Biotin, collagen, beauty supplements: do hair and skin need them?

Biotin gummies. Collagen powders. Hair growth capsules. Beauty drinks. Red-light masks. Peptides. Biohacking gadgets promising to turn back the clock. We are constantly being told there is a new way to look younger, grow thicker hair and achieve glowing skin. To be honest, who wouldn't be tempted?

There is nothing wrong with wanting to look and feel your best. But before spending another £40 on a tub of “hair, skin and nails” supplements, it is worth asking a more useful question: what does my body actually need?

Healthy hair and skin are not the result of one magic ingredient. They result from complex processes that require adequate energy, protein, vitamins, minerals, hormones, and a healthy internal environment.

Sometimes a supplement can genuinely help. But if you are already getting enough of something, taking more doesn't necessarily make your body produce more beautiful hair or younger-looking skin.

So let's look at two of the biggest stars of the beauty-supplement world: biotin and collagen.

Biotin: the famous hair vitamin that may not be the answer

Biotin, also known as vitamin B7, has become almost synonymous with healthy hair. Search for “hair growth” online, and you will quickly find biotin gummies, capsules and drinks promising stronger, thicker, shinier hair. The problem is that the evidence doesn't really support the idea that healthy people need high-dose biotin for better hair.

True biotin deficiency is uncommon. Biotin is found in foods including eggs, meat, fish, nuts, seeds and some vegetables, while certain gut bacteria can also synthesise it. A review of the evidence found that the published research supporting biotin supplementation for hair growth is remarkably limited in people without deficiency (Patel et al., 2017).

Recent evidence reaches a similar conclusion: biotin supplementation might not help prevent hair loss in people who are biotin-sufficient. Biotin supplementation has been found useful when there is an underlying deficiency or specific medical condition (Morris et al., 2026). So if your hair is suddenly shedding more, becoming finer, or refusing to grow as it used to, I wouldn't make a tub of biotin gummies your first port of call; I would ask why.

Your hair may be telling you that resources are limited, and I see this often in women who are trying very hard to “eat clean,” lose weight, or stay slim as they move through their 40s and beyond.

They may be eating very “healthily”: plenty of salads, vegetables, nuts and seeds, smoothies, and good supplements, but simply not eating enough. Hair is not an essential organ. Your body will prioritise nourishing the brain, heart and other vital functions over producing luxurious hair. If energy, protein, iron, or other nutrients are in short supply, the body has to choose where those resources go. Hair growth can be one of the first things to suffer.

This matters because hair loss can have many potential causes. Iron status is one area worth investigating: a systematic review and meta-analysis involving more than 10,000 participants found that women with nonscarring alopecia had significantly lower ferritin levels than controls (Treister-Goltzman, Peleg and Yarza, 2022).

Thyroid function is another factor to consider, as thyroid hormones directly influence hair-follicle biology, including the growth phase of the hair cycle (van Beek et al., 2008). A recent study of 500 women with telogen effluvium (AKA severe hair loss) found that hypothyroidism (slow thyroid) was associated with it (Bin Dayel et al., 2024).

So the bigger question is: are you actually nourished enough to support hair growth?

If you are experiencing persistent hair loss, it can be much more useful to investigate iron status, thyroid function, B12, folate and other relevant nutritional markers, alongside your diet, menstrual history, weight changes, stress, medications and digestive health, than simply adding another supplement.

Where digestive symptoms, malabsorption or gut problems are suspected, more targeted functional investigations and tests may also be appropriate. Consider that if you don't absorb food well, you won't absorb any of the supplements you are taking either. The point is to find the reason rather than guess the remedy or buy a supplement you have seen advertised on social media.

And then there is collagen…

If biotin is the queen of hair supplements, collagen is undoubtedly the queen of the anti-ageing world.

Collagen powders and drinks are everywhere, often accompanied by photographs of impossibly youthful influencers telling us that their skin has been “transformed”. But there is an important distinction between “collagen may have benefits” and “this powder will make you look 10 years younger.” The latter is marketing.

When you consume collagen, your digestive system does not simply transport a scoop of collagen from your stomach directly into your skin. Collagen is a protein. It is digested into amino acids and smaller peptides, some of which can be absorbed and circulate in the body. These peptides may have biological effects, including influencing fibroblasts and extracellular processes involved in skin structure (Iwai et al., 2005; Ricard-Blum, 2011). 

And this is where things get interesting. Research does suggest that hydrolysed collagen peptides can improve some measures of skin health, particularly hydration and suppleness. A 2023 systematic review and meta-analysis of 26 randomised controlled trials involving 1,721 participants found considerable improvements in skin hydration and skin elasticity following hydrolysed collagen supplementation, although the authors also highlighted differences between studies and the need for larger, better-designed trials (Pu et al., 2023).

So collagen isn't necessarily snake oil, but it's not a time machine either.

Where does the collagen actually go?

Your body constantly makes, breaks down, and rebuilds collagen, and it isn't exclusively about your skin.

Type I collagen is an important structural protein in skin, bones, tendons, ligaments and other connective tissues. Your body will use the amino acids and peptides available to it according to its physiological requirements. This is one reason I personally find collagen supplementation more interesting from a joint and connective-tissue perspective than as an anti-ageing miracle.

There is also growing interest in how individual genetics influence collagen biology.
For example, variants in COL1A1, the gene encoding the alpha-1 chain of type I collagen, have been associated with differences in bone mineral density and fracture risk in some populations (Grant et al., 2005; Keen et al., 1999). Research has also investigated collagen-related genetic variants in relation to bone health.

That doesn't mean that discovering a COL1A1 variant automatically tells you that you need collagen supplements. Genetics rarely works that simply, but it illustrates an important point: we are not all biochemically identical. And this is where personalised nutrition becomes much more interesting than taking whatever supplement happens to be trending on Instagram.

What about genetics and beauty?

Your genes don't determine everything about your hair and skin, but genetic variations can influence how you metabolise and utilise nutrients, how you react to environmental stressors and how certain biological pathways function.

Vitamin B12 is a good example. Severe B12 deficiency can be associated with dermatological manifestations including hyperpigmentation, changes in hair, glossitis and cheilitis (Kaur et al., 2018; Kumar, 2026). Rare inherited disorders or SNPs (genetic variations) affecting B12 metabolism could also produce skin and hair manifestations.

This does not mean everyone with dry skin or thinning hair needs a genetic test, but it does mean that, in the right person, interpreting genetic variants alongside symptoms, diet and functional testing can provide another piece of the puzzle.

For me, that is the exciting part of personalised nutrition. Rather than asking, “Which supplement should I buy?” we can ask, “What is happening in my body, and what support does it actually need?”

Food still beats the supplement shelf

There is another beauty intervention that is remarkably unglamorous: eating enough, and eating a varied diet.

Adequate protein provides amino acids needed for tissue maintenance and repair. Iron, zinc, selenium, iodine, B vitamins, vitamin C, vitamin A, and essential fatty acids all play a role in maintaining normal physiological processes relevant to skin and hair.

Vitamin C, for example, is required for normal collagen formation. Protein provides the amino acids from which your body makes its own proteins. A varied diet also provides thousands of plant compounds and other nutrients that you simply cannot reproduce by taking a handful of capsules.

And don't underestimate hydration and overall skin care either. A diet rich in minimally processed foods, plenty of colourful plants, adequate protein and healthy fats – together with sufficient fluid intake, sleep, movement and sensible sun protection – will do considerably more for your long-term health than randomly stacking beauty supplements.

So, should you take biotin or collagen?

My answer is: it depends.

Biotin makes sense when there is a genuine reason to suspect or establish inadequate biotin status. But taking high-dose biotin simply because your hair is thinning is unlikely to tackle the underlying problem, and high doses can also interfere with certain laboratory tests, potentially producing misleading results (Morris et al., 2026).

Collagen is more nuanced. Reasonable evidence suggests collagen peptides can modestly improve measures such as skin hydration and firmness. If you enjoy taking collagen and it fits into your diet and budget, there may be a place for it, but I certainly wouldn't use it as a substitute for investigating why your skin or hair has changed in the first place.

The beauty supplement I would invest in first? Information. If your hair is falling more than usual, becoming noticeably finer or losing its quality, investigate it. If your skin has suddenly become dry, dull or unusually reactive, investigate it. If you are exhausted, losing or gaining weight unintentionally, or struggling with digestive symptoms, investigate those things too.

Rather than spending hundreds of pounds experimenting with supplements, consider working with a qualified nutritional professional who can look at the bigger picture and, where appropriate, use blood, functional or genetic testing to identify nutritional insufficiencies, potential deficiencies and individual factors that may be affecting the way you look and feel.

References

Bin Dayel, S., Hussein, R.S., Atia, T., Abahussein, O., Al Yahya, R.A. and Elsayed, S.H. (2024) ‘Is thyroid dysfunction a common cause of telogen effluvium?: A retrospective study’, Medicine, 103(1), e36803. doi: 10.1097/MD.0000000000036803.

Grant, S.F.A. et al. (2005) ‘Common variants at the PCOL2 and Sp1 binding sites of the COL1A1 gene and their interactive effect influence bone mineral density in Caucasians’, Human Molecular Genetics, 14(16), pp. 2265–2270.

Kaur, P. et al. (2018) ‘Dermatologic findings of vitamin B12 deficiency in infants’, Pediatric Dermatology, 35(5), pp. 584–589. doi: 10.1111/pde.13679.

Keen, R.W. et al. (1999) ‘Association of polymorphism at the type I collagen (COL1A1) locus with reduced bone mineral density, increased fracture risk, and increased collagen turnover’, Arthritis & Rheumatology, 42(2), pp. 285–290.

Morris, A. et al. (2026) ‘Effectiveness of biotin supplementation for hair growth in patients with alopecia: a systematic review’, Dermato, 6(2), 17.

Patel, D.P., Swink, S.M. and Castelo-Soccio, L. (2017) ‘A review of the use of biotin for hair loss’, Skin Appendage Disorders, 3(3), pp. 166–169.

Pu, S.-Y. et al. (2023) ‘Effects of oral collagen for skin anti-aging: a systematic review and meta-analysis’, Nutrients, 15(9), 2080. doi: 10.3390/nu15092080.

Treister-Goltzman, Y., Peleg, R. and Yarza, S. (2022) ‘Iron deficiency and nonscarring alopecia in women: systematic review and meta-analysis’, Skin Appendage Disorders, 8(2), pp. 83–91. doi: 10.1159/000519952.

van Beek, N. et al. (2008) ‘Thyroid hormones directly alter human hair follicle functions: anagen prolongation and stimulation of both hair matrix keratinocyte proliferation and hair pigmentation’, Journal of Clinical Endocrinology & Metabolism, 93(11), pp. 4381–4388. doi: 10.1210/jc.2008-0283.

Kumar, N. (2026) ‘Revisiting the hematological manifestations of vitamin B12 deficiency’, Frontiers in Nutrition.