Collagen is everywhere right now – added to coffee, packed into gummies, or sold as a benefit in skincare. It’s touted as the secret to glowing skin, shiny hair and joints that don’t ache. But does collagen really work, or is it just the latest wellness fad with a glossy label?
With women’s health in crisis, it’s no wonder that we’re turning to supplementation as a solution for how we feel – and as many women are deficient in vitamins and minerals such as Vitamin D, B vits and magnesium, there’s no doubt that this can benefit our health. But when it comes to collagen, do we really know what we are dealing with? What does the science actually say – and if you are still keen to try it, what should you actually look for beyond the glossy marketing campaigns?
What is collagen (and why does it matter for our health?)
Collagen is the most abundant protein in the body. It forms the ‘scaffolding’ of our skin, bones, tendons, cartilage and connective tissue. As we age, our natural collagen levels drop and what’s left starts to weaken. Around menopause, this decline accelerates, and many of us begin to notice changes like thinner skin, brittle nails and dry hair, and joints that feel stiffer and ache.
What are the different types of collagen?
There are more than 28 types of collagen, but supplements typically focus on three main ones. Type I collagen is found in skin, tendons and bones. Type III works alongside type I in muscles and blood vessels. Type II is the main component in cartilage, which cushions our joints.
Most supplements use hydrolysed collagen (also called collagen peptides), which has been broken down for better absorption. For joint health, some contain undenatured (which means a substance, typically a protein, is in its natural, unaltered state, without any changes to its structure or conformation) type II collagen, which may work by helping the immune system respond more calmly to cartilage damage.
There’s also marine collagen, which comes from fish and is usually type I. It’s often marketed for skin health due to its smaller peptide size, although research comparing marine and bovine sources is still limited.
Does collagen really work?
…for our skin?
There’s growing interest in collagen supplements for skin, and the early signs are promising, but not definitive. A systematic review and meta-analysis of 26 randomised controlled trials found that oral hydrolysed collagen significantly improved hydration and elasticity in the skin. These results are encouraging, but it should be noted that the trials were mostly short and often funded by supplement companies, which raises questions about their reliability. There was also no difference in the source of the collagen in terms of skin elasticity, or hydration.
Interestingly, a recent review in The American Journal of Medicine conducted a meta-analysis of 23 randomised controlled trials involving 1,474 participants. It found that collagen supplements appeared to improve skin hydration, elasticity, and wrinkles overall. However, when broken down by funding source, only studies funded by pharmaceutical companies showed positive effects. Independent studies showed no benefit. Similarly, high-quality trials showed no significant improvements, while lower-quality ones did. The authors concluded there is currently no reliable clinical evidence to support collagen supplements for preventing or treating skin ageing.
…for joints and movement?
There’s more robust evidence when it comes to joint pain and stiffness. A systematic review from 2025 found that hydrolysed type I collagen helped improve joint pain and mobility, especially in older adults and those with osteoarthritis.
A separate meta‑analysis of 11 randomised controlled trials (870 participants) found that collagen supplements significantly reduced knee pain and improved physical function in people with osteoarthritis, compared to placebo. A third systematic review focused specifically on knee osteoarthritis also confirmed significant pain relief, though its authors cautioned that the certainty of evidence was limited due to small sample sizes and methodological issues, and that all of the trials included were considered to have a high risk of bias.
So what does this tell us about the science behind collagen?
Many of these studies were small and short in duration, which weakens the strength of their conclusions. The studies vary hugely in the type of collagen used (bovine, marine or porcine), the dose given, the presence of co-ingredients like vitamin C and how results are measured, making it hard to compare between studies, too.
Given the concern that some of the trials were sponsored or influenced by supplement manufacturers, it’s important to note that claims and benefits made by companies selling collagen may be based on research that carries the risk of industry bias. This is a well-documented phenomenon where studies funded by companies with a vested interest tend to report more favourable outcomes. Ultimately, this shows the importance of knowing what to look for when purchasing collagen – and being empowered to have informed expectations regarding efficacy and results.
What about HRT for skin, joints, hair and bone health?
If you are considering collagen (or taking it already) during perimenopause to support skin, joints, hair or bones, hormone replacement therapy (HRT) may offer more reliable, evidence-based benefits than supplements alone.
We have oestrogen receptors throughout our body. Changes to our skin during perimenopause – thinning, dryness and wrinkles- are all related to dysfunction of the cells making up the dermal layers such as the keratinocytes and fibroblasts. The findings of oestrogen receptors on these cells suggest that oestrogen deficiency during perimenopause and beyond may be partly responsible for skin aging.
Several randomised controlled trials have shown that oestrogen-based HRT increases skin thickness, collagen content and elasticity. For example, transdermal oestrogen has been found to boost dermal collagen and reduce wrinkles, while a double-blind trial observed a 33% increase in dermal thickness and measurable improvement in collagen levels within six months.
When it comes to our bone health, a 2020 meta-analysis confirmed that HRT consistently increases bone mineral density (BMD) at key sites and lowers fracture risk by 20‑40%. More recent work from Frontiers in Reproductive Health also found that combining HRT with exercise (especially resistance training) yielded the best outcomes for BMD in menopausal women.
Finally, HRT may also support joint health, particularly around menopause when many begin to notice new or worsening aches. The large-scale Women’s Health Initiative trial found that oestrogen-only therapy led to a modest but sustained reduction in joint pain over three years. Other research suggests that oestrogen may help preserve connective tissue and cartilage, potentially reducing inflammation and slowing joint degeneration. While (as ever!) more long-term studies are needed, HRT appears to offer a protective effect for joints during the hormonal transition.
In short, while collagen supplements may offer mild and variable support, HRT addresses the underlying hormonal decline that significantly affects skin, hair, joints and bone. If these areas are a priority for you, it’s worth discussing HRT with your GP.
How is collagen actually absorbed – and what are the concerns?
One of the biggest criticisms of collagen supplements is around how they’re absorbed. Collagen in its whole form is too large to be absorbed by the gut, which is why most supplements use hydrolysed collagen peptides. This means the protein has been broken down into smaller chains of amino acids to help the body take it in more efficiently.
That said, the size of these peptides matters. They’re usually measured in daltons (Da), and a lower molecular weight (under 5,000 Da, ideally closer to 2,000) is generally thought to be better absorbed. The problem is, many popular products don’t list the molecular weight at all, so it’s hard to judge their efficacy. Some experts remain sceptical, arguing that even hydrolysed peptides are just broken down into amino acids like any other protein, and there’s no guarantee they’ll be ‘reassembled’ as collagen in the body.
In short, the science is evolving. Some research suggests hydrolysed collagen does have a unique biological effect, possibly by triggering the body to produce more of its own collagen. But we’re still learning exactly how this works – and which products make the most difference.
What to look for when choosing a collagen supplement
If you’re still thinking of trying a collagen supplement, here are a few key things to check before you buy:
So, should we still buy collagen?
The research so far suggests collagen could show some short term support for skin hydration, elasticity and joint comfort, particularly as we get older. But the research really varies in quality, many studies are short term, and quite a few are funded by companies selling the products.
So if you decide to give it a try and add to your supplementation routine, do so with realistic expectations and a critical eye. Collagen might help – but the strongest results will always come from a combination of good nutrition, regular movement, and a bit of patience with your body.
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