Glycine

Recovery/Sleep · Evidence: Mixed · Importance: Low

May support sleep quality and relaxation for some users.

What the evidence says

Some support for sleep quality improvement. Mixed evidence overall.

Typical dose & timing

Dose: 3 g before bed.

Timing: 30–60 min before bed.

Role in a stack

Optional sleep support.

Redundancy check:

Cautions & safety

May cause GI discomfort.

Generally safe. Also present in collagen peptides.

Best for

sleep routine · relaxation

Source-verified products

Real products in this category, ordered by review count. Each price and rating comes from the product's own page, recorded 2026-07-29 — follow the link for current values. Links go to the product's source page and never affect this ranking.

• NOW Foods, Glycine, 100 Veg Capsules (1,000 mg per Capsule)
  NOW Foods · $11.62 · 4.8/5 (18785 ratings) · budget tier
• Life Extension, Glycine, 1,000 mg, 100 Vegetarian Capsules
  Life Extension · $12.00 · 4.8/5 (12462 ratings) · mid tier
• Carlson, Glycine Powder, Free Form Amino Acid, 3.53 oz (100 g)
  Carlson · $10.63 · 4.8/5 (5200 ratings) · budget tier
• Thorne, Glycine, 250 Capsules (500 mg per Capsule)
  Thorne · $31.00 · 4.8/5 (2986 ratings) · premium tier
• Solgar, Glycine, 500 mg, 100 Vegetable Capsules
  Solgar · $10.42 · 4.8/5 (2923 ratings) · budget tier
• Source Naturals, Glycine, 200 Capsules (500 mg per Capsule)
  Source Naturals · $16.09 · 4.8/5 (2703 ratings) · mid tier
• Swanson Vitamins, Glycine, 500 mg, 60 Veggie Caps
  Swanson Vitamins · $6.49 · 4.8/5 (1811 ratings) · budget tier
• Nutricost, L-Glycine, 1,000 mg, 120 Capsules
  Nutricost · $15.95 · 4.8/5 (879 ratings) · mid tier
• Nature's Life, Glycine Powder, 14 oz (400 g)
  Nature's Life · $22.39 · 4.7/5 (710 ratings) · premium tier
• Metabolic Maintenance, Glycine Powder, 7 oz (200 g)
  Metabolic Maintenance · $35.00 · 4.8/5 (251 ratings) · premium tier
• Dr. Mercola, L-Glycine, 180 Capsules (500 mg per Capsule)
  Dr. Mercola · $21.99 · 4.8/5 (146 ratings) · premium tier
• Glycine Powder
  NutraBio · $19.99 · 4.8/5 (13 ratings) · mid tier

References

• Glycine improves subjective daytime performance in partially sleep-restricted healthy volunteers. Nutritional Neuroscience (2012)
  Evidence is mixed. Some evidence glycine (3 g before bed) may improve subjective sleep quality and daytime performance. Not a high-priority supplement; effect sizes are small.