What it is
Mechanism evidence: human
At a glance
What it is, why people use it, the evidence, and what to know before trying it.
Why people use it
- Fewer or shallower wrinkles (often crow’s feet / eye-wrinkle volume).
- Higher skin elasticity (cutometer R2/R5/R7).
- Higher skin hydration (corneometer) and/or lower transepidermal water loss.
- Higher dermal collagen density (ultrasound echogenicity).
- Less OA pain (VAS, WOMAC pain).
- Better OA function / stiffness (WOMAC, KOOS).
- Activity-related joint comfort in athletes without radiographic OA.
- Cartilage structure improvement (MRI / dGEMRIC), not just symptoms.
- Greater tendon cross-sectional area and/or stiffness when combined with loading.
- Higher collagen synthesis around exercise (PINP).
Evidence at a glance
Hydrolyzed type I/III collagen peptides are a **real, absorbable, incomplete protein**. Hyp-containing dipeptides reach human plasma. That is not the same as rebuilding a face, a knee, or a tendon. **What the evidence supports, narrowly.** A **small-to-moderate** reduction in **OA symptom scores** (pain SMD about −0.35, ~8.5 mm on a 100-mm VAS; VAS WMD about −17 mm in an older mixed-form meta) over 12–24 weeks at **5–10 g/day**, in a literature that still mixes peptide hydrolysate with undenatured type II and is softer on WOMAC pain/function subscores. **Tendon CSA** can increase beyond training alone at **5 g/day SCP** in two Freiburg RCTs, or stiffness can rise at **30 g + vitamin C** in small independent loading studies (n=17 and n=20) — **surrogates, not injury outcomes**. **Skin** has many positive RCTs and two positive metas (de Miranda 2021; Pu 2023) at **2.5–10 g** for 8–12 weeks, almost all in women, **almost all industry-tied**.