An easily dissolved protein powder used to support skin, joints, bone, and connective tissue as the body's own collagen declines with age. Evidence is strongest for modest skin improvements; bone, muscle, and joint signals are promising or mixed. Inexpensive and notably safe, with benefits clearest when paired with exercise, protein, and vitamin C. (Full Review)
| Marker | Target | Why |
|---|---|---|
| Serum calcium | 9.2–10.0 mg/dL | Detect additive hypercalcemia from high-calcium marine collagen plus other calcium sources |
| Estimated kidney filtration rate (eGFR) | >90 mL/min/1.73 m² | Confirm kidneys comfortably handle added protein load |
| 25-hydroxy vitamin D | 40–60 ng/mL | Supports bone and collagen synthesis and gives context for any calcium changes |
| High-sensitivity C-reactive protein (hs-CRP) | <1.0 mg/L | Track systemic inflammation relevant to joint outcomes |
| 24-hour urinary oxalate (stone-formers only) | <40 mg/24 h | Screen the theoretical oxalate load in recurrent calcium-oxalate stone-formers |
Cadence: Baseline draw; optional recheck at ~3 months if using high-calcium products or if a condition warrants; then every 12 months