How It Works
Provides specific amino acids (glycine, proline, hydroxyproline) that are rate-limiting for collagen synthesis. Stimulates fibroblasts to produce new collagen. May work via glycine's anti-inflammatory and sleep-promoting effects.
Dosage & Timing
Dosage Guide
Daily Dose10-20 g
TimingAnytime. Often taken with vitamin C (cofactor for collagen synthesis). 30-60 min before bed may improve sleep via glycine.
BioavailabilityHydrolyzed collagen (peptides): ~90% absorption. Undenatured type II collagen works differently — immune-modulating for joints at much lower doses (40mg).
Optimal Timing
Take with food. Consistency matters more than timing for most supplements.
Best Forms (Ranked)
Bovine Collagen (Types I+III) — ★★★★★
Best for skin, hair, nails. Most researched. Our top pick.
Marine Collagen (Type I) — ★★★★☆
From fish. Better absorption claimed. More expensive.
Undenatured Type II — ★★★★☆
For joint health specifically. Much lower dose (40mg). Different mechanism.
Benefits
- Skin elasticity and hydration improvement (8-12 weeks)
- Joint pain reduction (moderate evidence)
- Nail strength and growth
- Gut lining support (glycine)
- Sleep quality (via glycine content)
Side Effects
- Digestive discomfort at high doses
- Fishy aftertaste (marine collagen)
- Not a complete protein — don't count toward daily protein target
✅ Good For
- Skin aging prevention
- Joint pain (especially athletes)
- Gut health support
- Those eating mostly muscle meat (low glycine intake)
- Nail/hair strength
⚠️ Skip If
- Vegetarians/vegans
- Those getting enough glycine from bone broth/whole-animal eating
- Kidney disease (high protein load)