Doesn't your body just digest collagen into amino acids?

Mostly yes, but not entirely. Specific dipeptides (proline-hydroxyproline, hydroxyproline-glycine) survive digestion and circulate in plasma — and these appear to signal collagen-producing cells. The mechanism is a mix of amino-acid substrate provision and direct cellular signalling.

Bovine vs marine collagen — which is better?

Bovine is the workhorse — well-studied, cheaper, contains both type I and III collagen. Marine collagen has lower molecular weight peptides (theoretically higher absorption) and is type I dominant — better if your priority is skin specifically. For joint and bone applications, both work; bovine has more trial data.

Why take it with vitamin C?

Vitamin C is a required cofactor for the prolyl and lysyl hydroxylase enzymes that build collagen in your tissues. Most people meet the requirement through diet, but pairing your collagen dose with 250–500 mg vitamin C ensures the substrate isn't bottlenecked by cofactor scarcity.

Updated April 2026Evidence-Based

Hydrolyzed Collagen Peptides

Also known as: Collagen hydrolysate, Collagen peptides, Bovine/marine collagen

Hydrolyzed collagen peptides are short chains of amino acids derived from animal collagen (bovine, marine, or porcine). The hydrolysis process breaks the long collagen protein into 2–5 kDa peptides that are absorbed intact and circulate in the body, where some appear to signal collagen-producing cells (fibroblasts, chondrocytes) to synthesise more endogenous collagen.

How Hydrolyzed Collagen Peptides Works

Specific dipeptides (notably proline-hydroxyproline) survive digestion and circulate intact in plasma. These appear to signal connective-tissue cells via mechanisms separate from being mere amino acid sources. The result is increased synthesis of type I and III collagen in skin and type II collagen in cartilage. The effect is dose-dependent and form-dependent.

Benefits

Skin elasticity: meta-analyses show small but consistent improvements in skin elasticity, hydration, and wrinkle depth with 2.5–10 g/day for 8–12 weeks.
Joint pain: 5–10 g/day modestly improves activity-related joint discomfort, particularly in athletes.
Nail growth: 2.5 g/day reduces nail brittleness over 24 weeks.
Bone density: 5 g/day for 12 months showed small improvements in lumbar spine BMD in postmenopausal women.
Muscle mass: emerging evidence in older adults when paired with resistance training.

Research Summary

Proksch 2014 RCT for skin elasticity. Bolke 2019 RCT for skin properties. Clark 2008 trial for joint pain in athletes. König 2018 trial for bone density. Multiple meta-analyses now confirm small but consistent benefits across these endpoints.

Recommended Dosage

Min effective dose

2.5 g/day for skin/nail; 5 g/day for joint

Max safe dose

20 g/day (well-tolerated in trial use)

Skin/nail/hair: 2.5–10 g/day. Joint support: 5–10 g/day. Bone density: 5 g/day in trial use. Take with vitamin C (250–500 mg) to support collagen synthesis. The hydrolyzed form mixes into coffee, smoothies, and water without thickening; gelatin (non-hydrolyzed) does not.

Side Effects

Generally extremely well tolerated. Mild GI upset is rare. Slightly fishy taste with marine collagen. Allergic reactions possible with bovine or marine sources in users with the corresponding allergies. Some products contain unverified levels of heavy metals — third-party testing matters.

Interactions

No known significant medication interactions. Some concern about kidney load in advanced renal disease — discuss with a clinician if you have CKD.

Frequently Asked Questions

Medical Disclaimer

The content on this page is for informational purposes only and is not intended as medical advice, diagnosis, or treatment. Always consult your physician or qualified healthcare provider before starting any new supplement regimen. Individual results may vary.