Collagen
protein
Key Takeaways
- Meta-analysis of 19 RCTs found hydrolyzed collagen improved skin after 90 days (pmid:33742704)
- A 2025 meta-analysis found benefits disappeared in high-quality/independently funded studies (pmid:40324552)
- Meta-analysis of 11 RCTs showed improvement in knee OA pain and function (pmid:39212129)
- Native and hydrolyzed collagen have different mechanisms (pmid:36986062)
- No FDA daily value; collagen is a protein supplement
Evidence Spectrum
15 studies reviewed →Bone health
Type I collagen is essential for bone mineralization, but oral supplementation evidence for bone outcomes is limited.6
15
Studies Reviewed
water-soluble
Solubility
Role in the Body
Collagen is the most abundant protein in the human body (~30% of total protein). It is the main structural component of connective tissues. Type I collagen is most prevalent, essential for bone mineralization and skin integrity. Collagen synthesis requires vitamin C as a cofactor. Production naturally declines with age. Oral supplements are available as hydrolyzed collagen (peptides) or native type II collagen, each with different proposed mechanisms.
- Structural integrity of skin, bones, cartilage, tendons, and ligaments
- Bone mineralization scaffold (Type I)
- Wound healing and tissue repair
- Maintains skin elasticity and hydration
Supplement Forms
Hydrolyzed collagen (peptides)
RecommendedBioavailability: 0%
Most studied form for skin and joints
Native (undenatured) type II collagen
RecommendedBioavailability: 0%
Immune-mediated mechanism; 10-40 mg/day for joints (pmid:36986062)
Gelatin
Bioavailability: 0%
Partially hydrolyzed; less studied
Food Sources
Bone broth
Chicken skin and connective tissue
Fish skin
Gelatin Based foods
Vitamin C Rich foods support endogenous synthesis
Deficiency
Prevalence: Not applicable. Production declines with age. Genetic mutations cause osteogenesis imperfecta (pmid:26542481).
Risk Factors:
- Aging
- Vitamin C deficiency
- Excessive UV exposure
Safety & Interactions
Possible Side Effects:
- • Generally well tolerated
- • Occasional mild GI discomfort
- • Unpleasant taste in some formulations
Drug Interactions:
- • No significant drug interactions reported
Contraindications:
- • Allergy to source material (bovine, marine, porcine)
- • Fish/shellfish allergies for marine-sourced products
Frequently Asked Questions
Do collagen supplements work for skin?
Mixed results. 2021 meta-analysis found positive effects, but 2025 analysis found benefits disappeared in high-quality/independently funded studies.
Which collagen type is best for joints?
Both hydrolyzed and native type II collagen show benefits for OA through different mechanisms.
Can you get enough collagen from food?
Your body synthesizes collagen from amino acids and vitamin C. Adequate protein and vitamin C intake supports production.
Research Sources
15 peer-reviewed studies analyzed from PubMed. 7 directly cited in this review.