If you ever look at the list of ingredients on your supplement bottles, you’ll notice there’s always a section called “additional” ingredients. The question we answer is, what exactly is in that list?

The “additional” ingredients are also known as excipients. Within this post, we will define excipient, what excipients mean, and the most common excipients to look for.

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An excipient is any component, other than the active ingredients, that’s present in a supplement or drug.

What’s an excipient?

An excipient is any component, other than the active ingredients, that’s present in a supplement or drug. (1) Although excipients don’t have active effects, the formulation of many supplements requires the combination of active ingredients with some additional non-dietary ingredients during the manufacturing process and in the finished product. It’s even possible that an excipient is not present in the final product, but it may be an important part in a step of the manufacturing process.

Why are excipients in my products?

Excipients are often used to aid the manufacturing process, assist in product identification, and act as the carrier or as a component of the carrier of the active substance. (2)

They contribute to product attributes such as enhancing appearance, stability, bioavailability, and patient acceptability. Protecting, supporting and enhancing stability improves overall safety and function of the product during transport, storage, and use. Excipients often have more than one use as well!

Here are some excipient functions:

Acidifying/alkalizing agent
Aerosol propellant
Antimicrobial preservatives
Buffering agent
Bulking agent (freeze-drying)
Chelating/sequestering agent
Coating agent
Coloring, flavor, perfume

Emulsifying/solubilizing/wetting agent
Glidant, anticaking agent
Ointment/suppository base
Stiffening agent
Suspending/viscosity-increasing agent
Sweetening agent
Tonicity agent

Hand holding a supplement bottle with more bottles in the background

Excipients often have more than one use as well!

What are some commonly used excipients?

Magnesium stearate
Modified cellulose
Modified cellulose gum
Silicon dioxide
Soybean oil
Stearic acid
Ascorbic acid, a-tocopherol

Castor oil
Benzalkonium chloride
Boric acid
Macrogols (polyethylenglycols)
Benzalkonium chloride
Sodium metabisulphite
Propyl gallate
Sesame oil
Lanolin (wool fat)

What kind of regulations are there about excipients in products?

Non-dietary ingredients, including excipients, that are present in dietary supplements must comply with food additive regulations or be GRAS (Generally Recognized as Safe) for their intended use. (3)

Any non-dietary ingredient has to meet the following criteria:

  • A premarket approval based on data demonstrating safety
  • Both evidence of safety and a basis to conclude that this evidence is generally known and accepted by qualified experts
  • Regulations specifying the conditions under which the additive has been demonstrated to be safe and, therefore, may be lawfully used
  • Scientific evidence generally available to establish the safety of the substance for its intended use

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