Young african woman holding up a nutritional supplement

Understanding supplement labels and formulations

Understanding supplement labels and formulations can often be challenging and with so many supplements to choose from, plus the wealth of information on each product label, it can be difficult to know where to start and what to look for.

In this week’s blog we will aim to simplify some of the information for you and pick out some key points to help you make an informed and educated choice when buying supplements. 

Supplement regulations

In the UK, food supplements are required to be regulated as foods and are subject to the provisions of general food law. Food law regulates the content, labelling and promotion of food products, including food supplements and it remains the responsibility of the manufacturer, importer or distributor to comply with all relevant legislation.1 Validating the company is important in this respect. 

The supplement label

There may be a few variations between different companies but collectively the supplement label should include relevant information about the supplement, including:

  • Conditions for use – this includes information on the recommended daily dosage and a warning not to exceed this. Other specific instructions may be included (i.e. take with food or on an empty stomach). It is important to follow these recommendations unless advised otherwise by a doctor or practitioner.
  • Presentation – Different presentations include tablets, capsules, liquids, gummies or powders. As a rule, the presentation used is usually one that is most suited to the materials within. It might be worth considering which presentation is the most suitable to your needs. If ease of intake is a factor, then a powder may be the preferred choice if possible, or smaller capsules/tablets. If the supplement is for a child, then gummy form may increase compliance. Other factors to be mindful of include levels of excipients, taste, and size. If organic is important to you, then products are almost always in capsules as there are so few excipients approved for organic production. 
  • Ingredients list and source of the nutrient. Every ingredient in a product needs to be declared and should be in weight descending order. The ingredients should also be in their scientific name. The ingredients list will also give details of any excipients used.

The only ingredients permitted to be used in supplements in the UK are those with approval and those that have grandfather rights by virtue of long continued use.

  • Amount of each ingredient – the amount of any vitamin, mineral or other substance with a nutritional or physiological effect must be listed. The most common units of measurement are milligrams (mg), micrograms (mcg or ug), grams (g) and international units (IU). 
  • Nutrient reference values (NRVs) – indicates the levels of vitamins and minerals needed to avoid deficiency (discussed further on). The percentage of the NRV present in the product should also be displayed on the label.
  • Contraindications – check if any medication contraindications are listed. If in doubt, ask your GP of local pharmacist. Contraindications should have been thoroughly researched by the company. 
  • Allergy warnings – 14 allergens are required to be declared by food law. These should be displayed in bold or underlined.
  • Information about the company – the company name and address should be displayed on the label and will enable you to do a little homework on the company to make sure it is reputable. Questions to consider:
    • Do they have a team of nutritional therapists or medical doctors responsible for formulations?
    • Do they adhere to strict GMP guidelines, with ingredients and the manufacturing plant similarly accredited?
    • Are there published reviews from an independent source?
  • Permitted health claims A supplement company must not make any unapproved health claims. Products must meet certain conditions to be able to use a health claim and they must comply with the nutrition and health claims register. As of January 2021, the UK Nutrition and Health Claims Committee (UKNCC) advise the UK government on the scientific evidence behind new nutrition and health claims.2

Examples include:

    • Vitamin C contributes to the reduction of tiredness and fatigue
    • Vitamin D contributes to the normal function of the immune system
  • Free from claims – these claims require strict controls of ingredients, how they are handled and how they are prepared. A free-from claim is a guarantee that the food is suitable for all with an allergy or intolerance. Examples include, ‘free from wheat’ and ‘free from dairy’.
  • Best before date – signifies that the supplement may lose potency beyond this date and will not be as effective. 
  • Organic – In order to make an organic claim on a label, a food manufacturer must be registered with a recognised organic control body. Plus, all the raw materials and manufacturer must be accredited by the same organic control body. 

Supplement formulations

It is worth making sure that the company has medical doctors and/or nutritional therapists on board to help with formulations to give you peace of mind. It may be useful to consider the acronym – TLC – Totality, Levels and Correct form. 

T – Totality of nutrients

A formula should contain the totality of nutrients needed for the purpose of the formula. For example, a multivitamin and mineral should contain the full range of vitamins and minerals needed for health. Some of us may also require more targeted support for digestive health issues, joint complaints, or to support cardiovascular health, for example. Check that targeted supplements have been formulated to support specific health needs within the body and the included ingredients are supported by research.

L – Levels of nutrients

The levels of nutrients in formulations should be at both safe but efficacious levels and at levels appropriate for intended outcome. The term ‘nutrition gap’ refers to the difference between the levels of nutrients the average person is obtaining from food, and those nutrient levels identified as being needed for optimal health.

A safe and effective level of nutrient to look for is therefore the level needed to elevate intake from an average diet to optimum.

You can find data on the nutrition gap in our booklets The Nutrition Gap and A Guide to Choosing Health Food Supplements. Bridging this nutrition gap is a safe, effective and purposeful approach to supplementation.

Currently, the UK industry works to safe upper levels (SULs) and guidance levels (GLs) established by the 2003 report by the Expert Group on Vitamins and Minerals and the EU NRVs of vitamins and minerals. The NRV values are set by law but as yet there are no legally set maximum permitted levels. The legal requirement is that all supplements are safe for use and fit for purpose.

You will often see levels of nutrients at higher doses than the set NRV. When the National Academy of Sciences drew up the NRVs, it never claimed these represented nutrient intakes designed to achieve optimal health. They were never intended as any more than a safety net, with the specific purpose of preventing diseases of overt deficiency.

The two main problems with NRVs are:

  • they are average values which do not consider the needs of individuals
  • the typical vitamin or mineral dose sufficient to prevent overt deficiency-states is always short of the amount needed for optimum health

If an ingredient is missing a % NRV or you see asterisks on the label, it indicates that a value has not been established.

Note – If you are taking more than one supplement do always cross reference the levels of the same nutrient in all products to make sure you are not tipping balances into excess. If in doubt check with your practitioner 

C – Correct form

Nutrients must be in the correct form for bioefficacy; this means the nutrient easily enters the body circulation with beneficial outcome. Supplements which provide nutrients in the same form as they occur in food are often best and if this isn’t possible then choose a compound which has good bioavailability and efficacy.

Food state and wholefood supplements

The best products are usually those that fit normal food metabolic pathways and thus are constructively helpful to the everyday working, function, repair and regeneration of tissues and organs.

Food state and wholefood nutrients are highly complex structures that come complete with the associated food factors and other phytonutrients with which they occur in wholefoods.

This total food complex ensures they are recognisable as food by the human body and optimally utilised.

Often it is the associated food components in the complex that are responsible for the retention and utilisation of the primary nutrient, and this ensures a beneficial metabolic use. Products which use nutrients from food will state on the label – vitamin C from acerola, beta carotene from carrots, calcium from calcified seaweed, iodine from kelp, vitamin D from lichen, omega 3 from algae, for example. 

Isolated nutrients

Conversely, many supplements on the market contain isolated nutrients, which as the name suggests, are without the other food factors that ensure recognition by the body.

These isolated nutrients can be rapidly excreted. This is witnessed particularly in the metabolic difference between food vitamin C and ‘isolated’ ascorbic acid.

The former is absorbed, retained and used optimally, whilst the latter, although bestowing antioxidant properties, is excreted more rapidly.

It is important to mention that all substances will eventually get into the body through a concentration gradient, but this does not mean that they will be optimally utilised. This is why one often sees high doses of isolated nutrients being sold, simply because this is necessary to get the nutrient into the body.

In contrast, this is also the reason why when using a nutrient in a form that fits into normal metabolic pathways, smaller levels will be sufficient for bioefficacy. The potency has much more to do with synergy than with actual nutrient levels.

Methylated nutrients

There are times however when reduced or methylated forms of nutrients are the most bioeffective in individuals as some nutrients such as the B vitamins and magnesium are not found in high levels in plants and other foods. 

Bioeffective nutrients

Providing nutrients in their most bioeffective form is a key consideration when looking more closely at formulations. For example:

  • Many vitamin B12 products provide B12 as cyanocobalamin, which needs to be converted to the active form within the body. Formulations using vitamin B12 in its most active forms (methylcobalamin and adenosylcobalamin) make it universally bioeffective (biologically active and effective)
  • Methylfolate has greater activity in the body than folic acid and is a methylated, stable, and active form of folate for easy utilisation by the body. It can bypass the folic acid metabolism cycle, which is beneficial if you have an MTHFR mutation (approximately 40% of the population)
  • Both cholecalciferol (D3) and ergocalciferol (D2) are effectively absorbed into the bloodstream; the liver however metabolizes them differently. D3 is more effective at raising serum 25(OH) D concentrations and is more bioavailable3
  • Vitamin K1 is poorly absorbed by the body, whereas K2 is more bioavailable4


Minerals are inorganic elements that come from the soil and water. They are difficult for the body to absorb without being attached to an organic compound or other substrate or carrier.

Chelated minerals – The combining of inorganic minerals with organic compounds happens through a process called chelation.

‘Organic’ in this respect refers to a molecule that contains carbon. Both amino acids and organic acids can be used as natural chelators so that the two do not disassociate in the digestive system, essentially protecting the mineral so it can be absorbed. They also do not need as much stomach acid to be effectively digested.

Well-formed mineral chelates effectively mimic what nature does in protecting the mineral. As chelated minerals do not disassociate as they pass through the stomach, they tend to be gentler on digestion and less likely to cause stomach upset and other side effects. The effect of chelating agents however generally depends on the stability of the chelates in the intestine and their solubility.

Glycine, for example, is a small amino acid, making it easily absorbed through the intestinal wall. It also forms stable bonds with minerals and so doesn’t release them before they can be absorbed.

Magnesium bisglycinate is an example of the mineral magnesium chelated with glycine.

Citric acid is an example of an organic acid which when bound to magnesium makes magnesium citrate.

Other than increased absorption, chelation can also be helpful when addressing specific concerns. For example, magnesium, in bisglycinate form, is particularly helpful for supporting sleep and relaxation. Magnesium citrate may help to increase intestinal motility.

Non-chelated mineralsConversely, many of the minerals used in supplements are inorganic forms, such as sulphates, oxides, and carbonates. These non-chelated minerals are considered inorganic because they are not attached to a carbon-containing molecule.

Calcium carbonate is an example of a non-chelated mineral. Non-chelated minerals may cause nausea and other side effects, especially if taken on an empty stomach. 

Organic minerals – Only plants can convert inorganic minerals into their organic form; we therefore need to consume the plants or the animals that have eaten the plants.

Organic minerals are plant-based minerals and are usually more bioavailable. For example, calcified seaweed has a porous and hydrolysed surface area because of years in the ocean; this helps it to be very soluble in the acidic conditions of the stomach.

Calcium carbonate conversely is not soluble. Kelp and seaweed are also the most reliable natural source of iodine.

Supplement excipients

It is always preferable to choose a supplement that contains minimal excipients. Although these excipients may be necessary in some products, it is recommended to avoid those that contain a long list.

Excipients are materials that facilitate the making of the ingredients into a finished product; they are usually inactive and do not contribute any form of nutritional value to the product. They do however often play an important role in ensuring that supplements are of a consistent and reproducible quality.

The type of excipient used is determined by the objective and there are various types of excipients used in the manufacture of supplements. Excipients generally fall into several categories which include binding agents, coating and glazing agents, emulsifiers, disintegrates, flow agents, preservatives and fillers.

If you are only taking one or two supplements with low levels of excipients then this is unlikely to cause any issues. However, always be mindful if taking large numbers of supplements as the total level of excipients being ingested can escalate.

Always cross reference excipients to make sure you know what you are taking. As with any ingredient, some are better than others so always be mindful of this.

Excipients used in food supplements must be permitted for use. For further details please refer to our booklet Your guide to choosing health food supplements.

All of our blogs are written by our team of expert Nutritional Therapists. If you have questions regarding the topics that have been raised, or any other health matters, please do contact them using the details below:
01684 310099

Find out what makes Cytoplan different



Last updated on 10th April 2024 by cytoffice


We'd love your comments on this article
It's easy, just post your questions, comments or feedback below

Names will be displayed as entered. Your email address will not be published. Required *