Exploring the Materials: What are edible capsules made of?

October 12, 2025 •

3 min read

With an estimated 80% of capsules produced globally being made from gelatin, it's clear this is the industry standard. But for many, the question, "What are edible capsules made of?" is crucial for dietary, ethical, or stability reasons. The answer encompasses both animal and plant-derived materials, each with unique properties and applications.

Quick Summary

Edible capsules are primarily made from animal-derived gelatin or plant-based materials like HPMC and pullulan. Shell composition varies depending on the capsule type (hard or soft) and manufacturer, often including additives for flexibility, color, and stability.

Key Points

Gelatin is the traditional base: Most edible capsules are made from gelatin, a protein derived from animal collagen from sources like cows and pigs.
Plant-based options are widely available: For vegetarian, vegan, or religious diets, alternatives like HPMC (from vegetable cellulose) and pullulan (from fermented starch) are common.
Hard and soft capsules have different compositions: Hard-shell capsules contain powdered ingredients and are made from gelatin, HPMC, or pullulan, while softgels enclose liquids and use a more flexible gelatin or tapioca-based shell.
Additives improve performance: Plasticizers like glycerin are used in softgels for flexibility, while opacifiers and colorants enhance visual appeal and protect contents from light.
Enteric coatings control release: Specialized coatings are applied to some capsules to prevent them from dissolving in the stomach, ensuring the contents are released in the intestines.
Material choice impacts stability: The material affects the capsule's moisture sensitivity and oxygen permeability, influencing shelf life and compatibility with specific ingredients.

What are Edible Capsules Made of? Primary Materials

The composition of an edible capsule depends largely on the intended use and the dietary preferences of the consumer. While gelatin has been the standard for decades due to its low cost and reliability, plant-based alternatives have gained popularity.

Gelatin: The Traditional Choice

Gelatin is a translucent, tasteless, and odorless solid substance derived from the partial hydrolysis of collagen. This protein is sourced from animal skin, bones, and connective tissues, commonly from cows and pigs. Gelatin is water-soluble, forming a gel when cooled and melting at body temperature for quick dissolution. It is used for both hard-shell and softgel capsules. However, its animal origin makes it unsuitable for certain diets, and its moisture content can lead to brittleness or tackiness in varying humidity. Fish gelatin is also used for specific dietary needs.

Plant-Based Alternatives: The Rise of Vegetarian Capsules

Vegetarian and vegan capsules offer non-animal options, typically derived from plant-based polysaccharides.

Common Plant-Based Materials:

Hydroxypropyl Methylcellulose (HPMC): A cellulose derivative from plants like pine or poplar. HPMC capsules have low moisture content, making them suitable for moisture-sensitive ingredients and offering stability in varying humidity. They can also be used for delayed-release formulations.
Pullulan: A water-soluble polysaccharide produced by the fermentation of starch. It provides an excellent oxygen barrier and dissolves quickly.
Tapioca Starch: Derived from the cassava root and used for vegan softgel capsules.
Carrageenan: Extracted from red seaweed and sometimes used with other plant materials in capsule shells.

Beyond the Core: Additives and Specialized Coatings

Additional ingredients are included in capsules to improve their function, appearance, and stability.

Plasticizers: Added to softgel capsules for flexibility, such as glycerin and sorbitol.
Colorants and Opacifiers: Provide color or opacity for identification and protection of light-sensitive ingredients.
Preservatives: Sometimes used in softgels to prevent microbial growth.
Specialized Coatings (e.g., Enteric Coatings): These polymer-based coatings allow capsules to bypass the stomach and dissolve in the small intestine, useful for sensitive or irritating ingredients.

Hard vs. Soft Capsules: Shell Composition and Function

Edible capsules come as either hard-shelled or soft-shelled. Hard-shelled capsules have two halves filled with dry ingredients. Soft-shelled capsules (softgels) are a single unit, often containing liquids, and are made with plasticizers for flexibility. Both gelatin and plant-based materials are used for hard capsules, while softgels typically use gelatin or tapioca starch.

Comparison of Capsule Shell Materials


Feature	Gelatin (Animal-Derived)	HPMC (Plant-Derived)	Pullulan (Plant-Derived)
Source	Animal collagen (bovine, porcine, fish)	Vegetable cellulose (wood pulp)	Fermented tapioca or corn starch
Cost	Generally lower cost	More expensive than gelatin	Can be more expensive than HPMC
Suitability	Not suitable for vegan, vegetarian, or certain religious diets	Ideal for vegan, vegetarian, kosher, and halal diets	Ideal for vegan, vegetarian, kosher, and halal diets
Moisture Content	Higher moisture content (12-16%), susceptible to brittleness or stickiness	Low moisture content, stable in varying humidity	Low moisture content, good stability
Oxygen Barrier	Standard barrier properties	Standard barrier properties, improved barrier compared to gelatin is possible	Superior oxygen barrier, best for oxidation-sensitive ingredients
Dissolution	Dissolves quickly in the stomach	Can be used for delayed-release formulations	Dissolves quickly in the stomach
Best for	Powders and liquids (softgels)	Powders, granules, sensitive ingredients	Highly oxidation-sensitive ingredients

Conclusion

Edible capsules utilize materials like gelatin, HPMC, and pullulan, with gelatin being the traditional choice and plant-based options growing in popularity due to dietary needs and improved stability. The material selection for hard or soft capsules considers cost, ingredient compatibility, and consumer requirements. Additives and specialized coatings further customize capsule function, ensuring effective drug delivery. The development of new edible polymers continues to expand available options for manufacturers and consumers.

For additional information on the science behind capsules, consult relevant pharmacological resources like articles found on the National Institutes of Health website.(https://pmc.ncbi.nlm.nih.gov/articles/PMC5830853/)

Frequently Asked Questions

No, edible capsules are not made of petroleum-based plastic. They are made from edible, biodegradable polymers like gelatin or plant cellulose that are designed to dissolve harmlessly in the body.

Hard-shell capsules consist of two filled halves joined together and contain dry powders or pellets. Softgel capsules are a single, sealed unit containing liquid or semi-solid ingredients, and their shell is more flexible due to added plasticizers.

HPMC is Hydroxypropyl Methylcellulose, a common plant-based material for vegetarian capsules. It is derived from vegetable cellulose, often sourced from pine or poplar trees.

Vegetarian capsules (HPMC, pullulan) are made from plant-based materials, making them suitable for vegan, vegetarian, and religious diets. They generally have lower moisture content and better stability in varying humidity compared to gelatin capsules.

Enteric-coated capsules have a special coating that resists stomach acid, allowing the capsule to pass through the stomach and dissolve in the small intestine. This is often used for medications that irritate the stomach or are sensitive to stomach acid.

A standard gelatin capsule typically dissolves in the stomach within 20 to 30 minutes, releasing its contents. Plant-based capsules like HPMC may take slightly longer, while enteric-coated capsules are designed for delayed release in the intestine.

Colorants are added to capsules for brand identification, to help patients distinguish between different medications, and to make the capsules opaque to protect light-sensitive ingredients.