What is bioavailability?
The nutrients in our food are broken down into smaller molecules first in the stomach and then in the intestinal tract. Once some of the molecules are small enough, they can be absorbed across the wall of the intestine into the bloodstream.
In this frame, bioavailability refers to how accessible a nutrient is within the food, to which extent it is “freed” broken down from the food matrix, transported and absorbed into the bloodstream.
The more bioavailable a dietary supplement, the more efficiently it is absorbed, triggering several health benefits.
That’s why bioavailability is a crucial characteristic for any nutraceutical manufacturer: a poorly bioavailable dietary supplement offers very scarce added value to the consumer.
What is bioactivity?
The term bioactivity refers to the ability of a small molecule to modulate a biological function of a target cell and/or tissue, for example a bioactive peptide which is a small fragment of protein. During digestion, a peptide needs to be released from a “parent” protein in order to be bioactive. A peptide can exert a peculiar ‘biological activity’ once it has entered the bloodstream, acting on a target tissue.
Bioactivity is what makes a nutrient beneficial.
Most of the nutrients you’re familiar with (such as protein-derived peptides and vitamins) might be bioactive.
So any nutritional supplement that claims to have some kind of benefit for joint health, bone health, skin beauty and sports recovery needs to demonstrate that it can indeed be taken up by the body and remain bioactive in the bloodstream, reaching its target tissue in the body.
Collagen peptides: proven bioavailability and bioactivity
The health benefits of collagen peptides are well-known. There are numerous studies demonstrating their efficacy. A recent study (published in December 2019) has expanded our understanding of how and why collagen peptides are so effective. The main benefits are hinged on their bioavailability and bioactivity. As mentioned, these are two of the most important elements of delivering benefits to the end-user.
Let’s take a closer look at the biological mechanism:
Collagen peptides are a mix of short-chain peptides consisting of two to twenty amino acids. Once taken up, collagen peptides go through important modifications in the body. Digestive enzymes break down these chains into smaller pieces (e.g. di- and tripeptides), easily absorbable by the body and measurable in the blood after collagen peptide supplementation.
An increased level of dipeptides in the blood was observed after oral Peptan intake. The two most abundant dipeptides in collagen supplements are hydroxyproline-glycine (Hyp-Gly) and proline-hydroxyproline (Pro-Hyp), well-known for their bioactivity . For example, in case of skin beauty, cells in specific skin layers are stimulated to produce water-binding hyaluronic acid increasing the level of moisture in the skin.
More and more people around the world are consciously looking for natural ways to support their joints, bones and skin health. More and more people are actively engaged in sports and intense training and are becoming aware of the importance of sports recovery. As we’ve seen, collagen peptides can be an effective nutritional solution for those consumers. So, with the mounting scientific evidence, collagen peptides are leading the way in these markets.
 Kleinnijenhuis, A.J., 2019. Non-targeted and targeted analysis of collagen hydrolysates during the course of digestion and absorption. Anal Bioanal Chem. 2019 Dec 24. doi: 10.1007/s00216-019-02323-x.
 Ohara, H., et al., 2010. Collagen-derived dipeptide, proline-hydroxyproline, stimulates cell proliferation and hyaluronic acid synthesis in cultured human dermal fibroblasts. The Journal of Dermatology, 37(4), 330–338. doi: 10.1111/j.1346-8138.2010.00827.x
 Asai, T. T. et al., 2019. Food-Derived Collagen Peptides, Prolyl-Hydroxyproline (Pro-Hyp), and Hydroxyprolyl-Glycine (Hyp-Gly) Enhance Growth of Primary Cultured Mouse Skin Fibroblast Using Fetal Bovine Serum Free from Hydroxyprolyl Peptide. International Journal of Molecular Sciences, 21(1), 229. doi: 10.3390/ijms21010229