Supplement Ingredients, Part I: Inactive Ingredients

By Ashley Watson

inactive-ingredients-3Have you ever looked at the label on a supplement and wondered why it contains inactive ingredients?

For instance, the label on a B-complex vitamin should list all of the different B vitamins that are included in the product, such as Thiamin, Riboflavin (Vitamin B2), Niacin, Folic Acid, Vitamin B12, Biotin, and other added minerals.

Next to each ingredient you will find a number stating the amount of that ingredient. These are considered the “active” ingredients because they are intended to have a therapeutic effect.

Then you will see a list of inactive ingredients, sometimes listed as “other” ingredients. As a consumer, you probably want to know (and have a right to know) why these ingredients are included if they are not intended to be beneficial to your health. The answer is often simple. Most inactive ingredients are included to provide flavoring, to preserve the product, or to bind the ingredients together.

We have picked a few common inactive ingredients found in many vitamin and mineral supplements and divided them into categories depending on their function. Listed below each ingredient, you’ll find where the ingredient comes from and its uses.


The following ingredients are typically used to add flavor to the product or as a flavor enhancer, though they can be used for other purposes.


  • Derived from the pod of the tropical carob tree (locust bean)
  • Low fat alternative to cocoa powder that is used as flavoring or to color soft gels, which protects active ingredients from light

Cellulose, methyl

  • A fiber derived from plant sources
  • Used as product stabilizer, thickener, emulsifier or flavoring


  • Simple sugar (monosaccharide) derived from corn or isolated from refined sugar
  • Used as a sweetening agent because it absorbs more slowly from the GI tract than table sugar (sucrose)

inactive ingredientsMaltodextrin

  • Non-fermentable sugar obtained from cornstarch
  • Flow agent; stabilizer and thickener; improves texture; nutritive sweetener

Maltol, natural

  • Isolated from naturally occurring sources such as beech wood, pine needles, or chicory
  • Flavor enhancer


  • A sugar alcohol that is half as sweet as sugar
  • Sweetening agent and sugar substitute; adds moisture to products


Many of these ingredients are commonly used as preservatives in supplements, and some are used in foods as well.

Benzyl alcohol

  • Antimicrobial preservative
  • Preservative included in FDA inactive ingredient list used in foods


  • Occurs naturally in fats and oils
  • Preservative; adds moisture; sweetening agent

Potassium sorbate

  • Non-sodium salt of potassium; the mineral potassium combined with sorbic acid (synthesized or naturally occurring substance from berries)
  • Antimicrobial preservative widely used in foods

Sodium benzoate

  • Commonly used preservative
  • Antimicrobial preservative; flow agent

Binders and Flow Agents

inactive-ingredients-2Many inactive ingredients are used as flow agents, which help all the ingredients flow smoothly during the manufacturing process. Binders and stabilizers ensure that tablets do not break inside the bottle, and some of these ingredients are used to add moisture to the product as well.

Calcium stearate

  • Mineral calcium with stearic acid, a fatty acid derived from animal or vegetable sources
  • Flow agent and emulsifier

Cellulose microcrystalline

  • Fiber with increased water-solubility derived from plant sources
  • Tablet binder—ensures that tablets do not break apart in the bottle and, interestingly enough, also helps tablets disintegrate during digestion

Cellulose, powdered

  • Fiber derived from plant sources
  • Used as a stabilizer, thickener, or binder

Dicalcium phosphate

  • Inert naturally occurring mineral composed of calcium and phosphate
  • Tablet binder and sometimes used as a source of calcium or phosphorous

Glyceryl triacetate

  • Derived from fatty acids
  • Provides moisture, flavoring, and used as a flow agent; other form also used to coat and stabilize tablets to improve texture (glycerol monostearate)

Hydrogenated vegetable oil

  • Mixture of fatty acids taken from vegetable oil; processed for stability
  • Small amounts used as flow agent and as a tablet binder

Magnesium stearate

  • Combination of the mineral magnesium and stearic acid (a fatty acid)
  • Flow agent

Silicon Dioxide

  • Naturally occurring form of the mineral silica (sand)
  • Keeps ingredients from getting too sticky; used for flavoring, emulsifier, and adds moisture to aid in the formation of tablets

Stearic acid

  • A fatty acid derived from vegetable or animal fats
  • Emulsifier and flow agent

Xanthan gum

  • Polysaccharide produced through fermentation of a carbohydrate, then purified
  • Stabilizer and emulsifier

Next week, we’ll take a look at the differences between natural and synthetic ingredients and what that means for the consumer.

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