Why I Stopped Recommending Supplements for Skin. And Then Changed My Mind.

For a long time, the honest pharmacist's answer about skin supplements was: mostly nonsense.

Not unkindly, and not without reason. Walk into any health food shop or browse any wellness brand's website and you will meet the kind of claims that make a pharmacist's eye twitch: "glowing skin in 30 days", "visibly younger in weeks", "the secret your dermatologist is not telling you." A healthy scepticism about anything marketed with that much confidence and that little cited evidence is well earned.

So for years, the sensible advice when patients asked about supplements for skin was: sort out your diet, your sleep, and your hydration first. The rest is probably expensive urine. That foundation still holds. But the rest of the picture has been updated by the evidence, and this post walks through it, category by category.

What changes a clinician's mind: the research, not the marketing

The case for some supplements has strengthened, not because anyone found a product they liked, but because the clinical trial data, particularly on hydrolysed collagen peptides (broken-down protein fragments the body can absorb) and specific micronutrients, turned out to be more rigorous than expected. The evidence is not overwhelming. But it is not nothing either.

That is a meaningful distinction. A lot of wellness products have no plausible reason to work AND no decent evidence. Some skin supplements have a plausible reason to work AND at least some decent evidence. Those are two very different situations, and they were too often treated as the same. Being evidence-led means updating when the evidence changes.

Collagen peptides: more interesting than expected

Collagen is the most abundant protein in skin, making up roughly 75% of its dry weight. After the mid-twenties, the skin produces less of it each year. By perimenopause, oestrogen decline makes this more noticeable, because oestrogen supports collagen production, and when levels drop, skin can feel thinner and lose some firmness. The question is whether eating or drinking collagen does anything for the collagen in your skin.

The short answer: probably yes, in some people, with caveats. The collagen in supplements is hydrolysed into smaller fragments called collagen peptides (short chains of amino acids, the building blocks of protein). Taken orally, they are absorbed from the gut into the bloodstream. Some research suggests these peptides may reach skin tissue and encourage fibroblasts (the cells that produce collagen) to increase their output. Several randomised controlled trials have found improvements in skin hydration, elasticity, and wrinkle depth with regular supplementation over 8 to 12 weeks. The effect sizes are modest, and the studies are often funded by supplement companies, which matters and should make you cautious. But the research is there, and the proposed reason it could work is credible.

The caveat: if your diet already contains adequate protein, collagen peptides are not providing a unique benefit that a decent piece of fish or a handful of chicken could not. They are a form of protein. If protein intake is low, which it often is in women over 40, there may be more of a case. Many clinicians would not discourage a client already using it where their diet is protein-limited.

Vitamin C: strong evidence, mostly topical

Vitamin C is one of the most studied ingredients in skincare. In its topical form the evidence is robust: it supports collagen synthesis in skin cells, has antioxidant properties, and can help with uneven tone. A well-formulated topical vitamin C is one of the few skincare ingredients worth recommending without too many qualifications.

The oral picture is different. Vitamin C is essential for collagen production throughout the body, and deficiency absolutely affects skin. But most adults in the UK are not deficient. If you eat fruit and vegetables regularly, you are likely meeting your requirements, and taking extra oral vitamin C on top of adequate intake does not appear to produce proportional additional benefits for skin. Where oral vitamin C does have a clear role is as a cofactor alongside iron supplements, because it increases how well the gut absorbs non-haem iron. That is a pharmacological effect with solid evidence, but the benefit is haematological, not cosmetic. The marketing often conflates "vitamin C is essential for skin" with "therefore extra vitamin C improves your skin." The first is true; the second does not follow if you are already replete.

For vitamin C, topical is where the skin evidence is. These are well-formulated options:

Exuviance Vitamin C Serum Capsules

£61

AllSkin Med C Radiance Gel

£65

SkinBetter Alto Defense Serum

£164

Biotin: the one most worth scepticism

Biotin (vitamin B7) is probably the supplement most commonly marketed for skin, hair, and nails. The bottles are everywhere; the claims are effusive; the evidence, for people without a deficiency, is sparse. Biotin deficiency is real and does affect skin and hair, with symptoms like dermatitis, hair thinning, and brittle nails, and supplementing genuinely deficient people resolves these. That is not in question. The problem is that frank biotin deficiency is uncommon in adults eating a varied diet, because biotin is found in eggs, nuts, seeds, meat, and many common foods. Most people taking biotin are not deficient, and for them, more biotin does not appear to produce meaningful additional benefits for skin or hair based on current evidence. For someone with a varied diet, it is hard to make a case for spending money on it.

Zinc: reasonable evidence, especially for inflammatory skin

Zinc has a more interesting evidence base than biotin. It is involved in wound healing, skin cell turnover, and has some anti-inflammatory properties. The research is most compelling for inflammatory skin conditions, particularly acne. Several studies have found zinc supplementation useful for inflammatory and cystic acne, including a Cochrane review that found some evidence for zinc sulphate, though not as strong as topical antibiotics. For general skin health in people without a deficiency, the evidence is less clear-cut. But for women with inflammatory or acne-prone skin, or where the diet may be low in zinc-rich foods like red meat, shellfish, or legumes, there is a reasonable case for considering it.

Omega-3 fatty acids: genuine evidence for barrier and inflammation

This is the category with the most convincing skin evidence. EPA (eicosapentaenoic acid, an omega-3 found in oily fish) and DHA (docosahexaenoic acid, another omega-3) both have well-established anti-inflammatory effects. Chronic low-grade inflammation contributes to conditions like eczema, psoriasis, and inflammatory acne, and plays a role in skin ageing, where sustained inflammation can interfere with collagen structure over time. Research on omega-3 supplementation shows improvements in skin hydration, a reduction in transepidermal water loss (TEWL, the rate at which skin loses water to the environment), and reduced inflammatory skin symptoms in conditions like atopic eczema. The evidence is not definitive enough to call omega-3 a skin treatment, but it is strong enough that if you are not eating oily fish twice a week and your skin is reactive, dry, or inflammatory, your omega-3 intake is worth looking at. Where the same supplement supports cardiovascular and hormonal health as well as skin, that is efficient.

How to decide whether a supplement is worth it for you

• Is there a plausible reason it could work? If no clear reason has been established, start with scepticism regardless of the marketing.
• What does the actual research show? "Research suggests" and "clinically tested" are almost always weaker than they sound. Look for randomised controlled trials, systematic reviews, or Cochrane analyses, and note who funded the studies.
• Are you deficient or genuinely low? Many supplements work mainly in the context of deficiency. If your levels are fine, more may not add proportionally more benefit.
• Is food a more practical option? Protein from food, zinc from seeds and meat, omega-3 from oily fish, vitamin C from fruit and vegetables. Supplements are not inherently superior to food.
• What else is going on? Sleep deprivation, chronic stress, and gut disruption affect skin in ways no supplement compensates for.

Related reading: Gut health is one of the biggest hidden influences on reactive skin. Read The Gut-Skin Axis: How Your Microbiome Impacts Eczema and Rosacea.

The short version of the updated position: some supplements have genuine evidence worth knowing about, most marketing still overstates that evidence considerably, a few categories have earned a place in the conversation, and biotin has absolutely not earned the number of Instagram posts it gets.

Shop the products in this post

Topical vitamin C, antioxidant support, and a healthy barrier are where the strongest skin evidence sits. These reflect that approach, alongside the full nutrition and gut picture in the guide:

Exuviance Vitamin C Serum Capsules

£61

AllSkin Med C Radiance Gel

£65

SkinBetter Alto Defense Serum

£164

AllSkin Med Barrier Recovery Cream

£84

AllSkin Med Mattifying Gel Cream

£65

AllSkin Med Purifying Cleansing Gel

£30

Beyond Prescriptions: The Anti-Inflammatory Guide for Women

£199.90

Browse the full range at deboratentis.com. For a plan that looks at skin, nutrition, and supplements together, book a Happy Skin Holistic Consultation at Debora Tentis Clinic (£60).

Keep reading: Topical retinoids have far stronger skin evidence than most oral supplements. Read Oestrogen and Skin: The Clinical Connection for how hormones shape skin quality.

Debora Tentis is a Women's Health Pharmacist and Independent Prescriber Trainee at Debora Tentis Clinic, Milton Keynes. This post is for educational purposes only and does not constitute medical advice.