Walk into any community pharmacy and the supplement aisle is the widest and fastest-changing category on the shop floor. New products arrive every month. Old ones are repackaged. Claims get bigger. The one thing that does not move much is the underlying evidence — which is why PharmSee has built a systematic, pharmacist-led series of supplement guides rooted in clinical-knowledge summaries, the BNF, and published trial evidence.

This page is the hub. Use it to find the specific supplement you are researching, and follow the linked guide for the detail — product forms, dosing, interactions, and when a supplement is not worth taking at all.

The supplement-evidence series

Every linked article below is written to the same standard: start with the evidence, state what the product does and does not do, cover dosing and forms a pharmacist will actually stock, and flag interactions and red flags. No hype, no miracle framing.

Muscle, joints and movement

• Creatine supplements at the pharmacy — strong evidence for strength and lean mass; emerging evidence in ageing and cognition. Monohydrate remains first-line.
• Glucosamine and chondroitin for knee osteoarthritis — modest symptomatic effect at best; guideline position is lukewarm.
• Topical NSAID gels for musculoskeletal pain — not a supplement, but the counter alternative most patients end up asking about.
• Capsaicin cream for joint pain — second-line for osteoarthritis of the hand and knee; application-dependent.
• Collagen supplements — skin, joints and hair — evidence is thin for hair and skin, marginal for joint symptoms.
• Coenzyme Q10 — statins, migraine and heart failure — targeted populations only.

Nutrient status and metabolism

• Magnesium supplements — types and uses — different salts for different indications; tolerability matters.
• Vitamin B12 — cyanocobalamin vs methylcobalamin — diet, absorption and IM requirements.
• Zinc — colds, wound healing and taste — short-course cold effects are marginal; longer use carries interaction risk.
• Omega-3 — REDUCE-IT, STRENGTH and VITAL in context — cardiovascular outcomes are indication-specific; icosapent ethyl is not a retail product.
• Vitamin D — UK adult guidance — 10 micrograms daily from October to March for most adults; higher doses need review.
• Iron supplements matched to the indication — pregnancy, HMB, coeliac and vegetarian needs diverge.
• Iron for heavy menstrual bleeding — the leading working-age iron-deficiency cause.
• Iron supplements in pregnancy — salts, formulations and tolerability.

Gut and microbiome

• Probiotics — evidence, IBS and antibiotic cover — strain-specific evidence; broad-spectrum claims rarely justified.
• Prebiotics vs probiotics — what's the difference — distinct mechanisms, different counter conversations.

Sleep, mood and performance

• Melatonin and 5-HTP for insomnia — prescription-only in the UK for melatonin; 5-HTP is retail.
• Valerian, lavender, chamomile for sleep and anxiety — traditional herbal medicines framework.
• Ashwagandha and other adaptogens — emerging evidence, widely claimed.
• Pre-workout supplements in 2026 — caffeine plus a stacked ingredient list; safety profile varies.

How to read the evidence

Three distinctions that keep re-emerging across the series.

Indication matters more than ingredient. Omega-3 in cardiovascular prevention is not the same product, dose or evidence base as omega-3 in dry eye. Iron in pregnancy is not the same question as iron in heavy menstrual bleeding. Make sure the claim matches the condition.

Study quality varies. Supplement evidence ranges from rigorous meta-analyses (creatine and strength, omega-3 in secondary cardiovascular prevention) to small open-label trials (many adaptogen claims). The series links to primary sources where they exist.

Interactions are the single most underweighted risk. Supplements are sold as if they sit outside the prescription register, but they interact. Zinc binds tetracyclines and quinolones. St John's Wort induces CYP3A4. Omega-3 adds to bleeding risk. Magnesium binds bisphosphonates. Every supplement consultation deserves a look at the full medicines list.

What this series is not

PharmSee does not publish endorsements of specific brand SKUs. Product examples are illustrative — a patient should choose a supplement that matches the form, dose and quality mark (traditional herbal medicines authorisation, food supplement manufactured to GMP) relevant to their indication.

Sector context

PharmSee's tracker recorded 1,651 live UK pharmacy vacancies across eleven public sources on 14 April 2026. The counter is busy; supplement consultations are a high-value use of limited counter time when approached with evidence rather than packaging.

Caveats

Every article in this series is written from the evidence at time of publication. Guidance changes. Always work from current NICE CKS, BNF and SmPC information when advising on specific products.

Sources

• NICE Clinical Knowledge Summaries.
• British National Formulary.
• Published trial evidence as cited in each linked series article.