What it is
Hydrolysed collagen is collagen peptides (2 to 5 kDa) obtained by hydrolysing animal collagen (bovine, porcine or marine). It is a food supplement that provides amino acids —mainly glycine, proline and hydroxyproline— and small peptides.
There are trials with modest results for skin elasticity and hydration and for mild joint pain, many funded by manufacturers and of variable quality. It is safe, but expectations need adjusting: it is not a medicine and it does not fill deep wrinkles.
Proposed mechanism
Two pathways are proposed, with evidence that is still limited:
- A supply of the amino acids typical of collagen (glycine, proline, hydroxyproline)
- Dipeptides such as prolyl-hydroxyproline which, in laboratory studies, stimulate fibroblasts
- The real effect in people is modest and takes months to measure
At the counter
When to recommend it
- Skin: elasticity and hydration, with realistic expectations and at least 2–3 months
- Joints: mild pain or stiffness, as an add-on
- Brittle nails (weaker evidence)
- People who want to try it, knowing what to expect
When not to
- Allergy to fish or to the product's animal source
- Vegan or vegetarian diets (it is of animal origin)
- As a replacement for dietary protein
Warnings
- Caution Expectations: small, gradual improvements. It does not remove deep wrinkles.
- Caution Animal origin: check this with vegans or vegetarians and with people allergic to fish (marine collagen).
- Caution There is no evidence that it 'reverses' ageing.
- Caution It is safe, but it is a supplement: it must not delay getting persistent joint pain checked.
Pharmacokinetics
- Absorption
- It is digested into amino acids and small peptides (di- and tripeptides), which are absorbed in the gut. Blood peak at 30–60 minutes.
- Distribution
- The amino acids and peptides spread throughout the body; that they go preferentially to skin or cartilage has not been shown in people.
- Metabolism
- Normal metabolism of dietary proteins.
- Elimination
- Like other proteins and amino acids.
Oral hydrolysed collagen vs topical hyaluronic acid
| Aspect | Hydrolysed collagen (oral) | Hyaluronic acid (topical) |
|---|---|---|
| How it works | Supplies amino acids and peptides | Holds water on the skin's surface |
| Fine lines | Modest improvement (months) | Visible but temporary improvement (hydration) |
| Hydration | Modest | Immediate, on the surface |
| Joints | Modest evidence | Not applicable (topical) |
| Combination | Compatible | Compatible |
They do not compete: one is taken and the other is applied. Neither replaces sunscreen, which is what does most to prevent skin ageing.
Self-assessment
Three questions. When you check your answers you will see the explanation for each one.
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Like any protein, it is digested. What reaches the blood is amino acids and small peptides, some of which stimulate fibroblasts in laboratory studies.
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Studies measure changes from 2–3 months of daily use, and they are modest.
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Trials usually use between 2.5 and 10 g a day for several months. Below that, an effect is hard to expect; above it, there is no proven advantage.
Training content. It does not replace the summary of product characteristics or clinical judgement.