Introduction: why the source of your collagen matters
Why the origin of your collagen counts: type specificity and your goal
Collagen has gone from a niche subject to one of the most popular supplements there is. But faced with the sheer range of products — from bovine to marine, from type I to type II — consumers come up against a basic question. Which source is the right one? The answer is a nuanced one, and it depends on your primary goal. The origin determines which type of collagen the product contains. Processing — hydrolysis — matters at least as much. Only once collagen has been broken down into small peptides can those peptides be absorbed intact from the gut.
The collagen types and where they occur in the body
Three collagen types are the most important here:
- Type I: found mainly in skin, bone, tendons and ligaments. Type I is the most common collagen type in skin, bone, tendons and ligaments, where it forms fibres that contribute to the tissue's tensile strength¹.
- Type II: the most important building block for cartilage — hyaline cartilage — in the joints.
- Type III: found in the skin and in the walls of blood vessels.
Age-related collagen loss as the central problem for regeneration
As the years go by, the body makes less of its own collagen. This steady decline, compounded by external factors such as UV radiation and smoking, leads to visible skin ageing, lower bone density and decreasing elasticity in tendons and ligaments. Fibroblasts (skin), chondrocytes (cartilage) and osteoblasts (bone) each build the collagen matrix of their tissue. Aged skin makes less type I and III collagen. In the lab, skin cells from people over 80 produced less of a collagen precursor than skin cells from 18- to 29-year-olds¹¹. This describes the natural ageing of skin; supplements were not part of it.
Hydrolysis and bioactive peptides
From fibrous protein to bioactive peptide: the hydrolysis process
Intact, raw collagen — as found in broth or gelatine, for instance — is a large protein of some 300,000 daltons, and the body digests it primarily as a simple source of protein. Collagen supplements rest on hydrolysis: an enzymatic process breaks the protein into small fragments, the collagen peptides².
Why molecular weight (the dalton value) is critical
After healthy volunteers took broken-down gelatine (gelatine hydrolysate), collagen fragments such as Pro-Hyp could be detected in their blood, with levels peaking after one to two hours³. Pro-Hyp is made of just two amino acids. The finding shows that part of the collagen reaches the blood as small fragments, not only as single amino acids; what these fragments do in the body was not measured. A commonly cited quality marker is a molecular weight below 2,000 daltons. Di- and tripeptides consist of only two or three amino acids.
Amino acids as signalling agents, and tissue targeting
The discussion centres on a possible signalling function of certain peptides, not just on the quantity of amino acids. The focus is on fragments containing hydroxyproline — prolyl-hydroxyproline and hydroxyprolyl-glycine, for example. After intake these circulate in the bloodstream for several hours and have been detected in the target tissues, where the fibroblasts sit. A review describes the single amino acids from hydrolysed collagen as building blocks for the collagen and elastin fibres of the dermis, the deeper layer of the skin¹. Elastin is a protein that lets the skin stretch. A review summarises studies that have already been published rather than measuring anything itself.
The common collagen sources in detail: type composition and differences
1. Bovine collagen: the all-rounder
Bovine collagen is the most widespread and the most researched source, and it is obtained mainly from the hide, bones and connective tissue of cattle.
Types I and III – skin, bone and muscle
Bovine collagen supplies mainly type I, together with a significant proportion of type III collagen.
- Type I: provides the tensile strength of the dermis, bone and tendons.
- Type III: ensures elasticity and matters for the structure of vessels and organs. In one study, 131 women after menopause with age-related low bone density took 5 g of specific collagen peptides or a dummy product (placebo) every day for 12 months. In the collagen group, bone density at the spine and the hip (femoral neck) rose more than in the placebo group⁴. Bone density shows how much mineral the bone contains; low values are taken as a sign of more fragile bones. One specific product was tested in women with low bone density; the study did not measure whether there were fewer fractures.
Choosing the right molecular weight is decisive for high bioavailability. At the Kollagen Institut you will find hydrolysed collagen peptides: collagen products.
The high glycine and proline content
Bovine collagen has a very high proportion of glycine and proline. Glycine, the smallest amino acid, is not only essential for the formation of collagen but also plays a key part in creatine synthesis. Glycine is therefore one of the amino acids the body draws on for collagen and for creatine alike. In one study, 53 older men with age-related muscle loss (sarcopenia) did strength training for 12 weeks and took either collagen peptides or a dummy product (placebo). With collagen peptides, fat-free mass and leg strength rose more and body fat fell more than with placebo⁵. Fat-free mass is everything except body fat, mainly muscle, bone and water. Only older men with muscle loss who were also training were studied; the study shows nothing about taking it without training.
2. Marine collagen (fish): almost pure type I
Marine collagen is obtained from the skin and scales of fish such as cod and tilapia. It is especially popular in the beauty market.
Pure type I and absorption efficiency
Marine collagen from fish skin, scales and bones consists mainly of type I collagen⁶. Fish collagen is often sold with a small peptide size. In one study, women aged 45 to 60 took hydrolysed fish collagen or a dummy product (placebo) for 12 weeks. In the collagen group, the wrinkle score was then 35% below its starting value, and on the right side of the face wrinkles decreased 24% more than with placebo⁷. The wrinkle score is calculated by a camera system from photos of the face. One specific product was tested; the 35% compares with the start of the study, not with the placebo group.
Environmental considerations and heavy-metal control
Choosing marine sources calls for particular care. Although fish by-products are being used — a form of upcycling — sustainable practice and certification matter, whether the fish is wild-caught or farmed. Rigorous testing for heavy-metal contamination, mercury for instance, is essential. High-quality manufacturers therefore use fish from controlled, clean waters and provide certificates of analysis.
3. Chicken collagen (poultry): the type II source
Collagen from poultry is usually obtained from breast cartilage and supplies mainly type II.
Type II – the main building block of hyaline cartilage
Type II collagen is obtained from chicken cartilage, among other sources; the UC-II preparation, for instance, an unbroken (undenatured) type II collagen, comes from chicken sternum⁸. Type II is thus the collagen type the cartilage matrix itself is built from. Studies on type II preparations accordingly record mostly joint parameters.
How native (undenatured) type II works (UC-II)
Chicken collagen is often also sold as UC-II, undenatured type II collagen, which works through an entirely different mechanism from hydrolysed peptides. UC-II is described as acting via the immune system, through what is known as oral tolerance⁹. This means the immune system gradually reacts less strongly to a substance it takes in regularly through the gut. Clusters of immune cells in the gut wall (Peyer's patches) are thought to be involved. A study in mice with artificially induced joint inflammation (arthritis) examined how this oral tolerance works in the gut and the joint when the animals were given undenatured type II collagen. In the mice without signs of disease, less of two inflammatory messengers (IL-17 and IL-22) was produced in the joints¹³. The body uses such messengers to control inflammation; this was an animal study and does not show whether the same happens in humans.
4. Porcine collagen: economical, and structurally similar
Collagen from pig skin and bone is structurally very similar to bovine collagen and is often used as a lower-cost alternative in Europe and Asia.
Type composition and use
Like bovine collagen, pig collagen supplies mainly type I collagen and is one of the sources of hydrolysed collagen and gelatine². A comparison of gelatine hydrolysates from pig skin, fish skin and fish scales found that the source determines which typical collagen fragments appear in the blood, and how many¹⁴. Only five healthy men took part and only their blood was measured; the study does not show whether the source makes any difference for skin or joints. It is important to bear in mind the cultural and religious restrictions that rule this source out for many consumers.
Quality criteria and safety – what you need to know about your collagen
Purity, transparency and analytical quality
Control of heavy metals and contaminants
The raw materials for collagen come from animal by-products such as skin and bone. Strict control for contamination is therefore of the highest importance. High-quality manufacturers have their products tested in independent laboratories for microbial load, pesticides and above all heavy metals — lead, cadmium and mercury. Only analytically pure products should be consumed.
BSE/TSE risk with bovine collagen
With bovine collagen, the risk of transmitting prions must be excluded — bovine spongiform encephalopathy (BSE), or transmissible spongiform encephalopathies (TSE). In a validation study, the acid and alkali steps used to make gelatine from cattle bone reduced the infectiousness of the BSE agent until it could no longer be detected¹⁷. BSE ("mad cow disease") is a cattle disease whose agent can pass to humans through animal tissue. The study tested this specific process for cattle bone; it says nothing about other processes or raw materials.
Safety through transparency: purity and traceable origin require documentation without gaps. Our collagen is obtained from European raw materials and manufactured exclusively in Germany. You can read the certificates of analysis and quality standards for all the Kollagen Institut's collagen sources — bovine, porcine, fish and chicken: collagen products.
Ethical and sustainable sourcing
Why certified pasture-raised (grass-fed) matters
With bovine and porcine collagen in particular, it is worth looking at where the animals come from and how they were kept.
Upcycling and the circular economy
Collagen production often uses by-products that would otherwise have to be disposed of, such as fish skin and cattle hides. In this respect collagen peptides are an example of upcycling. According to a review, more than 50% of fish tissue ends up as waste, and such leftovers are increasingly being studied as a source of collagen⁶.
Dosing, cofactors and vegan alternatives
Dosing and cofactors
Doses used in studies
In the skin studies analysed by a review, 2.5 g to 10 g of hydrolysed collagen a day was used for 8 to 24 weeks¹². This describes which amounts were studied, not what results those amounts had. The Kollagen Institut daily serving is 2.5–5 g. In one such study, 114 women aged 45 to 65 took 2.5 g of collagen peptides or a dummy product (placebo) daily for 8 weeks before the measurements were taken¹⁵. Comparing with the placebo group shows whether a difference is down to the preparation or would have happened without it.
Vitamin C, the obligatory cofactor
Vitamin C is a cofactor, a partner substance, for two enzymes that chemically modify the precursor of collagen; this is what allows collagen to fold into its stable triple helix¹⁰. Without vitamin C, connective-tissue cells in the lab made less collagen, and it was less cross-linked¹⁶. Cross-linked means the collagen strands are tied to one another, which makes the fibres firm.
Vegan collagen boosters: the alternative for plant-based diets
Since collagen is by definition an animal protein, there is no such thing as genuine vegan collagen. There are, however, collagen-precursor supplements, which aim to support the body's own collagen production.
The precursor strategy
Vegan collagen boosters contain the essential amino acids and cofactors the body needs for its own collagen synthesis:
- Amino acids: proline, glycine and lysine.
- Minerals: zinc and copper, the latter important for the enzyme lysyl oxidase.
- Vitamins: vitamin C, as mentioned above, and vitamin A (retinol); in one study, more collagen precursor was detected after retinol was applied to aged skin¹⁸. The retinol was a lotion put on the skin, not taken by mouth; the study says nothing about vitamin A from food or supplements.
A breakthrough through fermentation
Current research is focusing on producing collagen peptides with the help of genetically modified yeasts and bacteria, through fermentation. In future this technique could deliver genuine, type-specific, structurally identical collagen with no animal components.
Conclusion and what to buy
The myth of the type boom
The choice of source matters, because it determines the dominant collagen type (I, II, III). But what decides how well the body absorbs the peptides is the processing (hydrolysis) and the low molecular weight, ideally below 2,000 daltons. The type boom, cramming numerous collagen types into one product, is often a marketing myth; concentrating on one main type, in pure hydrolysed form, is the simpler approach.
Five points to check before you buy
Apply this checklist when you decide:
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Choose the type: marine and bovine supply mainly type I, chicken mainly type II.
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Check the hydrolysis: look for a stated molecular weight, ideally < 2,000 Da.
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Demand purity: insist on transparency about heavy metal and contaminant testing.
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Traceable origin: look for documented sourcing and production you can actually follow.
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Mind your vitamin C: it contributes to normal collagen formation for the normal function of skin, bones and cartilage, so make sure your diet provides enough.