Collagen peptides, explained.

1. What collagen is

Collagen is a family of structural proteins. It's the most abundant protein in mammals, making up roughly a third of all the protein in the human body. Where other proteins act as enzymes or messengers, collagen's job is mostly mechanical: it gives tissues strength and shape.

At the molecular level, a collagen molecule is made of three long protein chains wound around one another into a rope-like triple helix. Along each chain, the same pattern repeats over and over: glycine, then two other amino acids, very often proline and hydroxyproline. Glycine is the smallest amino acid, and it's the only one small enough to fit in the tight centre of the helix. That's why collagen contains so much of it.

Your body makes its own collagen from the amino acids it gets from food. That process needs vitamin C, which is one reason a severe vitamin C deficiency (scurvy) shows up as problems with gums, skin and other connective tissue.

2. Types of collagen

Scientists have identified 28 types of collagen, numbered with Roman numerals. A handful account for almost all of it, and type I alone makes up the large majority of the collagen in the body.

Once collagen has been hydrolysed into peptides, the original triple-helix structure is gone. So "type" on a peptide label really describes which tissue the raw material came from and what its amino acid mix looks like. Bovine collagen peptides are usually described as types I and III.

3. Collagen, gelatine and collagen peptides

These three names describe the same protein at different stages of processing. The more it's broken down, the shorter the chains and the more easily it dissolves.

You'll also see "hydrolysed collagen" and "collagen hydrolysate" on labels. Both mean the same thing as collagen peptides.

4. Where collagen supplements come from

All collagen comes from animals. Supplement makers mainly use parts of the animal that the meat and fish industries don't otherwise use, such as hides, skin, scales and cartilage.

• Bovine (cattle). The most common source for unflavoured powders. Usually made from hides. Mostly types I and III.
• Marine (fish). Made from fish skin or scales. Mostly type I. Not suitable for people with a fish allergy.
• Porcine (pig). Common in gelatine and some powders. Not suitable for people who avoid pork.
• Chicken. Usually from sternum cartilage, and the main source of type II collagen products.

5. How to read a collagen label

Collagen products vary more than their similar-looking tubs suggest. Here's what to check.

1. The ingredient list. A plain collagen powder needs just one ingredient. If there are flavours, sweeteners, thickeners or added extras, make sure they're things you actually want.
2. Grams of collagen per serving. Look for an actual number, not just "contains collagen". Watch out for "proprietary blends", which list ingredients but hide how much of each one is in there.
3. The source animal. This matters for allergies and dietary or religious requirements, and a good label states it clearly.
4. Independent testing. Because collagen is made from animal raw materials, reputable makers test each lot for heavy metals and microbial contamination. Ask for a certificate of analysis (CoA). A brand with nothing to hide will share it.
5. The statutory wording. In the UK, a food supplement label must also show the recommended daily dose, a warning not to exceed it, a statement that supplements shouldn't replace a varied diet, and advice to store the product out of the reach of young children. If those are missing, be wary.
6. Molecular weight. Some labels give the average size of the peptides in daltons (Da), often somewhere in the low thousands. Smaller peptides dissolve more easily. Beyond that, treat any big promises about a "special" molecular weight with caution.

6. Collagen as a protein

Nutritionally, collagen peptides are a protein. A 10 g scoop typically provides about 9 g of protein and very little else: no fat, no carbohydrate and only a small amount of sodium.

But collagen is an incomplete protein. It has no tryptophan at all and relatively little of several other essential amino acids. That doesn't make it a bad food. It just means collagen works best as an addition to a diet that already includes complete protein sources such as eggs, dairy, fish, meat, soya, or a combination of pulses and grains.

A collagen scoop adds protein to your diet. It doesn't replace the protein you get from a balanced diet.

Like any protein, collagen peptides are digested in the gut. Most of the peptides are broken down into individual amino acids, and some short fragments of two or three amino acids are absorbed intact. The body then uses these building blocks wherever it needs them, so you can't direct where they end up.

7. What the research says, honestly

Collagen supplements are widely studied, and you'll find plenty of headlines about them. Here's a balanced picture of where that research stands.

• There are many studies, and quality varies. Many trials are small, run for a few weeks or months, and use different products, doses and ways of measuring results. That makes them hard to compare.
• Funding matters. A considerable share of collagen research is funded by ingredient manufacturers. That doesn't automatically make it wrong, but independent replication carries more weight.
• Results are mixed. Some studies report positive findings and others find little or no difference from a placebo. Review articles regularly call for larger, longer, independent trials.
• One product's results don't transfer to another. Studies often test a specific branded ingredient at a specific dose. They don't automatically apply to every collagen product on the shelf.

There's also a legal side. In the UK, foods and food supplements may only carry health claims that have been authorised and added to the GB nutrition and health claims register after a scientific assessment. At the time of writing, no health claims for collagen have been authorised.

That's why we don't claim Kollage Daily does anything specific for your skin, joints, hair or anything else. We sell it as what it verifiably is: a clean, well-labelled protein ingredient. If you have a particular health goal, your GP or a registered dietitian can look at the evidence for your situation.

8. Safety and who should check first

Collagen peptides are a food protein, and at typical serving sizes they're generally well tolerated. Some people notice mild digestive effects, such as a feeling of fullness, especially when they first start using them.

Check with a healthcare professional before using any collagen supplement if you:

• are pregnant or breastfeeding;
• take prescription medication or have a medical condition, particularly one affecting the kidneys or liver;
• have been told to limit your protein intake;
• are allergic to the source animal (beef, fish, chicken or pork, depending on the product).

Choose products tested for contaminants, store them sealed and dry, and keep them out of reach of children. Supplements are intended for adults unless a doctor advises otherwise.

9. Glossary

• Amino acid: one of the building blocks of protein. There are 20 standard amino acids, and nine of them are "essential" because the body can't make them.
• Peptide: a short chain of amino acids. Proteins are long chains, and peptides are short ones.
• Hydrolysis: breaking a chemical bond using water. In collagen production, enzymes speed this up.
• Triple helix: the rope-like structure of three twisted protein chains that is characteristic of collagen.
• Dalton (Da): a unit of molecular mass used to describe how large peptides are.
• Certificate of analysis (CoA): a lab report for a specific production lot, showing test results for things like protein content, heavy metals and microbes.

10. Further reading

For independent UK information on food supplements, nutrition and the rules on health claims:

• NHS: Vitamins and minerals
• Food Standards Agency: Food supplements
• GOV.UK: Great Britain nutrition and health claims register

This guide is general educational information, not medical advice.