In short
- Decide what you want from a supplement before you buy one, and check whether food or a change in routine could meet it.
- Tell a pharmacist or clinician about everything you take, including herbs and vitamins.
- Check the label for allergens, other ingredients, warnings and the amount per serving.
- Change one thing at a time and note what you take.
Buying a supplement takes a minute; deciding whether it suits you deserves a few more. The questions below are the ones a thoughtful pharmacist or dietitian would ask. You can work through them on your own, and bring the ones that you cannot answer to a professional. None of them requires special knowledge, only a willingness to check.
Questions for yourself
1. What is my reason for taking this?
"It was on sale" and "a friend takes it" are common answers, but they are not reasons. Try to write one sentence: "I want to ... because ...". If you cannot, wait. If a clinician has recommended a specific product or amount, follow their advice and not a general article, including this one.
2. Could food or routine cover it?
Many nutrients can be obtained from a varied diet. A supplement can be sensible when diet is restricted, when needs are higher at a certain stage of life, or when a clinician has identified a gap, but it is an addition to food, not a replacement for it.
3. What am I already taking?
List everything: multivitamin, single nutrients, herbs, protein powders, fortified foods and drinks. Many products contain the same nutrients, and totals can climb without anyone noticing. See the double-up problem.
4. How will I know if it is working, or not agreeing with me?
Decide in advance what you will watch for and for how long. Start one new product at a time. If you begin three at once, a reaction cannot be traced to its cause.
Questions for your pharmacist or clinician
5. Does it interact with my medicines?
This is the single most important question. Some herbs and nutrients change how medicines are absorbed or broken down. A pharmacist can check the list quickly. Bring the product or a photo of the label so they can see the exact ingredients and amounts.
6. Is it suitable for me right now?
Pregnancy, breastfeeding, an upcoming procedure, kidney or liver conditions, and age all change the answer. Many clinicians ask patients to disclose all supplements before surgery.
7. What amount and when?
Some nutrients are better absorbed with food; some are better apart from others. A pharmacist can suggest a sensible schedule around your medicines and meals.
Questions for the label
8. What exactly is in it, and how much?
Check the serving size, the amount per serving, the form of each ingredient and the % Daily Value. Our guide to reading a label shows how, and ingredient forms explains the words in brackets.
9. What else is in it?
The "other ingredients" line lists capsule material, fillers, sweeteners, flavors and allergens. If you avoid animal products, gluten, soy, dairy, sugar or artificial colors, this is where to look.
10. What do the warnings say?
Warnings are not boilerplate. They tell you who should check first, what to avoid combining and where to store the product. Iron-containing products and sleep products, for example, carry specific cautions.
11. Is it within the upper limits?
If you are combining products, add up the totals for nutrients with published upper limits, particularly vitamins A and D, iron, zinc, calcium, niacin and vitamin B6. A table is in Vitamins and minerals: what is the difference?
12. Can I tell who made it and how to reach them?
A label should show the name and place of business of the manufacturer, packer or distributor. A reputable brand makes it easy to contact them with questions.
Questions for the seller
13. What is the return policy?
Know before you buy. See our shipping and returns page and our FAQ.
14. Where does the product ship from, and how has it been stored?
Heat and humidity can degrade some products. Ask the seller how products are stored and shipped, and check the expiry date when your order arrives.
A short routine
- Write down why you want the product.
- List what you already take.
- Show the label to a pharmacist.
- Start one new product, at the labeled amount, at a time you can remember.
- Note what you take and when (a log template is here).
- Review after a few weeks, and again at your next check-up.
It is a small amount of effort, and it keeps the decision where it belongs: with you and the professionals who know your situation.