What Are Excipients?

2 min

When reading the back of food supplement labels, you may notice that a list of other ingredients is listed under the term ‘excipients’. Excipients are inactive ingredients which are added to supplements to help the manufacturing process and stabilization. Sometimes, the ingredients creating the capsule shell are also mentioned here.

But rather than being a negative feature within a capsule, these supplementary, non-medicinal ingredients play a critical role in ensuring that supplement products are of consistent and reproducible quality.

Why Do We Need Excipients in Supplements?


Fillers are usually used as bulking agents, adding substance so that the size of a capsule or tablet is filled to the correct proportions of the capsule shell. This helps to make even the smallest active ingredients easy for people to consume.

Trace and micro ingredients, such as chromium, selenium, iodine, folic acid and biotin are measured in micrograms which can be very difficult to see with the naked eye. Even if placed within the smallest capsules available would appear virtually empty.

Supplement manufacturers use fillers to make dosage forms a reasonable size, with common fillers including starch, calcium, salts and lactose.


When binders are used within a formula, they provide a way of holding the ingredients within a supplement together. Without binders, tablets and pressed supplements would easily split or crumble.

Binders are also used to add volume to low active dose tablets. Most binders are usually derivatives of sugar, but some are made of ingredients such as cellulose, a simple wood pulp derivative which is sourced from vegetarian sources and becomes a non-digestible fibre when consumed.

Flow Agents

Flow agents are ingredients added to supplements to manufacture efficiently. These ingredients usually consist of powder excipients such as non-toxic lubricants and anti-caking agents which are used to help capsules and tablet products flow through processing steps with minimal resistance, making the entire process more efficient.

While flow agents are not strictly necessary, some supplements can’t be made without them, but they are usually kept to low levels of less than 1% within a blend.

Flow agents help in the following ways:

  • They help to ensure the right amount of active ingredients are placed into each capsule, assuring quality control.
  • They allow tablets to be compressed and ejected without sticking the equipment, resulting in products of high physical quality.
  • They serve as densifiers, helping particles stick together. This results in smaller capsules or tablets.
  • Overall, they help to keep the cost of manufacturing supplements down, making supplements more affordable for the end consumer.


Acidulants are only used within liquid supplements such as oil softgels and liquid capsules, especially those containing water, which tends to be an ideal environment for microbial growth. Acidulants are used to prevent unwanted bacteria from forming.

Acidulants are safe for human consumption and are typically found within fruits and vegetables. These include citric acid, malic acid, tartaric acid and aspartic acid.


If a supplement has the word ‘fast acting’ on the label, there is a high chance that it contains disintegrates. These allow for the rapid breakdown of capsules or tablets within the digestive tract, so the active ingredients within the supplement can be quickly released and absorbed into the body. These excipients are formulated to instantly dissolve on contact with water and other liquids.

Supplement Factory

Written by Supplement Factory

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