Quick answer: HPMC and gelatin describe what a capsule shell is made from. “Delayed release” describes when the contents are designed to be released. These terms describe different things, so an HPMC capsule is not automatically delayed release, and a delayed-release capsule is not automatically vegan.
HPMC, gelatin and delayed release at a glance
| Term | What it describes | What to check |
|---|---|---|
| HPMC (hypromellose) | A cellulose-based capsule shell, commonly chosen for plant-based products. | Confirm the product’s label and full ingredients. |
| Gelatin | A protein capsule shell made from collagen; the animal source can vary by supplier. | Check whether the source meets your dietary or religious requirements. |
| Delayed release | A release design that holds contents back for a period or until specified conditions are met. | Check the tested release specification; the term does not identify the shell material. |
What does HPMC mean?
HPMC stands for hydroxypropyl methylcellulose, also called hypromellose. Capsule makers use it as a plant-derived alternative to gelatin. A particular HPMC product may suit vegetarian or vegan preferences, but always check the finished capsule’s label and ingredients rather than relying on the acronym alone. Some HPMC shells are designed for ordinary release, while specialist HPMC shells can be made for delayed release too. ACG’s capsule range shows that one shell material can be offered in different designs.
See our Empty Vegetarian Vegan Capsule Size 0 listing for the plant-based option in our shop.
What does gelatin mean?
Gelatin is a protein obtained from collagen. Capsule gelatin can come from different animal sources, so the word “gelatin” alone may not tell you whether a product meets a particular dietary requirement. Look for the supplier’s source information if that matters to you. The shell material also does not, by itself, tell you the release profile.
Our shop lists Empty Gelatin Capsule Size 0. Check its product details for the available pack sizes and any source information.
What does delayed release mean?
Delayed release describes timing, not a material. FDA’s ICH Q6A guidance defines it as release at a time other than immediately after oral administration. An enteric design typically aims to resist the acidic environment of the stomach before releasing its contents, but performance depends on the finished product and its testing. Delayed release is also different from extended or sustained release: delaying the start does not necessarily mean that contents are released slowly over many hours.
Our Empty Delayed Release Capsules Size 0 and Size 1 listings describe the capsules as enteric-coated and delayed-release. They do not identify the shell as HPMC or gelatin, so check the product specification if shell material is important to you.
How to choose
Use this quick checklist before choosing an empty capsule:
- If you need a plant-based option, look for a product explicitly labeled vegetarian or vegan and check its ingredient information.
- If choosing gelatin, check the source when dietary or religious requirements apply.
- If you need delayed release, read the product’s tested release specifications. Capsule size and shell material do not tell you the release profile.
- For powders, compare fill capacity and density. Follow the product’s size guidance instead of assuming every powder weighs the same in a capsule.
Match the shell and release profile to the finished product’s specifications.
Frequently asked questions
Are all HPMC capsules delayed release?
No. HPMC names a shell material. Delayed release requires a particular design and tested performance.
Are all delayed-release capsules vegan?
No. Delayed release describes timing; it does not state whether the shell uses HPMC, gelatin or another material.
Further reading
- FDA/ICH Q6A guidance — terminology for immediate, delayed and modified release.
- ACG vegetarian capsule overview — examples of HPMC capsule designs.