Collagen for strength training: what are its effects on muscles and tendons?

The role of collagen in muscles, tendons, and joints

Collagen is a family of proteins that provide structure and mechanical strength to many tissues, particularly tendons, which contain large amounts of it and transmit force from muscles to bones, but also ligaments, cartilage, and the sheaths surrounding muscle fibers. Muscle is therefore more than just the proteins that produce its contraction: its connective tissue also contributes to support and force transmission.

When you consume collagen, digestion breaks it down into amino acids and small fragments called peptides, some of which enter the bloodstream, but ingested collagen does not travel directly to a tendon as collagen ready to be put in place. The body uses the absorbed components in its normal functions, and their presence in the circulation alone does not prove a benefit for a joint or muscle. This is the distinction to keep in mind when collagen for athletes is presented as an obvious solution: this protein’s natural role in the body explains why it is studied, but only human research can assess what the supplement actually provides.

Does collagen help build muscle and strength?

Favorable results, but several different things are being measured

Trials combining collagen and exercise have observed additional gains in certain measures of body composition or performance, as shown by a meta-analysis published in 2024 that included 19 studies and 768 participants. It found, among other things, a favorable effect on fat-free mass and a small average effect on maximal strength, with varying certainty across outcomes. However, fat-free mass includes more than muscle fibers, since water and other nonfat tissues are also part of it. This means that not all of the gain can be attributed to muscle capable of contracting, especially when trials use different methods and comparators.

A 2026 study helps explain this distinction: among 29 men who completed 12 weeks of strength training, taking 15 g of specific peptides daily led to a greater increase in type I collagen within the muscle compared with a placebo. This finding concerns its supporting tissue and does not, on its own, demonstrate greater hypertrophy of contractile fibers or injury prevention; the study was partly funded by the peptide manufacturer.

Why collagen does not replace whey

Collagen provides plenty of glycine and proline, but its amino acid profile is less suited to building contractile proteins than a complete protein such as whey, particularly because it is low in leucine and, when used alone, does not provide a balanced source of all essential amino acids. In a 2023 trial, 45 young adults received 30 g of whey, 30 g of collagen, or a placebo after a strength training session: over the following five hours, only whey significantly increased contractile protein synthesis compared with the placebo. This experiment does not predict all long-term outcomes, but it shows why two powders that provide protein are not interchangeable.

If your main goal is to build muscle, start by reviewing your meals and your daily protein intake: eggs, dairy products, soy, or other suitable food sources can meet this need; a powder mainly serves to fill any gaps.

Our guide to the benefits of whey for strength training explains when it can be convenient.

Collagen for tendons: training adaptations and tendinopathies

What studies show about tendons subjected to exercise

Research on collagen for tendons looks in particular at their size and how they deform under load: the “stiffness” measured in these experiments describes their resistance to elongation, rather than a feeling of painful stiffness upon waking.

In the trial published by Nulty and colleagues in 2025, participants trained their lower limbs twice a week for 12 weeks; those who received 30 g of hydrolyzed collagen with 50 mg of vitamin C after each session achieved greater improvements in certain properties of the patellar tendon compared with a placebo containing the same vitamin C. No additional benefit for muscle or strength gains was observed, and the trial did not measure injuries. These results suggest a plausible benefit as an addition to training, without establishing that collagen protects someone who trains against a rupture or tendinopathy. A 2026 systematic review also highlights the variety of doses, exercises, and measurements used, as well as the very limited representation of women in the included trials.

Collagen and tendonitis: what do we know when pain is already present?

The term “tendonitis” remains common, but tendinopathy is often used to describe tendon pain associated with loading, without assuming that inflammation explains the entire situation. This does not mean that the same diagnosis or management can automatically be applied to elbow pain during pull-ups and Achilles tendon pain.

A trial involving 20 patients with chronic midportion Achilles tendinopathy combined exercises with 2.5 g of specific peptides twice daily or a placebo; after three months, the groups switched supplements for another three months, with a favorable signal on a score combining symptoms and function. This small pilot trial, funded by the manufacturer, does not demonstrate that collagen cures tendonitis: exercises accompanied the use of a specific formulation, and both their effects and those of the supplement could persist after the groups switched.

For this form of Achilles tendinopathy, the 2024 clinical guidelines prioritize progressive loading exercises. If pain persists, returns with every session, or makes you change your movement, assessing its cause and adjusting your training therefore come before purchasing a supplement. Any supplementation should remain an addition discussed within that framework, without serving as a justification for continuing to increase loading despite symptoms.

What are the potential benefits for sports-related joint pain?

Joint pain is a different issue from adaptations in a healthy tendon, as illustrated by a trial published in 2021 in which active young adults with activity-related knee pain received 5 g of specific peptides daily or a placebo for 12 weeks, with improvements in certain pain scores favoring collagen. Reduced discomfort may be useful for someone who trains, but it proves neither cartilage reconstruction nor a treatment for all causes of knee pain, and it also does not justify assuming that another collagen product, taken at a different dose, will produce the same result. Any potential benefit must be assessed based on the actual situation and changes in symptoms, alongside their management.

How much collagen should you take, for how long, and when?

The doses studied depend on the goal and the product

There is no daily collagen dosage for strength training validated for all uses, because amounts cannot be compared without considering the formulation, how often it is taken, and the desired outcome.

Situation studied	Protocol	Key points
Achilles tendinopathy — Praet, 2019	2.5 g of specific peptides twice daily; a three-month period with collagen within a total six-month program.	Pilot trial with exercises; not a general prescription for all tendinopathies.
Activity-related knee pain — Zdzieblik, 2021	5 g of specific peptides daily for 12 weeks.	Effect on symptoms, without evidence of cartilage reconstruction.
Patellar tendon adaptation — Nulty, 2025	30 g of collagen and 50 mg of vitamin C after each of the two weekly sessions, for 12 weeks.	Intake was tied to the sessions: this was not 30 g every day.
Intramuscular collagen — Jerger, 2026	15 g of specific peptides every day during 12 weeks of strength training.	Measurement of connective tissue within the muscle.

These protocols describe experiments, not a guarantee of results, and also show why occasional intake does not reproduce trials conducted over several weeks, without justifying a routine “course” for everyone who trains.

Before or after exercise, with or without vitamin C?

The suggestion to take collagen before training is based in particular on the idea of making its amino acids available when the tissue is being loaded, a hypothesis examined in a 2017 study involving eight men who consumed vitamin C-enriched gelatin one hour before a jumping activity; researchers monitored blood markers and conducted experiments on laboratory-engineered ligaments. This protocol does not demonstrate that taking it before exercise is better than taking it afterward, especially since other trials have observed adaptations with post-workout supplementation.

Vitamin C does contribute to collagen production, but its biological role does not prove that adding more improves outcomes in someone whose needs are already met, and trials in which both groups received it cannot isolate its additional benefit.

If you choose to supplement, favor a protocol consistent with the goal discussed and a routine that is easy to follow, since the available data do not justify requiring everyone to take it on an empty stomach or within a window of a few minutes around the session.

How do you choose collagen for strength training?

The best collagen for an athlete cannot be determined solely by the words “marine,” “type I,” or “peptides,” and the label should first allow you to identify what you are actually taking:

• the animal source and allergens;
• the form of collagen and the amount per serving;
• other ingredients, particularly in blends;
• the manufacturer’s identity and any available traceability or testing documentation;
• the match between the product sold and the one used in a study when a scientific finding is highlighted.

Hydrolyzed collagen is broken down into smaller peptides, but this processing alone does not guarantee a clinical effect. Bovine, porcine, and fish-derived collagen can provide amino acids and peptides that are absorbed; a small 2024 comparative study measured this absorption without assessing muscle gains or tendon health, so it does not justify choosing marine collagen for strength training on the basis of proven superiority for these outcomes. Hydrolysates must also be distinguished from undenatured type II collagen preparations studied for certain joint-related issues, at different amounts and with a different approach: a dose in milligrams of the latter formulation cannot be directly compared with several grams of hydrolyzed peptides.

The source also matters for your dietary choices: bovine, porcine, and marine collagen are still animal-derived, including when the product is sold as peptides.

Can you combine collagen, whey, and creatine?

Mixing whey and collagen in the same drink allows you to take them together, but does not turn collagen into a complete protein: if you reduce the amount of whey to replace it with collagen, you change the serving’s amino acid profile; if you add it, you simply increase what the blend provides. A trial published in July 2026 compared whey alone, collagen alone, a combination of the two, and a placebo over eight weeks in 40 trained men. A combination of 30 g of whey and 10 g of collagen daily produced better results on several measures. However, each group contained only ten participants, muscle mass was estimated using bioelectrical impedance analysis, and, above all, the blend provided more protein than whey alone: this comparison is not enough to prove a synergy specific to collagen.

Creatine works differently, supporting the reserves used to repeat short, intense efforts, so combining creatine and collagen may serve two distinct goals, without a specific additional benefit of their combination having been established by the research examined here. The guide to the effects and use of creatine details its benefits independently of collagen.

Side effects and precautions to know

Short trials cannot rule out all side effects, particularly rare or long-term ones. In a four-week trial of a porcine hydrolysate, no serious events were reported, but one person reported nausea when starting supplementation; this does not allow a frequency common to all formulations to be inferred. Allergies deserve particular attention: serious reactions after ingesting fish collagen, including hydrolyzed collagen, have been described, since hydrolysis or a powdered form does not guarantee the absence of allergenicity. A fish allergy should therefore prompt you to seek advice before using marine collagen, and combining it with whey adds the issue of milk proteins.

If you have kidney disease, a prescribed protein restriction, or are pregnant or breastfeeding, seek professional advice before adding a supplement, because the absence of data suited to these situations should not be replaced by a promise of safety; precautions concerning protein intake are particularly important when kidney function is already impaired.

Finally, examine the entire formula: the risks of a product containing several active ingredients are not the same as those of collagen alone, and our article on dietary supplements for strength training helps put each product in the context of its purpose, rather than adding more supplements without an identified need.

Sources and use

Editorial research verified on November 5, 2026. The protocols described do not constitute individual prescriptions.

• Aussieker et al., 2023. Collagen Protein Ingestion during Recovery from Exercise Does Not Increase Muscle Connective Protein Synthesis Rates. Acute comparison of whey, collagen, and placebo after strength training.
• Bischof et al., 2024. Meta-analysis on collagen, training, body composition, and recovery. Overall results and certainty of the evidence.
• Jerger et al., 2026. Trial on intramuscular type I collagen. Connective tissue, daily protocol, and partial funding from Gelita.
• Nulty, Phelan, and Erskine, 2025. Trial on patellar tendon adaptations. Intake after the two weekly sessions; no specific funding declared.
• Praet et al., 2019. Pilot trial on Achilles tendinopathy. Symptoms and function with exercises; Gelita funding, also documented by the University of Canberra portal.
• Chimenti et al., AOPT/JOSPT, 2024. Guidelines on midportion Achilles tendinopathy. Terminology and the role of loading exercises.
• Zdzieblik et al., 2021. Trial on knee pain in active young adults. Specific peptides, 5 g/day for 12 weeks.
• Virgilio et al., 2024. Crossover study of the absorption of different collagen hydrolysates. Digestion, circulating peptides, and limitations of source comparisons.
• Jäger et al., ISSN, 2017. Position stand on protein and exercise. Protein quality and prioritizing dietary intake.
• Shaw et al., 2017. Vitamin C-enriched gelatin before intermittent activity. Hypothesis of pre-exercise intake and limitations of experimental markers.
• Martínez-Puig et al., 2023. Collagen Supplementation for Joint Health: The Link between Composition and Scientific Knowledge. Distinction between formulations; review used for composition, not as evidence of a universal benefit.
• Seyhan et al., July 2026. Trial on the combination of whey and collagen. Favorable signal and comparison limitations; no funding declared.
• Kreider et al., ISSN, 2017. Position stand on creatine. Creatine’s own role, without evidence of synergy with collagen.
• Clinical Nutrition, 2025. Four-week controlled trial of a porcine hydrolysate in adults with overweight or obesity. Tolerability data, without extrapolation to sports performance.
• Buchalski et al., 2026. Systematic review of tendon outcomes and performance. Heterogeneity and limitations on generalizability; the authors’ characterization of the evidence is not treated as clinical certainty.
• Fujimoto et al., 2016. Case of anaphylaxis after ingestion of hydrolyzed fish collagen. Documented allergy risk, without an estimate of frequency.
• Anses, 2025 opinion, referral 2023-SA-0216. Substances authorized in dietary supplements and conditions of use. Precautions concerning protein in cases of kidney impairment.