Tendon and ligament support

Vitamin C-enriched gelatin supplementation before intermittent activity augments collagen synthesis

Healthy active adults

The protocol increased a collagen-synthesis marker after exercise, making it the most-cited timing study in tendon-support conversations.

It explains why tendon-focused collagen advice often centers on timing and loading instead of passive daily use.

Limitations: Mechanistic and acute; it does not by itself prove clinical tendon healing in injured patients.

Collagen Supplementation Augments Strength Training-Induced Gains in Tendon Size and Rate of Force Development in Elite Female Master Field Hockey Athletes

Elite female master field hockey athletes

Collagen supplementation augmented gains in tendon size and rate of force development during the training block.

Provides a newer training-based tendon paper that feels much closer to the real-world tendon-support narrative than older mechanistic work alone.

Limitations: Highly specific athletic population and protocol; results may not generalize to everyday rehab users.

Impact of Collagen Peptide Supplementation in Combination with Long-Term Physical Training on Strength, Musculotendinous Remodeling, Functional Recovery, and Body Composition in Healthy Adults

19 studies, 768 adults

Review-level evidence supported modest gains in fat-free mass, tendon morphology, maximal strength, and some recovery outcomes when collagen was paired with physical training.

This is the best current single summary for the training-adjunct use case.

Limitations: Certainty ranged from moderate to very low depending on the outcome, especially for tendon mechanics.

Hydrolysed Collagen Supplementation Enhances Patellar Tendon Adaptations to 12 Weeks’ Resistance Training in Middle-Aged Men

20 recreationally active middle-aged men (age 47±5)

Patellar tendon CSA increased more in collagen (+6.8mm²) than placebo (+1.2mm², p=0.027). Stiffness +661 vs +247 N/mm (p=0.009). Young’s modulus also significantly higher.

First RCT showing structural tendon hypertrophy (CSA) from collagen in a recreational middle-aged population.

Limitations: Small sample (n=20). Only patellar tendon. Only men studied.

High-intensity resistance training and collagen supplementation improve patellar tendon adaptations in professional female soccer athletes

11 professional female soccer athletes

Patellar tendon stiffness increased +15.4% (d=0.81) in collagen vs +4.6% in placebo (p=0.002). Young’s modulus +14.2% vs +3.4% (p=0.004).

Evidence in elite female athletes, an under-studied population, showing meaningful tendon stiffness improvements.

Limitations: Very small sample (n=11). Professional athletes may not represent general population.

Hydrolyzed collagen supplementation prior to resistance exercise augments collagen synthesis in a dose-response manner in resistance-trained, middle-aged men

8 resistance-trained men (age 49±8)

PINP AUC significantly higher for 30g (169) than 15g (134) and both higher than 0g (96). Exercise alone did NOT increase PINP in middle-aged men, suggesting connective tissue anabolic resistance.

Establishes a dose-response relationship for collagen synthesis markers, and introduces the concept of connective tissue anabolic resistance in middle age.

Limitations: Very small sample (n=8). PINP is systemic marker, not tissue-specific. Acute response only.

Collagen Peptide Supplementation Enhances Muscle-Tendon Stiffness and Explosive Strength: A 16-Week Randomized Controlled Trial

50 healthy young sedentary males (25 per group)

Achilles tendon stiffness increased significantly in the collagen group (P<0.001, d=0.378). Medial gastrocnemius stiffness also increased (P<0.001, d=0.594). Rate of torque development improved significantly (P<0.001, d=0.525). No changes in muscle or tendon cross-sectional area. No significant changes in placebo group.

Demonstrates that collagen peptides can increase tendon stiffness even in sedentary individuals without structured resistance training, broadening the applicability of tendon-support claims beyond athletes.

Limitations: Sedentary young males only; measured only ankle plantar flexion; unknown generalizability to active, older, or female populations.

Effects of Specific Collagen Peptide Supplementation Combined with Resistance Training on Achilles Tendon Properties

40 healthy male volunteers (age 26.3 ± 4.0 years)

Achilles tendon CSA increased +11.0% in the collagen group vs +4.7% in placebo (P=0.002). Muscle thickness increased +7.3% vs +2.7% (P=0.014). Tendon stiffness and muscle strength increased in both groups with no between-group difference.

Provides direct Achilles tendon morphology evidence complementing patellar tendon studies. The +11% vs +4.7% CSA difference is a meaningful structural adaptation.

Limitations: Young healthy males only; no female participants; no clinical tendon population.

Specific Collagen Peptides Increase Adaptations of Patellar Tendon Morphology Following 14-Weeks of High-Load Resistance Training: A Randomized-Controlled Trial

50 healthy, moderately active male participants

Significantly greater increase in patellar tendon CSA at 60% and 70% of tendon length in collagen group vs placebo. No between-group difference in tendon stiffness or muscle strength (both groups increased similarly).

Confirms patellar tendon hypertrophy from collagen supplementation in a separate research group from the Liverpool studies, adding independent replication.

Limitations: Males only; healthy population only; mechanisms of tendon hypertrophy remain unknown.

The Effect of Specific Bioactive Collagen Peptides on Tendon Remodeling During 15 wk of Lower Body Resistance Training

39 young, healthy, recreationally active men (19 collagen, 20 placebo)

No significant between-group differences in any tendon adaptation. Both groups showed within-group increases in patellar tendon stiffness (CP: +17.3%; PLA: +20.9%), Young's modulus, and decreased elongation/strain. Conclusion: collagen supplementation did not enhance resistance-training-induced tendon remodeling.

Important negative result that provides balance to the evidence base. Raises questions about whether dose (15g vs 5g), peptide specificity, or population factors explain the discrepancy with positive trials.

Limitations: Young healthy males only; contradicts findings from other RCTs using 5g doses, raising questions about dose-response or peptide formulation specificity.

Collagen Supplementation Augments Changes in Patellar Tendon Properties in Female Soccer Players

17 U21 female soccer players (FA Women's Super League, age 17 ± 0.9 years)

Patellar tendon stiffness increased +18.0 ± 12.2% in collagen vs +5.1 ± 10.4% in placebo (P=0.049, d=1.11). Young's modulus increased +17.3 ± 11.9% vs +4.8 ± 10.3% (P=0.035). No change in knee extension strength or muscle thickness in either group.

Extends the Liverpool group's patellar tendon work to younger female athletes in an in-season context. The large effect size (d=1.11) for tendon stiffness is notable.

Limitations: Small sample (n=17); single team/squad; no tendon CSA change detected; unclear whether stiffness improvements translate to injury reduction.

Oral Supplementation of Specific Collagen Peptides Combined with Calf-Strengthening Exercises Enhances Function and Reduces Pain in Achilles Tendinopathy Patients

20 adults with chronic mid-portion Achilles tendinopathy

VISA-A score improved by 12.6 points (95% CI: 9.7-15.5) in collagen-first group at 3 months vs 5.3 points (95% CI: 2.3-8.3) in placebo-first group. After crossover, improvements tracked with active supplement in both groups.

The only RCT testing collagen in a clinical tendinopathy population rather than healthy volunteers. Demonstrates clinical relevance beyond biomarkers and structural measurements.

Limitations: Small pilot study (n=20); crossover design with potential carryover effects; published 2019 but remains the only Achilles tendinopathy-specific collagen RCT.

Does Additional Dietary Supplementation Improve Physiotherapeutic Treatment Outcome in Tendinopathy? A Systematic Review and Meta-Analysis

6 RCTs, 241 participants with tendinopathy

Supplementation plus physiotherapy significantly improved pain reduction (SMD=-0.74, 95% CI -1.37 to -0.10, P<0.05). No significant improvement in functional outcomes when supplementation was added. Collagen-specific studies included TENDOFORTE for Achilles tendinopathy and hydrolyzed collagen type I with ESWT.

Review-level evidence that dietary supplementation (including collagen) can reduce pain in clinical tendinopathy populations when added to physiotherapy.

Limitations: Only 6 studies met inclusion criteria; small total sample; heterogeneous supplement compositions; limited to tendinopathy populations.