What is a Peptide, Can You Digest and Absorb Collagen?

What is a Peptide, Can You Digest and Absorb Collagen?

What is a Peptide, Can You Digest and Absorb Collagen? 

Let’s talk about collagen being used as a post-workout protein powder and for supporting skin and joint health. Can your body absorb a collagen peptide and do collagen peptides really have a targeted effect on the body or are they just digested into individual amino acids the same as any protein chain? Below we address some common misconceptions that various social media “experts” are sharing about collagen peptides. 

If you want to hear a real expert's explanation and dive deep into the science, check out this podcast


Collagen Is Not Absorbed By The Body 

This just simply is not true! This would mean that your body was not performing its digestion duties correctly and the appearance of your stool would be cause for concern. In actual fact, collagen may improve mild digestive symptoms and reduce bloating (1)  

So, how does your body digest and absorb a peptide in general? A peptide is a chain of amino acids that is smaller than a protein chain, amino acids make up both proteins and peptides. When a chain of amino acids (either in a supplemental form or after chewing and swallowing a steak for example) enters the stomach it is denatured by Hydrochloric Acid and the enzymatic digestion process begins. What remains then travels to the small intestine where different enzymes complete the digestion by breaking down the chains into amino acids, dipeptides, and tripeptides. The remaining amino acids, dipeptides, and tripeptides are then absorbed for distribution and use as your body sees fit. Collagen peptides have high digestibility and bioavailability meaning all amino acids are absorbed and used by the body. 

Collagen Peptides Will Be Broken Down When They Are Absorbed and Have No “Targeted Benefits” 

Also, not exactly true! Collagen peptides are very special in that 50% of the structure is made of the amino acids proline and glycine. When these two amino acids unite, the bond is extremely strong. This means that the chains are not completely split into their individual amino acids, there will be some dipeptides and tripeptides among other individual amino acids. And as we have already mentioned, all of these forms can be absorbed through the small intestine. Proline forms kinks in collagen chains and as they become long and thin they form a shape that ensures at least 10% of the collagen peptide will be absorbed with a specific sequence of amino acids. This is why we call collagen peptides, specific collagen peptides, or bioactive collagen peptides as the 10% that is absorbed in a specific shape is bioactive that can benefit the body in specific ways. The type of collagen peptide including it’s molecular weight will determine what specific sequence is absorbed and what part of the body will benefit from it. Randomised control trials using these specific collagen peptides on real-life humans can shed more light on this. 


Collagen Works - But The Type Of Collagen Matters

Not all hydrolysed collagen is the same!!! Hydrolysed collagen peptides are made from their parent source (marine, bovine etc) and the process in which they are made will be the difference between having a biological effect or not. The measures (temp, ph, and other controls) that are taken during the hydrolysis process to ensure a specific and consistent molecular weight are very important. It is also important that the company creating the bioactive peptide undergoes rigorous testing to ensure the end product has a specific molecular weight and follows this up with randomised control trials testing the specific peptide to see if it has the desired effect within the human body, such as increasing lean muscle mass, skin or joint health. Not all hydrolysed collagen peptides will do the same thing, there is no one size fits all option. 

A great example of the type of collagen being important is when you compare two recent studies looking into joint pain and collagen benefits. A 2020 study by Bongers (3), took a group of 167 physically active and healthy individuals for 12 weeks to determine if supplementing with collagen could reduce knee pain. The participants were split into two groups, one group received the collagen protein which was a 5g dose with a molecular weight of 2kdaltons and the other received a placebo. It was concluded that collagen had no beneficial effects. Whereas a similar study in 2021 by Zeidzieblik et al (4), consisting of 180 active participants also used a 5g dose but with fortigel collagen peptides which are a molecular weight of 3kdaltons (indicating a different peptide structure) and they found a statistically significant reduction on activity-related knee joint pain.

ATP Science - Why We Choose GELITA as Our Collagen Supplier

The collagen that we use here at ATP Science is sourced from GELITA, a company that is industry-leading and implements the rigorous testing standards we just mentioned as well as having the clinical trials to back up their bioactive collagen peptides and specific effects. This is why we can say with confidence that we believe in our products, we know they are digested, absorbed, and used for a targeted effect in the body. 

BodybalanceⓇ Collagen Peptide - Post-workout support

Multiple studies now show that 15g of the Bodybalance specific collagen peptide when taken within 1 hour of a resistance training session can help to increase lean body mass, and muscle mass and stimulate and boost collagen production of the skeletal muscle (5,6,7,8,9,10,11). Yes, there are other studies out there showing no benefit, but please read them carefully as they are using 60g of collagen protein at different times of the day potentially displacing amino acid balance.(12) More is not best, a balanced diet with adequate protein including resistance training followed by a 15g dose is what the literature has found to be best. We do acknowledge that a study published in 2019 suggests that up to 36% of the protein in the diet can be supplemented with collagen protein while maintaining amino acid balance 

VerisolⓇ Collagen Peptide - Skin Support

This particular collagen peptide has randomised controlled trials supporting its ability to increase elastin and collagen for improving cellulite and reduction in eye wrinkles as well as increasing pro-collagen Type 1 and elastin. (13,14)

FortigelⓇ and TendoforteⓇ Collagen Peptides - Joint support

Tendoforte works to improve the function of ligaments and tendons and Fortigel can improve mobility and knee pain in healthy active individuals by increasing the collagen components of cartilage. (15,16,17,18)

The Take Home

Bioactive collagen peptides truly are amazing, they can be digested and absorbed and the research is showing that specific types can have targeted effects in the body for increasing lean muscle mass, skin, and joint health. If you are hearing otherwise you might like to check the qualifications of the person you are listening to - are they a nutritionist or specialist in this area and have they considered the latest research? 


  1. Abrahams M, O'Grady R, Prawitt J. Effect of a Daily Collagen Peptide Supplement on Digestive Symptoms in Healthy Women: 2-Phase Mixed Methods Study. JMIR Form Res. 2022 May 31;6(5):e36339. doi: 10.2196/36339. PMID: 35639457; PMCID: PMC9198822.
  2.  Bongers CCWG, Ten Haaf DSM, Catoire M, Kersten B, Wouters JA, Eijsvogels TMH, Hopman MTE. Effectiveness of collagen supplementation on pain scores in healthy individuals with self-reported knee pain: a randomized controlled trial. Appl Physiol Nutr Metab. 2020 Jul;45(7):793-800. doi: 10.1139/apnm-2019-0654. Epub 2020 Jan 28. PMID: 31990581.
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  5. Oertzen-Hagemann V, Kirmse M, Eggers B, Pfeiffer K, Marcus K, de Marées M, Platen P. Effects of 12 Weeks of Hypertrophy Resistance Exercise Training Combined with Collagen Peptide Supplementation on the Skeletal Muscle Proteome in Recreationally Active Men. Nutrients. 2019 May 14;11(5):1072. doi: 10.3390/nu11051072. PMID: 31091754; PMCID: PMC6566884.
  6. Kirmse M, Oertzen-Hagemann V, de Marées M, Bloch W, Platen P. Prolonged Collagen Peptide Supplementation and Resistance Exercise Training Affects Body Composition in Recreationally Active Men. Nutrients. 2019 May 23;11(5):1154. doi: 10.3390/nu11051154. PMID: 31126103; PMCID: PMC6566878.
  7. Jendricke P, Centner C, Zdzieblik D, Gollhofer A, König D. Specific Collagen Peptides in Combination with Resistance Training Improve Body Composition and Regional Muscle Strength in Premenopausal Women: A Randomized Controlled Trial. Nutrients. 2019 Apr 20;11(4):892. doi: 10.3390/nu11040892. PMID: 31010031; PMCID: PMC6521629.
  8. Zdzieblik D, Jendricke P, Oesser S, Gollhofer A, König D. The Influence of Specific Bioactive Collagen Peptides on Body Composition and Muscle Strength in Middle-Aged, Untrained Men: A Randomized Controlled Trial. Int J Environ Res Public Health. 2021 Apr 30;18(9):4837. doi: 10.3390/ijerph18094837. PMID: 33946565; PMCID: PMC8125453.
  9. Khatri M, Naughton RJ, Clifford T, Harper LD, Corr L. The effects of collagen peptide supplementation on body composition, collagen synthesis, and recovery from joint injury and exercise: a systematic review. Amino Acids. 2021 Oct;53(10):1493-1506. doi: 10.1007/s00726-021-03072-x. Epub 2021 Sep 7. PMID: 34491424; PMCID: PMC8521576.
  10. Balshaw TG, Funnell MP, McDermott E, Maden-Wilkinson TM, Abela S, Quteishat B, Edsey M, James LJ, Folland JP. The effect of specific bioactive collagen peptides on function and muscle remodeling during human resistance training. Acta Physiol (Oxf). 2022 Nov 25:e13903. doi: 10.1111/apha.13903. Epub ahead of print. PMID: 36433662.
  11. Oikawa SY, Kamal MJ, Webb EK, McGlory C, Baker SK, Phillips SM. Whey protein but not collagen peptides stimulate acute and longer-term muscle protein synthesis with and without resistance exercise in healthy older women: a randomized controlled trial. Am J Clin Nutr. 2020 Mar 1;111(3):708-718. doi: 10.1093/ajcn/nqz332. Erratum in: Am J Clin Nutr. 2020 Dec 10;112(6):1656. PMID: 31919527; PMCID: PMC7049534.
  12. Oral Supplementation of Specific Collagen Peptides Has Beneficial Effects on Human Skin Physiology: A Double-Blind, Placebo-Controlled Study. Proksch E., Segger D., Degwert J., Schunck M., Zague V., Oesser S. Skin Pharmacol Physiology, August 2013
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  15. L. Carpenter, J.B. Peel, M.R. Carpenter, J. Lowndes, T.J. Angelopoulos and J.M. Rippe Annals of the Rheumatic Diseases 2005;64(Suppl 3):1544. Session: Osteoarthritis – Clinical aspects and treatment June 2005. EFFECTIVENESS OF A COLLAGEN HYDROLYSATE-BASED SUPPLEMENT ON JOINT PAIN, RANGE OF MOTION AND MUSCLE FUNCTION IN INDIVIDUALS WITH MILD OSTEOARTHRITIS OF THE KNEE: A RANDOMIZED CLINICAL TRIAL.
  16. Bruyère, O., Zegels, B., Leonori, L., Rabenda, V., Janssen, A., Bourges, C., and Reginster, J. 2012. Effect of collagen hydrolysate in articular pain: a 6-month randomized, double-blind, placebo controlled study. Complement. Ther. Med. 20: 124–130. doi:10.1016/j.ctim.2011.12.007. PMID:22500661.
  17. 2019 Jun; 11(6): 1249. Published online 2019 May 31. doi: 10.3390/nu11061249 Human Enriched Serum Following Hydrolysed Collagen Absorption Modulates Bone Cell Activity: from Bedside to Bench and Vice Versa. Fabien Wauquier,1,2 Audrey Daneault,1,2 Henri Granel,1,2 Janne Prawitt,3 Véronique Fabien Soulé,4 Juliette Berger,5 Bruno Pereira,6 Jérôme Guicheux,7,8,9 Gael Y. Rochefort,7 Nathalie Meunier,10 Adeline Blot,10 and Yohann Wittrant.