If you have stood in front of a wall of bottles — in a Dutch drogist, in a Turkish eczane, or in a browser with forty tabs open — and wondered which supplements should I take, you are asking a reasonable question that the industry has made almost impossible to answer. You have probably been told to take magnesium for sleep, collagen for your skin, ashwagandha for stress, a greens powder because your vegetables are apparently not enough, and a multivitamin as insurance on top. Each one arrives with a discount code and the quiet implication that if you are tired or anxious, it is because you are missing something you could buy.
I want to take the blame out of this first. You are not gullible for having bought things that did nothing, and you are not neglecting your health if your bathroom shelf is empty. This is a market built to make everyone feel slightly deficient, and the confusion you feel is the intended product, not evidence that you read the labels badly. Here is the honest picture: a few supplements genuinely help specific people in specific situations, a slightly larger group is reasonable in narrow circumstances, and a very large category is advertising with a capsule around it. One safety note first — if you are pregnant or breastfeeding, have kidney or liver disease, or are in cancer treatment, please start nothing at all, herbal products included, without clearance from your doctor.
For deeper context, see: 5 Nutrition Changes That Actually Help with PCOS (From a Dietitian Who Gets It).
How I Think About the Question Before Anyone Names a Product
"Which supplement should I take?" cannot be answered in the abstract, and most of the bad advice in this field comes from people happy to answer it anyway. I do not start with products. I start with a gap.
Here is the principle I keep returning to: name the gap before you buy the fix. A supplement patches a specific hole — a nutrient your diet cannot supply, a condition that raises your requirement, a medication that blocks absorption, or a life stage with an extra need. If nobody can tell you which hole a product patches, there is nothing to evaluate.
So three questions come first. Is there a plausible reason to think you are low, given your diet, history, medications and symptoms? Would food cover it more reliably and more cheaply? And is it safe alongside your medications? Most of what people arrive taking does not survive the first question.
The Short List That Earns Its Place, and Who It Is For
There genuinely is a short list, and every item comes with a "for whom" attached.
- Vitamin D. The strongest case here for anyone in the Netherlands, Belgium, Germany or northern Turkey, where the sun is too weak for skin synthesis much of the year — stronger again if you have darker skin, cover your skin, work indoors, or are pregnant.
[TK: confirm range]More in nutrition for vitamin D deficiency. - Vitamin B12. Essential on a vegan diet, and worth discussing if you are vegetarian, older, take metformin or long-term acid-suppressing medication, or have had bowel surgery. Untreated deficiency can cause nerve damage that does not fully reverse.
[TK: confirm range]See B12 deficiency and what to eat. - Folic acid before and in early pregnancy. One of the very few supplements with a clear, universally agreed case, and it must begin before conception.
[TK: confirm range] - Omega-3 fats. Worth considering if you eat little or no oily fish, with algae-derived options for plant-based diets.
[TK: confirm range]See omega-3 and healthy fats. - Iron, but only with a confirmed deficiency. Iron you do not need causes constipation at best, and real harm in people with certain genetic conditions. A blood test and a doctor, every time.
- Magnesium, in narrower circumstances than the internet suggests. Most people meet their needs from food, and I say that as someone asked about magnesium constantly.
[TK: confirm range]See the food sources of magnesium.
Notice how narrow that list is, and how every entry turns on something true about you — your diet, your medication, your latitude, your life stage. A list of best vitamins to take written for everybody is meaningless.
The Multivitamin Question, and Why Testing Beats Guessing
The multivitamin is the most sympathetic purchase here, because the logic is decent: you cannot be certain your diet is perfect, so you take a little of everything as insurance.
The trouble is what "a little of everything" means. A standard multivitamin gives modest amounts of many nutrients — usually too little of the one thing you might genuinely be low in, and unnecessary for the twenty you are not. Let me be direct about a point the wellness world stays quiet about: some nutrients are harmful in excess. The fat-soluble vitamins accumulate rather than washing out, excess vitamin A is a specific concern in pregnancy, long-term high intakes of certain B vitamins have been linked with nerve symptoms, and selenium has a narrow window between useful and toxic. [TK: confirm range] That does not make a multivitamin dangerous for most people. It does make "just in case" a weaker argument than it sounds.
The alternative is unglamorous and works far better: test, treat, retest. Ask your doctor for the relevant blood test, treat what the result shows with a dose chosen for you, and check again after an appropriate interval so you know whether it worked and when to stop. [TK: confirm range] One honest caveat: not everything is usefully testable, and for some nutrients a careful conversation about your diet tells us more than a blood level does. A normal result is information too — it means you can stop buying that product.
"Natural", "Food-Based", and the Category That Is Marketing
Almost none of the words that reassure you on a supplement label are regulated terms with fixed meanings. "Natural" is the emptiest. It describes an origin story, not a safety profile, and says nothing about dose, purity, or whether the compound interacts with your medication. "Food-based" usually means a little concentrate added to an otherwise conventional base so the phrase can appear on the front. "Clean", "pure" and "doctor-formulated" have no defined standard behind them at all.
Regulation explains a great deal. In the European Union, supplements sit under food law rather than medicines law, so a product does not have to demonstrate that it works before it is sold. Enforcement of the health claim rules lags far behind the internet, and anything bought from a non-EU webshop is outside the system entirely. Turkey has a different framework again. That gap is where the marketing category lives: detox teas, slimming products, greens powders sold as a vegetable substitute, collagen, fat burners, and most things advertised with a before-and-after photograph.
Quality, Contamination, and Interactions With Your Medication
Two risks are badly underestimated, and they are the two I care most about clinically.
The first is what is in the bottle. Because efficacy is not assessed before sale, quality control varies enormously between manufacturers. Under-dosing against the label is common, and heavy metal contamination has been found in some plant-derived and imported products. More seriously, undeclared pharmaceutical ingredients turn up repeatedly in weight-loss and bodybuilding products, so a person can end up taking a real drug at an unknown dose. Independent third-party testing is the best protection a consumer has; Informed Sport and NSF Certified for Sport are the schemes most often seen, and their presence is a reasonable proxy for quality control.
The second risk is interaction. Supplements are pharmacologically active — that is the entire reason people take them — and they can interfere with the medications keeping you well. Anticoagulants are the clearest example, where vitamin K intake, high intakes of omega-3 and several herbal products all matter. Thyroid medication is affected by the timing of calcium, iron and magnesium. Some antidepressants interact dangerously with serotonergic herbal products. Antioxidant and herbal supplements should never be added independently during chemotherapy or immunotherapy, because they can change how the treatment behaves. So your doctor and your pharmacist must know about everything you take — the vitamins, the capsules, the teas, the powder in your smoothie. Bring the packages.
Herbal Supplements, and Why I Am Careful Here
I trained in phytotherapy, and people expect that to make me enthusiastic about herbal products. It has had the opposite effect, for a specific reason: herbal medicine is real pharmacology, and that is exactly why it deserves care rather than romance.
A plant is not a single substance. It is a variable mixture whose composition shifts with species, growing conditions, plant part and, above all, extraction method. A cup of herbal tea and a concentrated standardised extract of the same plant are not equivalent, and a product with no stated plant part or standardisation is essentially unknowable.
The interaction issue is sharpest here. St John's wort is my constant case study: it has a genuine evidence base in mild to moderate depression, and it is also a potent inducer of the liver enzymes that clear many medications, so it can reduce the effectiveness of oral contraceptives, anticoagulants, some antidepressants and several cancer treatments. Liver injury is the other concern worth naming, reported with concentrated green tea extracts and some slimming preparations, though not with ordinary tea.
Buying mixed herbs from an aktar is a long tradition and often a warm, knowledgeable experience, but unlabelled loose mixtures cannot be checked for interactions, and I have seen people take them alongside blood pressure and thyroid medication without telling anyone. If you use herbal preparations, tell your doctor.
What a Food-First Version Looks Like on Your Plate
It is worth seeing what the food version of each commonly supplemented nutrient looks like. This is illustrative, and portions should be personalised.
- Omega-3 fats: oily fish such as salmon, mackerel, sardines or anchovies a couple of times a week, plus walnuts, flaxseed and rapeseed oil.
- Magnesium: wholegrains, legumes, nuts and seeds, dark green leafy vegetables and dark chocolate.
- Iron: red meat and liver for the haem form, and lentils, beans, dark leafy greens, dried apricots and tahini for the plant form, eaten with a source of vitamin C.
- Calcium and folate: dairy and fermented dairy, tinned fish with soft bones, tahini, almonds, pulses, citrus and green leafy vegetables — with the exception that planning a pregnancy needs a folic acid supplement as well as the food.
- Protein, instead of the powders: eggs, dairy, fish, poultry, meat, lentils, chickpeas, tofu and yoghurt spread across the day.
- Vitamin B12 and vitamin D: the two honest exceptions. Fortified foods carry B12, but a vegan diet needs a supplement however well it is planned, and vitamin D is the one nutrient food cannot carry through a northern winter.
Notice that the same handful of foods keeps reappearing — fish, pulses, nuts and seeds, dairy, leafy greens, wholegrains. That repetition is the point, and it is why my first hour with a client goes on the week's meals.
Common Supplement Myths
"If it is natural, it cannot hurt me."
Natural describes where a substance came from and says nothing about potency or safety. Several of the most significant medication interactions in clinical practice involve plant products, and some nutrients cause real harm in excess whatever their origin.
"A multivitamin covers me, just in case."
A multivitamin provides small amounts of many nutrients, which is often not enough of the one thing you are actually low in and unnecessary for everything else. Where there is real reason to suspect a deficiency, a targeted test serves you far better.
"My supplements are not medication, so my doctor does not need to know."
Your doctor and pharmacist need the complete list, including herbal capsules and teas. Interactions with anticoagulants, thyroid medication, some antidepressants and cancer treatments are well documented, and nobody can check for something they do not know about.
"Supplements are tested and approved like medicines."
In the European Union they are regulated as food, so a product does not have to prove that it works before going on sale, and the rules differ again in Turkey. This is why independent third-party testing is worth looking for on a label.
Working With Hanzi Nutrition
I am a dietitian and a phytotherapy specialist, and my honest position is that most people arrive taking too many supplements and too few of the right ones — and that almost everyone is better served by a decent week of meals and one or two well-chosen products than by a shelf bought one panic at a time.
At Hanzi Nutrition, I work fully online with clients across the Netherlands, Belgium, Germany, and Turkey, in both English and Turkish. We begin with a first consultation covering your eating pattern, medical history, medications, blood results if you have them, and everything you currently take, down to the teas. From there I build a personalised plan that gets food doing as much of the work as it can, fits your kitchen, your culture, your budget and your schedule, and tells you which supplements have a place for you, which are worth testing for first, and which you can stop buying today. Where any of it touches your medication, I coordinate with, and never replace, your doctor and pharmacist.
If you are tired of guessing and want an honest answer about which supplements are worth your money and which you can stop taking, book a consultation with me today.
Hanzi Nutrition offers dietitian-led nutrition counselling across the Netherlands, Belgium, Germany, and Turkey, fully online, in English and Turkish. This article is general education and not a substitute for individual medical care. Supplements interact with prescribed medication and some nutrients are harmful in excess, so please discuss anything you take with your doctor and pharmacist — and start nothing without medical clearance if you are pregnant or breastfeeding, have kidney or liver disease, or are in cancer treatment.
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