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Top 4 Supplement Additives You Should Know About

Top 4 Supplement Additives You Should Know About

Many nutritional supplements contain additives or excipients. These additives do have a purpose which may be to act as fillers, binders, or flow agents. If they are present, then you will usually find them listed under “other ingredients” or “inactive ingredients” section. Here is a breakdown of what additives and excipients do and how they can affect your health.


Commonly referred to as bulking agents or carriers, fillers are used to increase the size of a tablet or capsule by adding substance. Supplement manufacturers use them because, without them, the pills can be tiny, difficult to handle, and nearly impossible to consume. Some ingredients like biotin have dosages in the microgram range which are thousandths of a milligram. Having fillers makes it easier to handle and take the supplement. Common fillers include calcium, carbonate, and cellulose.


Just like their name suggests, binders help to hold the ingredients in a supplement together. Without binders, a pill may break apart or crumble. Broken and jagged pills are uncomfortable to swallow. Ingredients that bind supplements together may also add weight or to allow for the inclusion of a combination of very small amounts of active ingredients. Common binders include gelatin, magnesium stearate, cellulose, and calcium carbonate.

Flow Agents

Flow agents, such as lubricants and anti-caking agents, are added to supplements to help them get through the manufacturing process as efficiently as possible. They prevent ingredients from clumping and sticking together and clogging the machinery. Flow agents are not always necessary, though in some cases they cannot be avoided. For example saw palmetto is a very viscous and sticky substance that machines have problems handling. In this situation flow agents would be necessary. Common flow agents include magnesium stearate, stearic acid, and silicon dioxide.

Coatings and Glazes


A coating or glaze, such as gelatin, prevents the tablet from falling apart and can make it easier to swallow. It may also protect ingredients from heat or moisture. Coatings also protect the nutrients inside the tablets from oxidizing and becoming less effective. Certain products also feature an enteric coating which controls the rate at which the ingredients are released into the digestive tract, thus protecting the contents inside from stomach acid. Most enteric coatings are safe and non-toxic but certain companies will opt to use the cheapest ones. Cheaper coatings can contain phthalates which are categorized as endocrine disrupting substances. If the product you’re using has an enteric coating, make sure it is phthalate-free.


Preservatives are added to nutritional supplements to help them maintain their original quality and freshness over time and to prevent any changes taking place that would make the supplement unpalatable or unsafe for consumption. For example, antioxidant preservatives may be used to inhibit degradation due to oxidation, and antimicrobial preservatives may be used to inhibit the growth of pathogenic microbes.

Consuming nutrients that contain artificial preservatives, like sulfites and nitrites, may cause allergic reactions in people who are sensitive to these substances. Natural preservatives include vitamins A, C, and E, and amino acids such as methionine and cysteine. 

The 4 Most Common Supplement Additives

Now, let’s look at four of the most common additives you will find in nutritional supplements and see exactly why they are used & whether they are safe.

Common Additives


Maltodextrin is commonly used in supplements as a filler. It is a form of carbohydrate derived that is easily digested.  Plants produce glucose using water, carbon dioxide, and light. They store excess glucose molecules in the form of starch. Maltodextrin is made from tapioca, rice, wheat, potato starch, or corn. Depending on the source maltodextrin can be genetically modified.

Maltodextrin is made through a process known as partial hydrolysis using starch, enzymes, and water. This process breaks down longer chains of starch into shorter chains of carbohydrates consisting of glucose. Glucose is a perfectly safe and universal food source for all forms of cellular life.

All forms of maltodextrin are gluten-free, even that which is derived from wheat. When it is derived from a wheat source, the gluten is removed. Because it undergoes hydrolysis, the maltodextrin derived from wheat contains no gluten. Hydrolysis breaks up all proteins like gluten. However, you should still avoid wheat-based maltodextrin if you suffer from Celiac’s disease, so as not to risk any potentially adverse effects.  

DrFormulas uses non-GMO maltodextrin sourced from rice or tapioca.

Magnesium Stearate

Magnesium stearate is a white, water-insoluble powder made from combining stearic acid with a magnesium ion. It is commonly used in nutritional supplements as a binder and a flow agent, as it keeps ingredients together while preventing tablets from sticking to each other or the machines.

There are currently a lot of misconceptions about magnesium stearate. One of the main criticisms is that magnesium stearate has a harmful effect on T-cells—the white blood cells which protect your body from pathogens. There are a number of problems with the clinical studythat is usually used as evidence for this conclusion. Firstly, the experiment used T-cells taken from mice. Secondly, the cells were bathed not with magnesium stearate, but steric acid. Finally, the study is completely unrelated to steric acid in your diet, which under usual conditions, does not bathe your T-cells. In studies involving human subjects, stearic acid was found to have beneficial effects on T-cells2.

Another concern about magnesium stearate is that because it is often produced from cottonseed oil, it may be highly contaminated by pesticides. In its manufacture, magnesium stearate goes through a rigid process of purification and refining before it is used in nutritional supplements. Furthermore, there are no available reports that demonstrate or suggest that magnesium stearate is contaminated with residue from pesticides.

Some people have suggested that since cottonseed oil is often genetically modified, it could be dangerous for consumers. However, the composition of stearic acids remains the same whether it is derived from a genetically modified cotton plant or from organic beef tallow.

For people who are concerned about the tiny amount of steric acid that may be contained in a nutritional supplement, it should be noted that a far greater quantity is consumed in the average American’s daily diet from sources such as beef, poultry, cocoa butter, cheese, and dairy desserts3.

Bear in mind that the FDA recognizes magnesium stearate as “generally recognized as safe” (abbreviated as GRAS). What this means is that there is no available evidence or information which suggests that there is any reason to suspect magnesium stearate is dangerous to consumers at the level at which it is currently being used; neither are there any available reports of side effects.

A note from Dr. Do:

I honestly believe that the bad press magnesium stearate has been given is unwarranted and is part of a marketing push by other supplement companies. Magnesium stearate is actually good for you. Magnesium stearate consists of two components, a magnesium ion and a molecule of stearate which is derived from stearic acid. Stearate is a fat that is which is easily absorbed and broken down by the body. Scientists have followed the body's metabolism of stearate and found that it is readily metabolized by the body into oleic acid4.

Oleic acid is an unsaturated fat which means that it is better for you than saturated fat. In fact, one study on stearate in the American Journal of Clinical Nutrition found that stearate was associated with reductions in low density lipoproteins (LDL, or bad cholesterol)5.

As for the magnesium in magnesium stearate, magnesium is an essential mineral which can be absorbed and utilized by the body. An estimated 75% of the population consumes magnesium below the Recommended Daily Allowance (RDA).

Companies touting magnesium stearate are doing so irresponsibly and without merit. Magnesium stearate is good for you for two reasons:

  1. It lowers LDL or bad cholesterol
  2. It is a source of magnesium, which most people do not consume enough of

Silicon Dioxide

Silicon dioxide, also known as silica, is another flow agent. It prevents ingredients from clumping together. Some consumers express concern that silica is harmful to the human body. Silica is non toxic if consumed by mouth. . Workers who perform sandblasting are exposed to aerosolized silica which then deposits in the lungs.

Our primary concern related to silicon dioxide is its deficiency. Silica is found in natural sources like cruciferous vegetables, bellpeppers, and brown rice, which would seem to suggest it’s quite safe. In addition, we need silica in our diets, along with calcium, to help our bones and connective tissue develop and stay strong. A deficiency in this mineral can cause brittle bones, dry skin, splitting nails, and hair loss6.

But how much silica is safe? The recommended daily amount for silica is 9-14 milligrams7, and the average American consumes 25-50 milligrams per day8. Research shows that there is no need for concern because we don’t store silica that we eat is readily passed through the body or is flushed out by the kidneys9. Also, the FDA recognizes silica as a safe food additive.

Additives You Should Avoid

Additives to Avoid

Titanium Dioxide

This is one excipient that you are better off avoiding. It is used as an artificial color in some nutritional supplements. This white powder is a natural oxide of titanium, and in spite of the fact that only very small amounts are used in supplements (less than 1% of the total formulation), it has been implicated in numerous health concerns. Some of the reported side effects include:

  • Dry skin
  • Acne
  • Contact dermatitis
  • Inflammation of hair follicles
  • Skin irritation

 Artificial Colorings

Artificial food colorings are commonly used in nutritional supplements. They are added to nutritional supplements to help prevent the tablets losing color due to exposure to air, varying temperatures, moisture, and light, as well as to enhance natural colors.  However, there is growing concern about some artificial food colorings, may impair learning in children already diagnosed with attention-deficit hyperactive disorder (ADHD)10. Other than making them look “better,” artificial colorings serve no purpose in nutritional supplements, except perhaps to hide the fact that the potency of their active ingredients may have been degraded by external conditions.

The FDA has concluded that food dyes may not cause ADHD but kids with ADHD may be sensitive to them11. That being said, the FDA considers the following artificial colors to be safe12:

  • FD&C Blue No. 1
  • FD&C Blue No. 2
  • FD&C Green No. 3
  • FD&C Red No. 3
  • FD&C Red No. 40
  • FD&C Yellow No. 5
  • FD&C Yellow No. 6

Final Say on Additives

When it comes to additives, it is important to remember that most inactive ingredients in nutritional supplements are present in very small amounts; often so small that they represent less than 1% of the total formula. Every body is unique and responds and reacts a little differently to different things. When taking nutritional supplements, you should also take into account what combination of supplements you are taking and any other medications you may be taking at the same time. Prescription and over-the-counter medications can sometimes interact with nutritional supplements just as they can with each other. You also need to think about how these could be accumulating in your body over time. For these reasons, it is always a good idea to discuss the medications, vitamins, and supplements you are taking with a healthcare professional on a regular basis.