Microcrystalline Cellulose vs Magnesium Stearate: Pros & Cons

In the intricate world of dietary supplement formulation, the choice of ingredients goes beyond just the active compounds. Excipients, the inactive substances used primarily to confer a suitable consistency to the formulation, play a pivotal role in the tablet-making process. Among these, microcrystalline cellulose and magnesium stearate often come to the fore, serving as critical agents that influence flow and compression.

But how does one decide between them, or discern when they might best be used in tandem?

In this article we will explore these two key excipients, understanding their advantages, potential drawbacks, and how they fit into the bigger picture of supplement manufacturing.

Both microcrystalline cellulose (MCC) and magnesium stearate are commonly used in the formulation of dietary supplement tablets. They serve different primary purposes in the formulation process, but they can influence the flow properties of the granules or powders being tableted.

Let’s look at the pros and cons of each with respect to their use as flow agents:

Microcrystalline Cellulose (MCC)


  1. Binder and Disintegrant: MCC is not only a flow agent but also acts as a binder and a disintegrant, which means it helps to hold the tablet together and aids in its breakdown once ingested.
  2. Direct Compression: It’s suitable for direct compression tableting processes, which are more straightforward and cost-effective than wet granulation processes.
  3. Physical Stability: MCC helps in maintaining the physical stability of tablets, preventing capping or lamination.
  4. Natural Origin: Derived from wood pulp, MCC is considered a natural ingredient, which may be preferable for certain consumer demographics.


  1. Limited Lubrication: MCC doesn’t offer as effective lubrication properties as magnesium stearate, so it might require the addition of another lubricant in some formulations.
  2. Cost: MCC can be more expensive than some other excipients or fillers.

Magnesium Stearate


  1. Excellent Lubricant: Magnesium stearate is primarily used as a lubricant in tablet formulations. This means it reduces the friction during the tableting process, ensuring that tablets don’t stick to the equipment and are ejected smoothly.
  2. Widely Available: It’s a commonly used excipient, so it’s easy to source and available in different grades.
  3. Low Dosage: Only small amounts are needed in formulations, which can make it cost-effective.


  1. Potential Compression Issues: Excessive amounts of magnesium stearate can affect tablet hardness and disintegration time. This is because it forms a water-repellent film around the particles, potentially affecting the tablet’s dissolution profile.
  2. Allergenic Concerns: While rare, some individuals might be allergic to stearates.
  3. Vegetarian/Vegan Concerns: Magnesium stearate can be derived from both plant and animal sources. If the source is animal-based, it might not be suitable for vegetarians or vegans, and this needs to be specified.
  4. Potential Interference with Drug Absorption: There’s some debate about whether magnesium stearate can affect the bioavailability of certain active ingredients in dietary supplements or drugs. While the consensus is that it generally doesn’t pose significant issues, concerns have been raised.

The choice between MCC and magnesium stearate, or a combination of the two, depends on the specific requirements of the formulation. MCC is more multifunctional, acting as a binder, disintegrant, and aiding in flow, while magnesium stearate is primarily a lubricant. Often, they are used together in a formulation to capitalize on the strengths of each.

At CanXida we are always exploring new ways to improve our formula and MCC is on our for alternative to MS that we are currently exploring.