Why I Recommend Collagen: A Registered Nutritionist’s Guide to Collagen Supplements

If you’ve searched “best collagen supplement UK” or “do collagen supplements actually work?”, you’re not alone.

Collagen supplements are one of the most popular wellness products right now, promising better skin, stronger joints, improved bone health and even thicker hair.

As a Registered Nutritionist, I’m often asked whether collagen supplements are worth it.

My answer?
Sometimes, and strategically.

Collagen isn’t a miracle anti-ageing powder. But in the right context, it can be a useful addition for joint health, bone support, skin integrity and even as a targeted protein top-up.

Here’s why I recommend collagen and how to choose the best collagen supplement.

What Is Collagen And Why Does It Matter?

Collagen is the most abundant protein in the body. It provides structural support to:

• Skin
• Joints and cartilage
• Bones
• Tendons and ligaments
• Hair and nails (indirectly)

According to clinical studies and skin ageing research:

• Collagen production peaks in early adulthood (late teens to early 20s).

• After age 25, the body makes less collagen each year.

• By age 40, the body is estimated to produce about 30–35% less collagen than at age 18!

• Loss continues progressively with age, particularly after menopause when hormonal changes accelerate collagen breakdown.

Why I Recommend Collagen for Joint Health

This is where the strongest research exists.

A 24-week double-blind, placebo-controlled trial found that 10g of collagen hydrolysate daily significantly reduced joint pain in athletes compared to placebo (Clark et al., 2008).

A meta-analysis of randomised controlled trials also suggested collagen supplementation can positively affect joint pain, particularly in osteoarthritis (Porfírio & Fanaro, 2016).

Cartilage is made up of a collagen framework that provides strength and elasticity, alongside proteoglycans that retain water and help absorb shock. With ageing and repetitive mechanical stress, collagen fibres in cartilage gradually degrade, reducing resilience and increasing discomfort. Hydrolysed collagen provides key amino acids – glycine, proline and hydroxyproline – that are required for collagen synthesis, and some research suggests collagen peptides may stimulate cartilage-producing cells to increase collagen and extracellular matrix production.

Who I commonly recommend it to:

• Active individuals
• Those with early osteoarthritic discomfort
• Peri- and post-menopausal women
• Clients recovering from injury

Collagen and Bone Health

Bone isn’t just calcium.

Around 90% of bone’s organic matrix is Type I collagen. Think of collagen as the flexible framework that minerals bind to.

Without adequate collagen scaffolding, bone becomes more brittle.

Emerging research suggests collagen supplementation may:

• Support bone mineral density
• Stimulate osteoblast (bone-building cell) activity
• Reduce markers of bone breakdown

Evidence is promising, particularly in postmenopausal women, though long-term trials are still ongoing.

Collagen for Hair and Nails – What’s the Reality?

The marketing here is strong, the science is more modest.

There is limited high-quality evidence that collagen directly stimulates hair growth. However:

• Collagen provides amino acids needed to form keratin (the protein in hair and nails)
• If someone’s overall protein intake is low, collagen may indirectly support hair strength and nail resilience

One small uncontrolled study suggested collagen peptides may reduce nail brittleness and improve nail growth (Hexsel et al., 2017), but it lacked a placebo group.

In practice, many of my clients notice:

• Stronger nails
• Less nail splitting
• Reduced hair shedding

Collagen as a Protein Addition, But Not a Complete Protein

Collagen is protein, but it’s not a complete protein.

It is rich in:

• Glycine
• Proline
• Hydroxyproline

But it is low in other essential amino acids, particularly tryptophan.

That means:

✔ It can be a useful protein top-up
✔ It can support connective tissue
✘ It should not replace whole protein sources like eggs, fish, meat, tofu or legumes

If someone struggles to hit their daily protein target, collagen can contribute, but it should be part of a balanced intake, not the sole source. In addition, it is taste free (if you get the right brand and quality!) and easy to add in to your diet. Just 2 tbsp can get you 10g of protein! So as long as you are consuming alongside other protein rich foods, it can be a nice addition.

How to Choose the Best Collagen Supplement According to a Nutritionist

Quality matters enormously.

When choosing the best collagen supplement, I recommend looking for:

• Hydrolysed collagen (collagen peptides) for better absorption
• Type I & III for skin and bone
• Type II for joint support
• Third-party testing for heavy metals and contaminants
• No artificial sweeteners or unnecessary fillers
• Sustainable and traceable sourcing

If it’s bovine collagen, I recommend checking that it is grass-fed and pasture-raised, if it’s marine collagen, ensure it’s from responsibly sourced fish.

Collagen Supplements I Recommend as a Nutritionist

When recommending collagen, I prioritise quality above all else, including sourcing, testing, and how well a product is tolerated day-to-day. If it’s bovine, I look for grass-fed and pasture-raised; if it’s marine, I want responsibly sourced fish and clear heavy metal testing.

Taste and smell is SO important to me, I can’t stand when a collagen has a strong smell or flavour.

My go-to brand for clients and my own use is Ancient and Brave (I have been using their collagen for over 5 years!) and swear by it for my hair and nail growth – I literally have to chop off my hair every month when I take it regularly. Check out their TRUE collagen which is from Bovine sources or WILD for their fish based collagen.

How to Take Collagen Supplements for Best Results

Collagen requires consistency.

Most studies run for at least 8-12 weeks, so daily intake is pretty key.

Dosage I Recommend:

• Minimum: 5g daily
• Optimal: 10g daily – 2 heaped tablespoons

Do You Need Vitamin C?

Yes and no. Vitamin C is essential for collagen synthesis, but you can cover this in your diet.

My concern around collagen with added vit c is it is harder to use. Vitamin C is heat sensitive, so you wouldn’t want to add it to coffee or hot drinks, which is how I typically recommend adding in collagen (makes it so easy and a great habit stack if you already enjoy a hot drink!)

When and How to Take Collagen Supplements

Collagen can be taken with or without food.

To maintain consistency, I suggest habit stacking:

• Add to morning coffee/matcha
• Stir into matcha
• Blend into smoothies
• Mix into yoghurt
• Mix into collagen fudge, my go-to sweet treat recipe
• Bake into banana bread or cookies

Because of its glycine content, it can be a nice one to include before bed to support better sleep, so you could add it to a hot cacao, but to be honest, include it in whichever way helps you keep consistency with it.

Who Should Avoid Collagen Supplements?

Collagen is generally very safe and well-tolerated.

However:

• Avoid if allergic to fish (marine collagen) or beef (bovine collagen)
• Those with histamine intolerance may react to some collagen products
• Individuals with kidney disease should check with their GP due to protein load
• Always seek professional advice if pregnant, breastfeeding or on medication

Final Thoughts: Why I Recommend Collagen Supplements

I don’t recommend collagen to everyone. When I see 20-year-olds taking it because of the whole girl glow brigade, I do think it is a little pointless. I am all for starting your anti-ageing protocols early to be preventative, but in your 20’s, most of you just don’t need it – just hit that adequate protein and vit C instead.

But I do recommend it strategically for:

• Adults over 35
• Peri- and post-menopausal women
• Active individuals
• Those recovering from injury
• Clients struggling to meet protein targets

Remember, collagen doesn’t stand alone as a miracle fix and works best when combined with:

• Adequate dietary protein
• Strength training
• Vitamin C intake
• Good sleep
• Stress regulation

It’s a supportive tool, not a shortcut.

If you’re unsure whether collagen is right for you, you can book a personalised consultation and free discovery call here.