Everything you need to know about collagen.
Everything You Need to Know About Collagen
Collagen has exploded in popularity across health and beauty, appearing in everything from skincare to supplements. If you're still wondering what the fuss is about, this is your complete, honest guide — what collagen actually is, the different types, how to support it naturally, what damages it, and how supplements really work (minus the marketing gloss). For the deep dive on the supplement side, our complete guide to liquid marine collagen picks up where this leaves off.
What Is Collagen?
Collagen is the most abundant protein in the body — often called the "glue" that holds you together, because it's found throughout your connective tissue: ligaments, tendons, muscles and skin, as well as teeth, corneas and blood vessels. It makes up about a third of your body's total protein, which is exactly why it's so central to how your skin, joints and structure hold up over time.
The Main Types of Collagen
There are many types of collagen; here are the four you'll hear about most:
- Type I — by far the most prevalent (around 90% of your collagen), made of densely packed fibres. It gives structure to skin and supports bone, and it's the type most relevant to skin, hair and nails.
- Type II — the main component of cartilage, so it's key for your joints and skeletal system. Its fibres are more loosely packed.
- Type III — supports the structure of muscles, organs and arteries.
- Type IV — found in the layers of skin and a key part of the "basement membranes," helping with filtration between layers.
Worth knowing: marine collagen (the kind in Kollo) is rich in Type I — the most abundant type in skin and bone — which is why it's a popular choice for skin-focused goals.
How to Support Your Collagen Naturally
All collagen starts as procollagen, which your body builds by combining the amino acids proline and glycine — a process that requires vitamin C. So the most natural way to support collagen is to eat well for it:
- Vitamin C — citrus, bell peppers, strawberries, blackcurrants, broccoli. (It's a required cofactor for collagen formation, which is its genuine, authorised role.)
- Proline — egg whites, dairy, mushrooms, cabbage, asparagus.
- Glycine — found in many protein-rich foods, plus skin-on meats and gelatine.
- Copper — lentils, cashews, sesame seeds, cocoa, organ meats.
- Quality protein overall — seafood, meat, poultry, dairy, tofu and legumes supply the amino acids your body needs to build new proteins.
What Damages Your Collagen?
Collagen naturally declines with age, but some factors speed it up — and these are genuinely worth knowing:
- Sun exposure — UV is one of the biggest drivers of collagen breakdown in skin, which is why daily SPF is one of the best "anti-ageing" habits there is.
- Smoking — reduces collagen production and damages existing collagen and elastin.
- A very high-sugar diet — over time, excess sugar contributes to glycation, a process linked to skin ageing. It's one factor among many rather than a reason to panic about any single meal, but a balanced diet supports skin generally.
Food Sources vs Supplements
Animals have collagen in their connective tissue too, so natural food sources include bone broth (made by simmering bones) and skin-on fish, chicken and pork. If you'd prefer a consistent daily option, supplements are the other route — and here's how they differ:
Most collagen supplements are either hydrolysed collagen (collagen peptides) or gelatine. Hydrolysed collagen is broken into smaller peptides, which makes it easier to mix and digest — it's the form used in most research, including Kollo. If you'd like to understand the terminology, our guide on marine collagen peptides vs hydrolysed collagen breaks it down, and liquid collagen vs powder compares formats.
Supplements also differ by source: bovine collagen comes from cattle, while marine collagen comes from fish and is rich in Type I. Both can be effective; marine is a popular choice for skin-focused goals.
What Does the Evidence Actually Show?
Let's be precise here, because this is where marketing tends to run ahead of the science:
- Skin — strong evidence. A 2023 meta-analysis of 26 randomised trials found collagen peptides improved skin hydration and elasticity versus placebo.
- Joints — promising. A 2023 meta-analysis found collagen modestly reduced knee osteoarthritis-related pain. Note: that's modest symptom relief, not "protection from arthritis developing" — we won't claim the latter.
- Muscle — only with training. Some research (in older adults) found collagen peptides combined with resistance training improved body composition — but collagen isn't a complete protein and won't build muscle on its own. The training does the work; collagen supports connective tissue.
Do Collagen Supplements Have Side Effects?
Collagen is generally well tolerated, with no commonly reported serious side effects — but "well tolerated" isn't the same as "suitable for everyone," so the honest caveats matter. Marine collagen comes from fish, so anyone with a fish or shellfish allergy should avoid it, and it isn't suitable for vegetarians or vegans. As with any supplement, check with your GP first if you're pregnant, breastfeeding, on medication or managing a health condition. It's also worth knowing what to avoid when taking collagen supplements.
Collagen at a Glance
| Question | The honest answer |
|---|---|
| What is it? | The body's most abundant protein — structural scaffolding |
| Best-evidenced benefit | Skin hydration and elasticity |
| Also promising | Joint comfort (modest); nails |
| Support it naturally with | Vitamin C, protein, proline, glycine, copper |
| What harms it | Sun, smoking, ageing, a very high-sugar diet |
Choosing a Supplement
- Look for hydrolysed peptides — the form used in most research.
- Choose a studied dose — Kollo provides 10g; see why 10g is the researched dose.
- Be consistent for 8–12 weeks — that's the timeframe studies use.
- Check certifications — Kollo is Informed Choice certified, independently screened.
- Wondering when to start? See what age to start taking collagen.
Featured Product
Premium Liquid Marine Collagen
10,000mg of clinically studied Naticol marine collagen daily - for visibly smoother, firmer, more hydrated skin in as little as 28 days.
Shop Now →The Bottom Line
Collagen is genuinely fascinating — the most abundant protein in your body and a big part of why your skin, joints and structure hold up over the years. You can support it through a balanced, nutrient-rich diet and by protecting it from sun and smoking, and supplements offer a consistent extra route, with the strongest evidence for skin and promising support for joints. Cut through the hype and it's a straightforward, useful supplement — we'll always tell you which claims are solid and which aren't.
If you'd like to try it, Kollo's 10g daily sachet of Naticol® marine collagen — with vitamins B1, B5, B6, B12 and C and the amino acid l-lysine — makes it easy to stay consistent. Our complete guide to liquid marine collagen goes deeper, our collagen powder guide compares formats, our joint supplements guide covers mobility, and for women thinking about it all together in midlife, our women's wellness guide for over 40s ties it together.
Kollo Health was co-founded by Jenni Falconer - TV presenter, Smooth Radio breakfast host, ten-time London Marathon runner and host of the RunPod podcast. Read her story and why she created Kollo.
