Mileage builds endurance, but it also stresses the body. Every stride puts force through tendons, ligaments, cartilage, and bones - connective tissues made largely from collagen, the most abundant protein in the human body. Collagen is built from amino acids like glycine, proline, and hydroxyproline, providing the scaffolding that keeps joints supple, bones resilient, and skin hydrated. As runners, we walk a fine line. Stiff connective tissue improves performance (think springy tendons for efficient force transfer), but it also increases injury risk when tissue repair can’t keep up with training stress. That’s where collagen supplementation is starting to make waves.
Where Does Collagen Come From?
Collagen isn’t a synthetic sports supplement - it’s a naturally occurring protein. We produce it in the body, but also ingest it from animal-derived foods like bone broth, meat, and fish. Supplements use hydrolysed collagen (collagen peptides), broken down into small fragments that the body can absorb. Size matters. Research shows peptides around 2,000 Daltons are absorbed more efficiently - up to 80% compared to larger 5,000 Dalton peptides often used in cheaper products. Smaller peptides reach the bloodstream quickly, where they can stimulate collagen production in joints, skin, and connective tissue.
Benefits of Collagen for Runners
Joint Health & Pain Reduction
Collagen supports cartilage and connective tissue integrity. In a 2023 trial, collagen peptide supplementation improved joint function, pain, and overall outcomes in active adults (PMC10411303). Another study found collagen peptides helped reduce exercise-related joint pain and improved recovery from overuse (PMC8521576). For runners logging heavy mileage, this could mean less stiffness and discomfort, especially in knees and hips.
Recovery from Connective Tissue Injury
Evidence suggests collagen before training may stimulate collagen synthesis and accelerate recovery from tendon or ligament injuries. A 2021 study in Int J Sport Nutr Exerc Metab showed collagen plus vitamin C enhanced rehab outcomes in athletes with ACL injuries. Practical takeaway: 10-15g collagen with ~50mg vitamin C, taken 30–60 minutes before loading or plyometric rehab, may aid repair.
Bone Density & Stress Fracture Protection
Collagen supports bone matrix formation. In postmenopausal women, daily supplementation has been shown to increase bone mineral density and reduce fracture risk over 12 months (König et al., 2018, Nutrients). For runners, especially women at risk of low energy availability, this adds another layer of protection against bone stress injuries.
Skin, Gut & Beyond
- Skin: Collagen supplementation improves elasticity and hydration, countering the decline that comes with age and sun exposure (PMC10411303).
- Gut: Collagen-derived peptides act like prebiotics, strengthening the gut lining and reducing digestive symptoms (PMC9198822).
For runners battling gut stress during training or races, this could be game-changing.
Side Effects and Safety
Collagen is generally well tolerated. The main considerations are:
- It’s animal-derived (usually bovine, porcine, or marine) - not suitable for vegans.
- Mild GI upset is possible in some individuals.
- Safety data is strong, with multiple trials confirming low risk of adverse effects.
How and When to Take Collagen
- Dose: 10-20 g per day is commonly studied.
- Timing: For injury recovery or connective tissue training, take 10g collagen + 50 mg vitamin C 30-60 minutes before exercise.
- For skin/gut support, daily dosing at any time works.
- Form: Choose low-molecular-weight collagen peptides (~2,000 Da) for optimal absorption and efficacy.
Should Runners Take a Collagen Supplement?
If you’re a recreational runner with a balanced diet, collagen isn’t essential. But for those who:
- Train at high mileage or intensity
- Are recovering from tendon or ligament injuries
- Want to protect against age-related joint or bone decline
- Struggle with gut health or skin hydration
…a collagen supplement can be a valuable addition to the toolkit.
The Reality: Where Evidence Is Still Limited
Collagen is one of the most heavily marketed supplements in recent years, and while the science is promising, it’s not unanimous.
Mixed results in endurance performance: While some trials show improvements in joint comfort and recovery, others report minimal changes in running-specific performance. Roberts (2021) notes that outcomes often depend on what’s being measured - strength, pain reduction, or endurance all show different results.
Variability in supplement quality: Many studies use high-quality, low-molecular-weight collagen peptides. Commercial products with larger peptides (5,000 Da) may not deliver the same absorption or benefits.
Small sample sizes: Many trials have fewer than 100 participants, limiting how broadly results can be applied.
Food-first still applies: Collagen is not a substitute for adequate protein intake from whole foods. If your nutrition, sleep, and training plan aren’t dialed in, collagen won’t make up the gap.
In short: Collagen shows real promise for joint, bone, and connective tissue health, but runners should see it as a supportive tool - not a miracle supplement.
FAQs: Collagen for Runners
- Do runners really need collagen supplements? Not all runners do. But if you’re logging high mileage, recovering from injury, or looking for added joint and bone support, collagen can be beneficial.
- What’s the best type of collagen for absorption? Low-molecular-weight collagen peptides (~2,000 Daltons) are significantly more bioavailable than larger 5,000 Dalton molecules.
- Can’t I just drink bone broth? Bone broth contains collagen, but levels are highly variable. Supplements provide a consistent, measurable dose of collagen peptides studied in clinical trials.
- Does collagen improve running performance? Indirectly. Collagen won’t make you faster in steady-state running, but by reducing joint strain, improving recovery, and supporting tendon resilience, it can help you train more consistently - which often leads to better performance over time.
- Are there side effects? Collagen is generally safe and well-tolerated. Mild digestive upset can occur in some, but serious side effects are rare. Those with beef, pork, or fish allergies should check the collagen source.
- Is collagen vegan? No - collagen is animal-derived (bovine, porcine, or marine). Some plant-based “collagen boosters” exist, but they provide nutrients that support collagen production rather than collagen itself.
- Can collagen help prevent injuries? Evidence suggests collagen may support tendon, ligament, and cartilage health, potentially reducing injury risk. But training load management, recovery, and strength work remain the most effective prevention strategies.
- Is collagen safe long-term? Yes. Clinical trials and reviews have found collagen peptides to be safe for daily use over months and even years.
Collagen isn’t a silver bullet. It’s a supportive tool - one that helps connective tissue stay resilient against the repetitive strain of running, while quietly improving recovery, skin, and gut health along the way.