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Fillers in Vitamins and Supplements

Fillers in Vitamins and Supplements

Manufacturers of vitamins and supplements are required by law to list on their labels which vitamins and minerals they contain and in what quantities. However, if you look closely, you’ll notice a section called “Other Ingredients.” These ingredients do not have any quantities listed, nor is there any indication as to what they actually do.

These “Other Ingredients” are known as fillers and excipients. They all have a purpose, often optimizing the manufacturing process or binding the supplement together. With that being said, do they REALLY need to be present in your vitamins and supplements, and can they actually HARM you? Unfortunately, the answer isn’t black and white, so we would like to educate you on some of the most common fillers and excipients that manufactures use.

Why Do Manufacturers Use Fillers and Excipients?

Fillers and excipients fall into several categories, and many may fit into more than one category. The most common types are:

  • Binding agents: These are used to hold tablets and capsules together, so they don’t crumble apart.
  • Fillers: These add bulk to supplements, so that your capsules don’t appear to be only half full.
  • Flow enhancers and lubricants: These help to prevent supplement ingredients from clumping together and sticking during the manufacturing process. This often helps to lower the cost of supplements significantly.
  • Coatings and glazes: These also help to hold supplements together and make them easier to swallow.
  • Preservatives: These help to extend the shelf life of supplements.
  • Colors: These improve the appearance of the supplements.
  • Flavors and sweeteners: Most common in chewable and liquid supplements, these improve the taste of the product.

We have taken the liberty of putting together a list of the most commonly used fillers and excipient, as well are their uses. Our goal is that you become familiar with these ingredients so that you can make the best decisions for yourself when selecting vitamins and supplements for purchase.


Cellulose is a popular binding and coating agent. It is a naturally occurring organic compound found in the cell walls of plants. This makes it a popular choice for vegetarian and vegan supplement manufacturers that want to avoid using animal-sourced ingredients. Cellulose is also a popular bulking agent, because it takes up a lot of space without adding any additional calories. Humans lack the enzymes necessary to absorb cellulose, so it is not absorbed by the body and is considered a type of dietary fiber. It is considered safe for human consumption.


Gelatin is another popular capsule coating and binding agent. It is derived from animal sources, usually pigs and cows, so vegetarians and vegans will want to avoid any supplements containing it. If you don’t have these restrictions, gelatin is considered safe for humans, though consuming high levels of it may cause gastrointestinal distress.

Stearic Acid

Stearic acid is a naturally occurring fatty acid found in meats, eggs, butter and even chocolate. It’s a popular supplement ingredient because of its lubricating qualities, which help supplements readily flow through the manufacturing process without clumping or sticking to machinery. Because it is a saturated fat and because of its close relationship to magnesium stearate (see below), stearic acid is often given a bad rap, but it likely isn’t something to worry about if you come across it in your supplement.

Magnesium Stearate

Magnesium stearate is another popular flow enhancer and binder, made by combining magnesium with stearic acid. It is arguably the most controversial of all the excipients listed here, and that’s thanks to one 1990 rat study. The study was actually looking at stearic acid and claimed that it suppressed T cells in rats, a central part of the immune system. This reputation was also passed on to magnesium stearate, but subsequent research has indicated that humans may not experience this same effect.

Silicon Dioxide

Silicon dioxide’s ability to absorb moisture makes it a popular anti-caking agent and flow enhancer. It’s naturally found in sand, which may not sound like something you want to put into your body, but there’s no evidence to suggest that it reacts or interferes with anything inside your body.


Carrageenan is derived from red seaweed and is used as a vegan thickening agent. That all sounds great, but some studies have suggested that it can cause severe gastrointestinal distress and inflammation, so it’s best avoid it if you can.

Potassium Sorbate

Potassium sorbate is a natural salt that’s often used in supplements to help preserve them and extend their shelf life. Some people do not like potassium sorbate because it is often manufactured synthetically, but the Food & Drug Administration (FDA) considers it safe to eat. However, some people have a sensitivity or allergy to potassium sorbate which causes nausea and indigestion.

Titanium Dioxide

Titanium dioxide is a popular whitening agent used to improve the look of supplements. It carries no other benefit, and it is considered possibly carcinogenic by the European Chemicals Agency and the Canadian Centre for Occupational Health and Safety.

Hydrogenated Oil

Some supplements also have fillers such as hydrogenated oil from genetically-modified (or non-organic) soya bean. It’s been known to cause cardiovascular problems, diabetes, nervous system problems, and non-absorption of essential fatty acids. Hydrogenated oil, like trans-fat and solid fat, increases low-density lipoprotein (LDL, or ‘bad’ cholesterol) and decreases high-density lipoprotein (HDL) which results in coronary heart disease (CHD).

Artificial Colours and Flavours

These ingredients are included to enhance the look and taste of supplements. Although they are generally considered to be safe, there is some speculation that these ingredients may be harmful to the body, so it’s best to avoid them whenever possible.

In Conclusion = READ THE LABEL!

Not all fillers and excipients are harmful, but that doesn’t necessarily mean that you need to be consuming them either. Before purchasing a supplement, look closely at its Supplement Facts, particularly the “Other Ingredients” section, and select one that feels right for you!

The Organic Grocer is proud to offer FREE 10-minute health consults with one of our in-house Registered Holistic Nutritionists. To schedule an appointment or to learn more, please click here

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