You need to tell your physician the name and the dose of every vitamin, mineral, herbal product and mixture you use, and how long you have been using it. Because these products are not obtained on prescription in the way medicines are, they are often not counted as a “medicine” and go unmentioned at the consultation. Yet they may interact with the medicines you take and may affect laboratory results.
This is the item most often overlooked at a consultation. It is common for a patient who answers “no” to the question “Do you use any medicines?” to be taking three separate supplements a day. Because the question is heard as covering only medicines, supplements are not mentioned.
The most practical approach is to bring the boxes with you. Because the name, the contents and the dose are written on the box, this is more reliable than trying to remember them.
What should you tell your physician?
- The full name of the product (not “vitamin pill”, but the name on the box)
- Its contents (the ingredient list on the back of the box)
- The dose, and how many times a day you use it
- How long you have been using it
- Why you started using it (on a physician’s advice, on your own initiative, or on the recommendation of an acquaintance)
- Herbal teas and mixtures, if you drink them regularly
- Products brought in from abroad or bought over the internet (these matter particularly, because their contents may be uncertain)
- Any changes you have noticed after using them (stomach complaints, a rash on the skin, a change in sleep)
Why is this important?
They may interact with medicines. Some herbal products and high-dose supplements may alter the effect of the medicines being taken. Blood thinners and medicines for blood pressure, thyroid and diabetes are asked about separately for this reason.
They may affect laboratory results. Some supplements may alter blood test results. If your physician does not know which supplement you are using, they may interpret the result as something other than what it is.
Their contents are not always limited to what is on the label. Particularly in mixtures whose contents are uncertain, substances not listed on the label may be present.
Unnecessary use provides no benefit. Taking a supplement when no deficiency has been demonstrated does not provide the expected contribution. Starting one without an assessment may also delay recognition of the underlying cause.
What does the legislation say?
The Turkish Medicines and Medical Devices Agency (opens in a new tab) states that promoting and selling a product with claims implying that it benefits human health or is effective against diseases is contrary to the legislation, and it applies administrative sanctions in this area.
In other words, a promotional claim that a product is effective against diseases does not mean the product does this; on the contrary, such a claim is itself contrary to the legislation.
The World Health Organization (opens in a new tab) likewise emphasises an evidence-based approach for traditional and herbal products; it states that, even where they have been in use for a long time, it is critical that efficacy and safety be established through rigorous scientific validation.
In which patients is additional care needed?
In the following situations, supplement use is assessed separately:
- In patients who are pregnant or breastfeeding (some products are not suitable)
- In patients taking blood thinners (the risk of interaction is asked about separately)
- In patients with kidney or liver failure (accumulation may occur because excretion is altered)
- In patients receiving active oncological treatment (follow-up lies with the relevant specialty; the addition of any product is discussed with that team)
- In patients for whom surgery is planned (some products may need to be stopped before the procedure)
- In patients over 65 who use more than one medicine (the likelihood of interaction is considered together)
- In patients under 18 years of age (assessment lies within the field of paediatrics; this content has been prepared for adults)
Points to be aware of
The word “natural” does not mean safe. That a product is herbal does not mean it cannot interact or cause side effects.
A high dose does not mean better. Some vitamins may accumulate in the body and, at high doses, may lead to unwanted effects.
Before deciding on your own to stop a product you are using, consult your physician too. Some products may have been started on a physician’s advice.
That a product has helped someone else does not mean it is suitable for you. Suitability is assessed together with your current medication and your existing conditions.
Results vary from person to person.
When should you see a physician without delay?
If you notice these symptoms, consult a physician without delay:
- A rash, itching or swelling appearing on the skin after starting a supplement
- The onset of nausea, vomiting, abdominal pain or diarrhoea
- Marked darkening of the urine
- Yellowing of the whites of the eyes or of the skin
- A change you have noticed in the effect of a medicine you are taking
In the event of shortness of breath, swelling of the face or tongue, or difficulty swallowing, go directly to the emergency department.
Frequently asked questions
Is it essential to mention my supplements at the consultation?
Yes. Because supplements are not obtained on prescription, they may not be counted as medicines, but they may interact with your current medication and may affect laboratory results. The most practical approach is to bring the boxes with you; the name, the contents and the dose are written on the box.
Should herbal tea be mentioned as well?
If it is drunk regularly, yes. Herbal teas and mixtures consumed on a daily basis are also included in the assessment. The same does not apply to a tea drunk occasionally, but if you are in any doubt it is appropriate to mention it.
If my physician does not approve, do I have to stop my supplement?
The decision to stop is also made through a physician’s assessment. For some products it may be appropriate to use them for a certain period, and for others to stop them gradually. Do not make a sudden change on your own initiative.
Should I stop my supplements before a blood test?
This depends on which investigations are to be requested. You may be asked to stop some supplements for a period before certain tests. Ask about this when you make your appointment or when investigations are requested; do not stop them on your own initiative.
How do I find out whether I have a deficiency?
Through an examination and, where necessary, laboratory assessment. Which levels are to be checked is determined by the physician according to your symptoms. The same screening list is not applied to everyone.
Can I use a product I read about on the internet?
You are advised to consult your physician before using it. Health claims appearing in a product’s promotion may be contrary to the legislation, and the product’s contents may not be limited to what is on the label. Particular care is needed with products brought in from abroad and with mixtures whose contents are uncertain.
Sources
- Ministry of Health of the Republic of Türkiye, Turkish Medicines and Medical Devices Agency, Sağlık Beyanı (Gıda ve Takviye Edici Gıdalarda Sağlık Beyanı Kullanımı Hakkında Yönetmelik, Official Gazette 20 April 2023 / 32169). https://titck.gov.tr/faaliyetalanlari/denetim/saglik-beyani (opens in a new tab)
- World Health Organization, Traditional medicine questions and answers page, 28 November 2025. https://www.who.int/news-room/questions-and-answers/item/traditional-medicine (opens in a new tab)
