Using food supplements

Food supplements and their use

Food supplements are widely available in various forms that can resemble medicines. Vitamins and minerals may be available as both medicines and food supplements.

To understand the quality, safety, and regulatory differences between food supplements and medicines, see our article:

• Understanding food supplements

Food supplements are generally safe for most people when used as the manufacturer intended: to supplement the normal diet. NHS England recommends that patients buy their own vitamin and mineral supplements for this purpose.

Foods for Special Medicinal Purpose (FSMP) are manufactured specifically for their designated purposes, as defined on their packaging. They are essential for patients requiring targeted nutritional support for some medical conditions.

Treating a medical condition or vitamin deficiency is a higher-risk situation than maintaining dietary sufficiency. A medicine should usually be used as medicines are regulated to higher standards than food supplements. However, a food supplement might be used if:

• a medicine is unavailable
• patient-specific factors make an available medicine unsuitable, such as allergy to an excipient

Patients may also purchase food supplements and complementary therapy products without seeking medical advice. Our guidance on Advising on complementary products and conventional medicines explains more about managing this safely.

Legal and governance responsibilities

Food supplements may be available more cheaply than medicines, so using them as a substitute can be appealing. However, they are not medicines, and their use for medicinal purposes carries similar legal and professional implications to the supply of an unlicensed medicine.

Royal Pharmaceutical Society guidance (access for members only) states that a pharmacist shares accountability with the prescriber for supplying a ‘special’ (unlicensed medicine) to a patient. The same principle will apply when supplying a food supplement to a patient for medicinal purposes. Pharmacists should liaise with the prescriber and the patient or carer to ensure that a food supplement is the most appropriate choice. They should also ensure prescribers and patients understand the differences between medicines and food supplements.

The Medicines Act states that products sold or supplied against a prescription by a pharmacist must be ‘of the nature and quality demanded’. It must therefore be suitable for its intended use, and the prescriber must be aware of its nature.

All organisations should have a policy covering the use of food supplements for medicinal purposes. This should include guidance on how to manage each stage of the process safely. Include outsourced supply functions, where relevant.

Factors to consider

Food supplements may contain significantly different amounts of the active ingredient than is stated on the label, or may contain undeclared ingredients. The ingredients may also change without notice. This introduces additional risks compared to using a medicine. When deciding whether the use of a food supplement is safe and appropriate a risk-based evaluation is needed, taking several factors into consideration.

Potential for toxicity

A food supplement may contain more or less than the amount of active substance stated on the label. If a supplement contains more than the stated amount of active substance with a high toxicity index there is an increased risk of patient harm. If toxicity could occur, consider how reversible and easy to treat it would be.

Example

Excess vitamin D in food supplements has caused toxicity. A published review article found that variations in the content of vitamin D supplements are not uncommon. In 2025 the Food Standards Agency recalled two supplements containing excessive amounts of vitamin D.

Conversely, vitamin C is not associated with significant toxicity even at high doses, so the risk of overtreatment is low.

Risk of undertreatment

If a supplement contains less than the label claims, treatment may be unsuccessful. Consider the seriousness of the condition being treated, and the consequences to the patient of receiving a lower dose than expected.

Detectability of harm or ineffective treatment

Consider how likely it is that under- or over-treatment will be detected so that potential patient harm can be addressed in a timely manner. We discuss patient monitoring in the section about managing food supplements safely.

Necessity of treatment

Consider the risk of leaving the condition untreated. The risks of non-treatment may or may not outweigh the risks of using a food supplement.

Choosing a specific food supplement

If the benefits of using a food supplement outweigh the risks, a food supplement may be a suitable choice for the patient. The next step is to select an appropriate supplement.

Food supplements may be listed in the BNF, DM+D or in our Medicines Supply Tool, and may be on NHS medicines frameworks. They may also be available from medicines wholesalers. However, this does not mean that their quality has been assessed.

Quality considerations

Our article Understanding food supplements explains the quality differences between food supplements and medicines.

Lower regulatory standards apply to food supplements. It is therefore not possible to prove suitability of a food supplement in the same way as for a medicine. Nevertheless, steps can be taken to minimise risks and give confidence that the supplement has been manufactured according to at least UK food standards. These include purchasing from reputable suppliers within the UK.

Factors which may cause concern include, but are not limited to:

• supplements manufactured outside the UK or EEA, which may not comply with UK food standards
• presence of unfamiliar inactive ingredients which may not be permitted in UK foods or medicines
• laboratory results or certificates provided are not from an accredited laboratory, or give the impression of being inauthentic

Formulation considerations

As with unlicensed medicines, it is important to understand all the food supplement’s ingredients to ensure it is suitable for the patient or patient cohort. Food regulations require that ingredients must be stated on the label, but quantities of ingredients other than the ‘active’ substance may not be clear.

The Food Standards Agency has a list of approved additives for food.

Example

An imported oral iron food supplement was identified as containing the preservative bronopol, which is not used in oral medicines in Europe.

Managing food supplements safely

If a food supplement is used for a medicinal purpose, steps may be needed to mitigate the additional risks arising from not using a medicine. Develop a plan proportionate to the risks and benefits of each individual case.

An approach similar to managing the use of unlicensed medicines can be used. Refer to our article Using unlicensed medicines for further advice.

Ordering and receipt

Ensure you have a purchasing specification including but not limited to:

• labelled dose
• form
• required ingredients
• ingredients known to be unacceptable based on patient requirements

Suppliers or manufacturers may make changes to products without communicating this to customers. Check each delivery against the purchasing specification. Review the label to ensure it will not mislead the patient.

Stock control

Ensure your stock management and supply systems differentiate between food supplements and licensed medicines. This will ensure that food supplements are not supplied when a medicine should be supplied.

Example

When an animal-derived vitamin D medicine and a vegan food supplement are both stocked it is important to ensure the correct product is dispensed for the patient.

Monitoring and reviewing the patient

Organisations should continuously review the use of a food supplement rather than a medicine.

Depending on the likelihood or consequence of under-dosing or over-dosing, it may be necessary to monitor the patient’s condition and response to treatment more closely.

Reviewing the product

Review the continuing suitability of the purchased food supplement regularly, considering:

• whether it has been successfully used with no reported adverse effects
• whether there is a more suitable product available, for example a medicine, or a more suitable food supplement
• the experience of purchasing the food supplement
• quality concerns such as suspected incorrect content, poor labelling, or other defects

Record-keeping

Keep records of the receipt and supply of food supplements for a medicinal purpose the same way as for unlicensed medicines. Consult our articles on Retaining and storing pharmacy records in England for guidance.

Finding out about safety issues

Defective food supplements will be recalled by the Food Standards Agency. It is possible to subscribe to the Food Standards Agency’s news and alerts but most alerts will not involve food supplements.

Royal Pharmaceutical Society members can sign up for RPS pharmacy alerts, which include alerts about food supplements likely to interest pharmacists. Community Pharmacy England may add food supplement alerts to their website.

Reporting concerns

Report any problems or quality concerns with food supplements to the Food Standards Agency. Consider also sharing information with pharmacy networks.

Supply and reimbursement

Food supplements will usually be reimbursed if prescribed on FP10 provided they are not listed in Part XVIIA of the Drug Tariff. However, NHS Prescription Services may investigate the prescribing of food products unless they are listed as a ‘Borderline Substance’ in Drug Tariff Part XV.

Food supplements cannot be supplied or administered under a Patient Group Direction (PGD) or any of the exemptions to the Human Medicines Regulations.

Our guidance on transfer of care for unlicensed medicines may be useful if the patient may need further supplies from a different organisation.

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