What Supplements Should I Take Quiz

Not sure which supplements you actually need? Take our free 2-minute what supplements should I take quiz below. Answer 10 quick questions about your diet, sun exposure, energy, digestion, health goals and life stage, then match your answers to a personalised shortlist. For most adults in the UK, the honest answer is short: the NHS advises a daily vitamin D supplement (10 micrograms) from October to March, plus folic acid if you could become pregnant. Everything beyond that depends on your diet, blood results and goals — which is exactly what this quiz helps you work out.

Key takeaways

• Almost everyone in the UK should consider 10 µg (400 IU) of vitamin D daily in autumn and winter, according to NHS advice.
• Most other supplements are situational — they help when there is a genuine shortfall (diet, life stage, medication, absorption problem), not automatically.
• A blood test beats guesswork for vitamin D, ferritin (iron) and B12 — you avoid paying for nutrients you already have enough of.
• More is not better. Several nutrients (iron, vitamin A, B6, zinc, selenium) have safe upper limits that are easy to exceed by stacking products.
• Supplements are regulated as food in the UK, not as medicines — so they are not assessed for effectiveness before sale. Quality and dose vary.
• Always check interactions if you take prescription medication, are pregnant or breastfeeding, or have kidney, liver or thyroid conditions.

What supplements should I take? (Short answer)

Most healthy UK adults need only one supplement year-round: vitamin D 10 µg daily from October to March. Add folic acid 400 µg if you might become pregnant, vitamin B12 and iodine if you eat a vegan diet, and iron or B12 only if a blood test confirms a deficiency. Everything else should be matched to a specific goal, symptom or dietary gap.

Before you take the quiz: three questions worth asking first

A supplement is worth taking when it closes a real gap. Before spending money, work through these three checks — they eliminate most unnecessary purchases.

1. Is there a plausible shortfall? Think about what your diet consistently lacks — oily fish, dairy, red meat, fruit and vegetables, or whole food groups you avoid.
2. Can it be measured? Vitamin D, ferritin, B12 and folate can all be tested. If a nutrient can be measured, testing is more reliable than guessing.
3. Is something else the real cause? Persistent fatigue, low mood or poor sleep are more often caused by sleep debt, thyroid problems, anaemia, stress or a medical condition than by a vitamin deficiency. Supplements will not fix those.

If you are not sure where you stand, a nutrition and vitamin blood test measures vitamin D, B12, iron status and key minerals in one go, so your choices are based on your numbers rather than assumptions.

What Supplements Should I Take Quiz

Instructions: Answer each of the 10 questions below with the option that best describes you. Write down your letters as you go (for example: A, B, B, C, A…). At the end, count how many As, Bs and Cs you scored and read the matching result. This quiz gives general educational suggestions only — it is not a diagnosis, and it does not replace advice from your GP, pharmacist or dietitian.

1. Dietary habits

• A. I eat a balanced diet with plenty of fruits, vegetables, and whole grains.
• B. I occasionally miss out on some food groups like fruits or vegetables.
• C. My diet is limited and often lacks variety.

2. Sun exposure

• A. I get plenty of sun exposure daily (and mostly in spring and summer).
• B. I get moderate sun exposure.
• C. I rarely get sun exposure, work indoors, cover my skin, or have deeper skin tone.

3. Health goals

• A. Boost overall health and wellness.
• B. Support bone and joint health.
• C. Enhance athletic performance or muscle building.
• D. Support heart health or circulation.

4. Digestive health

• A. I have no digestive issues.
• B. I occasionally experience digestive issues like bloating or discomfort.
• C. I frequently suffer from digestive problems.

5. Energy levels

• A. I usually feel energetic throughout the day.
• B. I often feel tired or have energy slumps.
• C. I constantly feel fatigued or lethargic.

6. Allergies and dietary restrictions

• A. I have no known allergies or dietary restrictions.
• B. I am lactose intolerant or have other specific food allergies.
• C. I am vegan or vegetarian.

7. Age and life stage

• A. Below 30 years.
• B. Between 30 and 50 years.
• C. Above 50 years.

8. Stress and mental health

• A. I rarely experience stress or anxiety.
• B. I sometimes feel stressed or anxious.
• C. I frequently experience high levels of stress or anxiety.

9. Exercise and training load

• A. I move regularly but do not train intensively.
• B. I train 3–5 times a week, including some resistance work.
• C. I train intensively, compete, or have heavy sweat losses most days.

10. Medication, pregnancy and medical conditions

• A. No regular medication, no pregnancy plans, no diagnosed conditions.
• B. I take one or more regular medicines (for example, anticoagulants, levothyroxine, metformin, antidepressants or a proton pump inhibitor).
• C. I am pregnant, breastfeeding, or trying to conceive.

Important: if you answered B or C to question 10, speak to your GP or pharmacist before starting anything new. Several common medicines interact with supplements — see supplement and medication interactions below.

Your quiz results

• Mostly As — you already have solid foundations. Your diet, energy and digestion are working well. A daily vitamin D supplement in autumn and winter is likely all you need. A basic multivitamin is optional insurance rather than a necessity.
• Mostly Bs — you have one or two identifiable gaps. You may benefit from vitamin D year-round, omega-3 (EPA and DHA) if you rarely eat oily fish, magnesium if sleep and muscle cramps are an issue, and a probiotic trial if bloating is frequent.
• Mostly Cs — test before you supplement. Frequent fatigue, ongoing digestive problems and a restricted diet together suggest something measurable is going on. Ask your GP about a blood count, ferritin, B12, folate, vitamin D and thyroid function, or start with a comprehensive at-home blood test. Supplement to your results, not to your symptoms.
• Mixed answers? Use the goal-based table below instead of the letter score — most people fall between categories.

Which supplements does the NHS actually recommend?

This is the part most supplement quizzes skip. In the UK, only a handful of supplements are recommended at population level. Everything else is optional and situational.

You can read the full guidance on the NHS vitamins and minerals and vitamin D pages.

UK daily amounts and safe upper limits (dosage chart)

Reference nutrient intakes (RNIs) are the amounts that meet the needs of most people. The "safe upper level" column reflects NHS advice on daily supplement amounts that are unlikely to cause harm. Stacking a multivitamin with several single-nutrient products is the most common way people quietly exceed these.

Key fact: vitamin D is measured in both micrograms and international units. 10 µg = 400 IU, and 25 µg = 1,000 IU. If the maths confuses you, our guide to what 1,000 IU means on a vitamin D test explains the conversion.

What supplements should I take for my specific goal?

Use this table if your quiz answers were mixed, or if you have one clear objective rather than a general wish to "feel better".

Browse by category if you already know what you are looking for: all vitamins and supplements, bone, joint and muscle supplements, supplements for tiredness and fatigue, women's health supplements and men's health supplements.

What does the evidence actually show?

Supplement marketing rarely distinguishes between "proven", "promising" and "unproven". This summary does. Where evidence is limited, we say so.

You can check primary research yourself on PubMed and read systematic reviews at the Cochrane Library.

Should you take a blood test before supplementing?

Testing is worth it when the result would change what you do. Use this decision tree.

• Symptom-free and eating well? → Take vitamin D in winter. No test needed.
• Tired for more than a few weeks? → Test full blood count, ferritin, B12, folate, vitamin D and thyroid before buying anything.
• Vegan for over a year, or on long-term metformin or a PPI? → Test B12.
• Heavy periods, blood donation, or plant-based diet? → Test ferritin before taking iron.
• Already taking supplements and unsure if they work? → Test, then stop what is not needed.

At-home options include the Welzo vitamin D blood test (lab-analysed 25-hydroxyvitamin D), the instant vitamin D test for a result in around 10 minutes, and the broader women's health blood tests range. Always take unexpected or abnormal results to a clinician for interpretation.

When should you take each supplement?

Timing matters less than consistency, but a few rules genuinely change absorption.

For a fuller breakdown, see our supplement timing chart.

Supplement and medication interactions to check

This is the single most important safety section on this page. If you take regular medication, check before you start.

Pregnancy: avoid supplements containing retinol (vitamin A) and avoid liver. Take folic acid 400 µg daily until 12 weeks, and vitamin D 10 µg throughout. Some people need a higher 5 mg folic acid dose — for example if you have diabetes, a raised BMI, epilepsy treated with certain medicines, or a previous pregnancy affected by a neural tube defect. Your midwife or GP will advise.

Common mistakes people make with supplements

• Buying for symptoms instead of causes. Fatigue has dozens of causes; a vitamin is rarely the main one.
• Stacking overlapping products. A multivitamin plus a B-complex plus a "greens" powder can push zinc, B6 or vitamin A past safe limits.
• Stopping after a week. Correcting a deficiency in iron, B12 or vitamin D usually takes 8–12 weeks or more.
• Assuming "natural" means risk-free. Herbal products such as St John's wort have real, clinically significant interactions.
• Ignoring the form. Vitamin D3 raises blood levels more effectively than D2; magnesium oxide is poorly absorbed compared with citrate or glycinate.
• Skipping the label check. UK supplements are regulated as food, so the dose and quality vary between brands — look for third-party testing.
• Treating supplements as an alternative to seeing a GP. Unexplained weight loss, breathlessness, blood loss or persistent symptoms need medical assessment.

Myth vs fact

How to choose a quality supplement: a 6-point checklist

1. Check the active dose, not the headline claim — compare against the RNI table above.
2. Check the form — vitamin D3 (cholecalciferol), methylcobalamin or cyanocobalamin B12, magnesium citrate or glycinate, ferrous fumarate or bisglycinate iron.
3. Look for third-party or batch testing and a clear manufacturing standard.
4. Avoid proprietary blends that hide individual ingredient amounts.
5. Match the format to your life — capsules, sprays, gummies and liquids all work if you actually take them. Gummies often contain lower doses and added sugar.
6. Check suitability — vegan, halal, gluten-free, allergen and lactose information.

If you want a shortlist rather than the full range, see our editorial guides to the best vitamin brands and best vitamin D3 supplements ranked, or the Welzo editors' pick of supplements.

Building your routine: a 4-week step-by-step plan

1. Week 1 — establish the baseline. Start vitamin D 10 µg daily. Note your energy, sleep and digestion in a simple log.
2. Week 2 — test if indicated. If fatigue, restricted diet or long-term medication apply to you, arrange bloods before adding anything else.
3. Week 3 — add one targeted supplement. One at a time only, so you can tell what is working. Give it at least 8 weeks.
4. Week 4 — review and prune. Cancel anything with no plausible rationale, no measurable target and no noticeable effect. Re-test deficiencies at 3 months.

Frequently asked questions

How do I know which supplements I need?

Match supplements to gaps rather than symptoms. Start with the NHS baseline (vitamin D in winter, folic acid if you could become pregnant, B12 and iodine if vegan), then use blood tests for anything measurable such as ferritin, B12 and vitamin D. Take the quiz above for a personalised shortlist.

Is it OK to take a multivitamin every day?

For most healthy adults, yes — a standard multivitamin providing around 100% of the RNI is generally safe daily. It becomes risky when combined with several single-nutrient products, which can push vitamin A, B6, zinc or iron past safe limits.

What supplements should I take daily for the best value?

Vitamin D is the clearest value for money in the UK. After that, spend on what you can justify: omega-3 if you rarely eat oily fish, B12 and iodine if you are vegan, and creatine if you strength train. Most other purchases are optional.

Can I take too many vitamins?

Yes. Fat-soluble vitamins (A, D, E, K) accumulate in the body, and minerals such as iron, zinc and selenium have narrow safe ranges. Symptoms of excess include nausea, headaches, hair loss and, in the case of vitamin D, dangerously high blood calcium.

Which supplements should I avoid taking together?

Keep calcium and iron at least two hours apart, keep zinc and copper in balance, and separate minerals from levothyroxine and certain antibiotics by several hours. Avoid combining several products that each contain the same nutrients.

How long do supplements take to work?

It depends on what you are correcting. Vitamin D levels typically take 8–12 weeks to rise meaningfully; iron stores can take three to six months to rebuild; B12 improvements may be felt within weeks. If nothing has changed after three months, re-test rather than adding more.

Do I need supplements if I eat a healthy diet?

Usually far fewer than the marketing suggests — but vitamin D is the exception, because it depends on sunlight rather than diet. Vegans also need B12 and iodine regardless of how well they eat.

Are supplements regulated in the UK?

Supplements are regulated as food, not as medicines. That means they must be safe and accurately labelled, but they are not assessed for effectiveness before sale in the way licensed medicines are. Products making medicinal claims fall under MHRA regulation instead.

Should I take supplements while pregnant?

Take folic acid 400 µg daily until 12 weeks and vitamin D 10 µg throughout pregnancy. Avoid supplements containing retinol (vitamin A) and avoid liver. Check any other product with your midwife, GP or pharmacist.

Is this quiz a substitute for medical advice?

No. It is an educational starting point for a conversation with a healthcare professional. If you have a diagnosed condition, take regular medication, are pregnant or breastfeeding, or have persistent symptoms, get personalised advice before starting anything new.

Conclusion: use the quiz as a starting point, not a shopping list

The most useful outcome of this quiz is often a shorter supplement list, not a longer one. For most people in the UK, the evidence supports a small, boring core — vitamin D through the darker months, folic acid before and during early pregnancy, B12 and iodine on a vegan diet — plus a small number of targeted additions justified by a blood test or a specific goal.

Your needs will change with your age, diet, training, medication and health, so revisit your answers every six to twelve months. And treat any supplement decision that involves prescription medicine, pregnancy or an ongoing symptom as a conversation for your GP or pharmacist rather than a decision to make alone.

When you are ready to act on your results, explore vitamins and supplements at Welzo, compare options in the multivitamins collection, or start with a nutrition and vitamin blood test so your choices are guided by data.

Disclaimer: This quiz and article are for general information only and are not a substitute for professional medical advice, diagnosis or treatment. Always consult a qualified healthcare professional before starting, stopping or changing any supplement, particularly if you are pregnant, breastfeeding, taking prescription medication or managing a health condition.