Pills taken by millions can interact with dangerous results, experts say
Neil Shaw Network Content Editor
11:09, 13 Jul 2026Updated 11:10, 13 Jul 2026
Millions of people combine pills without knowing the risks
More people are combining multiple vitamins, minerals, and herbal products into daily “stacks”, but health experts have warned some people are putting themselves at risk of serious illness. Rhysa Phommachanh at Landys Chemist, said people taking some medications should avoid key supplements – or risk making their health worse.
Rhysa said: “The problem with supplement stacking is that these combinations are often copied from social media rather than based on blood tests, diet, medication use or individual health needs. The main risk is accidental overuse.
“Someone may take a multivitamin, an ‘immune’ powder and a separate vitamin D or zinc supplement without realising they are duplicating ingredients. Fat-soluble vitamins such as A and D can build up in the body, while too much iron, zinc or selenium can cause side effects and interfere with other nutrients.
Many people take supplements in a bid to boost health
“Interactions are another concern. For example, St John’s wort can affect medicines including hormonal contraceptives and antidepressants, vitamin K can interfere with warfarin, and minerals such as calcium, iron and zinc can compete for absorption if taken together.
“A safe supplement routine should be personalised. The best approach is to first identify a genuine need, check for overlap between products, and consider medicines and medical conditions.”
Rhysa explained key steps to take to reduce any risks when taking multiple supplements:
Beware of medication interactions: If you take prescription or over-the-counter medicines, check with a pharmacist or healthcare professional before starting a new supplement, as some ingredients can affect how medications work.Avoid assuming ‘natural’ means risk-free: Natural doesn’t always mean harmless. Herbal supplements and plant-based ingredients can still have side effects or interact with medications.Space out certain minerals where appropriate: If you’re taking supplements containing iron, calcium, magnesium, or zinc, it may be worth taking them at different times of the day, as some minerals can compete for absorption.Check ingredient labels carefully: Ensure you check the ingredient label thoroughly and compare products to spot duplicate vitamins and minerals before adding something new to your routine.Only supplement when there’s a genuine need: Always base your choices on advice from a healthcare professional, dietary requirements or confirmed deficiencies, rather than social media trends.Review your supplements regularly: Review your supplement routine every three to six months, or sooner if your diet, health, or medications change, to make sure you’re still taking only what you need.Stick to the recommended dose: Follow the dosage on the label or the advice of your healthcare professional, and avoid taking multiple products containing the same nutrient unless you’ve been advised to do so.