Types of gelatin capsules: hard versus soft – detailed comparison and applications

Gelatin capsules are a popular alternative to tablets for the oral administration of medications and dietary supplements. In this article, we present the key differences between hard and soft gelatin capsules. We also answer the question of whether gelatin capsules are suitable for vegetarians or vegans.

Introduction: What are gelatin capsules and why are they so popular?

Gelatin capsules are made from natural animal-derived collagen (most often pork or beef). Their popularity as a dosage form results from the fact that:

• gelatin capsules dissolve well, ensuring rapid release of the active substance;
• gelatin capsules come in standard sizes, making them easy to fill on an industrial scale;
• empty gelatin capsules can easily encapsulate various forms of medicines – from powders to micropellets;
• gelatin is inexpensive and readily available.

Gelatin capsules are divided into hard gelatin capsules and soft gelatin capsules (commonly referred to as softgels).

Hard gelatin capsules – structure, filling, and applications

Hard gelatin capsules consist of two cylindrical parts: a body and a cap, which fit tightly together. Empty hard gelatin capsules are filled with powders, microcapsules, granules, or pellets. They are used in over-the-counter medicinal products, such as vitamins, probiotics, and herbs. They are also used in prescription drugs that require mixing multiple components in a single capsule.

Soft gelatin capsules (softgels) – characteristics, materials, and uses

Hard and soft gelatin capsules primarily differ in their structure, filling method, and usage. For hard gelatin capsules, the manufacturing process is two-step – first the empty gelatin shell is created, then it is filled with the active substance. This process is technologically simple and cost-effective.

Soft gelatin capsules have a one-piece, flexible form and are produced in a single step using rotary die machines. The manufacturing process involves forming and filling the capsules in one continuous operation using rotating dies and molds, which results in a higher cost.

Hard gelatin capsules are more versatile, making them a popular choice among pharmaceutical and supplement manufacturers. They are ideal when the active substance is in dry form or when the final product contains multiple ingredients.

Soft gelatin capsules offer more flexibility for liquid forms of medication and visual appeal. They are often transparent or semi-transparent, giving them a consumer-friendly appearance. They are used when the active substance is in liquid, semi-solid, or oily form. This capsule type is also suitable for:

• oxidation-sensitive drugs;
• extended-release formulations;
• fat-soluble substances;
• substances that require rapid release in the gastrointestinal tract.

To learn more, see: Gelatin capsules – applications, types, and production

Advantages and limitations of gelatin capsules

Gelatin used in capsule production is widely available and has good solubility. Unfortunately, this protein also has certain limitations, such as:

• it is sensitive to moisture, increasing the risk of degradation of sensitive active ingredients and microbial growth;
• it may interact with some active ingredients used in medicinal products;
• it is not acceptable for vegetarians and vegans.

Good to know: Gelatin capsules are completely safe. In rare cases, individuals with multiple food allergies may experience allergic reactions after using gelatin capsules.

Plant-based alternatives to gelatin capsules

Pharmaceutical and supplement manufacturers are increasingly looking for plant-based alternatives to gelatin capsules. A plant-based substitute for gelatin capsules can be hydroxypropyl methylcellulose (HPMC), a cellulose derivative. This semi-synthetic polymer offers excellent chemical and physical stability and can be used in formulations that require special storage conditions.

Other plant-based alternatives to gelatin capsules include:

• Pullulan – a polysaccharide produced by fermentation using Aureobasidium pullulans fungi;
• CMC (sodium carboxymethyl cellulose) – a synthetic cellulose derivative;
• Modified starch – natural starch (e.g., corn) processed to change its properties.

In recent years, encapsulation technology has developed rapidly. Gaining popularity are not only plant-based alternatives to gelatin capsules but also:

• capsules with modified release – e.g., enteric-coated;
• capsules made using Liquid-Fill Hard Capsule (LFHC) technology, which allows liquids to be enclosed in hard capsules;
• microcapsules that protect active ingredients and enable targeted release.

New trends in the pharmaceutical and supplement industries arise not only from changing consumer expectations but also from new regulations (e.g., the EU ban on titanium dioxide (TiO₂) in food production). In the face of such dynamic changes, choosing the right supplier of pharmaceutical raw materials and capsules and tablets is more important than ever. Only trusted partners who follow technological trends, regulatory requirements, and have experience in contract manufacturing of dietary supplements and medications can ensure product safety, high quality, and innovation.

Gelatin Capsules – Frequently Asked Questions

I. What is the main difference between hard and soft gelatin capsules?

Hard gelatin capsules are two-piece and contain powdered or granulated medication. Soft gelatin capsules are one-piece and contain medication in liquid or semi-liquid form. 

II. Why are soft capsules more commonly used for oils and extracts?

Soft gelatin capsules protect liquid drugs from oxidation and allow for easy dosing.

III. Can hard capsules contain liquid?

Only specially designed hard capsules for liquids (e.g., made using Liquid-Fill technology) are suitable for filling with liquid medications.

IV. Are gelatin capsules suitable for vegetarians or vegans?

No, traditional gelatin capsules contain animal-derived ingredients. However, plant-based alternatives such as hydroxypropyl methylcellulose (HPMC) or pullulan are available.

V. Can gelatin cause allergic reactions?

In rare cases, individuals with multiple food allergies may experience allergic reactions after using gelatin capsules.

VI. How should gelatin capsules be stored to maintain their properties?

Gelatin capsules should be stored in a dry, cool place, away from light and moisture, preferably in a tightly closed container.

References

1. European Pharmaceutical Review (2023). Capsule formulation: future trends [online] Available at: https://www.europeanpharmaceuticalreview.com/article/184060/capsule-formulation-future-trends [online access: 20.05.2025]
2. Gullapalli, R.P. and Mazzitelli, C.L. (2017). Gelatin and Non-Gelatin Capsule Dosage Forms. Journal of Pharmaceutical Sciences, 106(6), 1453–1465. https://doi.org/10.1016/j.xphs.2017.02.006.
3. Land, M.H., Piehl, M.D., Burks, A.W. (2013). Near fatal anaphylaxis from orally administered gelatin capsule. The Journal of Allergy and Clinical Immunology: In Practice, 1(1), 99–100. https://doi.org/10.1016/j.jaip.2012.09.004. 
4. Prakash, A., Soni, H., Mishra, A., Sarma, P. (2017). Are your capsules vegetarian or nonvegetarian: An ethical and scientific justification. Indian Journal of Pharmacology, 49(5), 401–404. https://doi.org/10.4103/ijp.IJP_409_17. 
5. Vitamin Manufacture (2020). What is an HPMC Capsule? [online]. Available at: https://www.vitaminmanufacture.co.uk/2020/10/what-is-an-hpmc-capsule [online access: 20.05.2025]