trials; mechanism is plausible but unproven at scale.

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Medical disclaimer. This page is educational and does not replace advice from a qualified healthcare provider.