Capsule Types

Material selection is one of the earliest and most consequential decisions in capsule formulation. Whether you are working with a pharmaceutical grade fill, a moisture-sensitive nutraceutical blend, or an oxygen-labile probiotic stack, the capsule shell material directly affects stability, dissolution behavior, label claims, and retail channel eligibility. 

Choosing the right empty capsule supplier means more than negotiating price per unit: it means getting the material specification right for your product from day one.

This guide covers the three primary hard capsule materials; gelatin, HPMC, and pullulan with technical trade-offs, formulation implications, and sourcing criteria for each.

The Three Materials: What Each One Is

Gelatin is derived from bovine or porcine collagen and has the longest track record in hard capsule manufacturing. It is the lowest-cost option, familiar to all filling equipment types, and widely accepted by global regulatory bodies.

HPMC (hydroxypropyl methylcellulose) is plant-derived and has become the standard vegetarian alternative. It offers better moisture resistance than gelatin, lower cross-linking risk, and broad compatibility with hygroscopic actives. It carries Vegan Society, Kosher, and Halal certifications.

Pullulan is a polysaccharide produced by fermentation from starch. It is also plant-derived and distinguished primarily by its oxygen barrier properties, which are substantially stronger than either gelatin or HPMC. It is the preferred material for oxidation-sensitive formulations.

Gelatin vs HPMC vs Pullulan: Material Comparison

The table below summarizes the key attributes for pharmaceutical and supplement formulation decisions.

Gelatin vs Vegetarian Empty Capsules for Supplements

When Gelatin Is the Right Call

Gelatin capsules remain the appropriate specification for cost-sensitive, fast-release products where the fill is not hygroscopic and the label strategy does not require vegetarian, vegan, Kosher, or Halal positioning. Dissolution is typically fastest with gelatin — an advantage for actives that require rapid gastric release.

For standard vitamin blends, amino acids, and non-hygroscopic powders where clean-label certifications are not a commercial requirement, gelatin is the straightforward choice. Capsuline supplies gelatin capsules in sizes 000 through 5, available in clear and a range of standard colors.

When to Specify HPMC or Pullulan Instead

The shift to HPMC is driven by three formulation and commercial factors. First, HPMC has lower moisture permeability than gelatin, making it the better choice for hygroscopic actives including zinc salts, herbal extracts, and some mineral forms. Second, HPMC does not cross-link under adverse storage conditions — a well-documented gelatin failure mode that slows dissolution in warm or humid markets. Third, HPMC's certification profile (Vegan, Kosher, Halal, Non-GMO) expands retail channel eligibility and label positioning without changing the fill formulation.

Pullulan is the specification when oxidation is the primary degradation pathway. Its oxygen transmission rate is substantially lower than both gelatin and HPMC, which directly supports potency retention at end of shelf life for oxygen-sensitive actives.

Pharmaceutical Grade HPMC Empty Capsules Supplier USA

For R&D and formulation teams sourcing pharmaceutical grade HPMC capsules in the US market, the baseline requirements are cGMP manufacturing, lot-level certificates of analysis, and documented dimensional consistency for filling line compatibility. HPMC capsules disintegrate across a wider pH range than gelatin and within approximately 10 to 30 minutes, supporting consistent absorption behavior across gastrointestinal conditions.

HPMC is the standard capsule material for hygroscopic fills — including zinc, magnesium, calcium, and potassium salts — and for herbal extract powders that absorb moisture during storage. It is also the default specification for products targeting natural, vegan, or functional food retail channels that require clean-label credentials at the capsule level.

Vegetarian HPMC capsule options: capsuline.com/pages/vegetarian-empty-capsules. Available in sizes 000 through 5, including TiO2-free colored variants.

Pullulan Empty Capsules for High-End Supplements

Pullulan's oxygen barrier performance is the primary reason to specify it. Active categories where pullulan is commonly used include:

• Probiotics — where viable cell count at end of shelf life is the label claim
  
• Antioxidants — CoQ10, resveratrol, astaxanthin, and other oxidation-prone actives
  
• Omega-3 dry powder formulations — where rancidity from oxidation is the key stability risk
  
• Any active with documented sensitivity to oxygen exposure

Pullulan is plant-derived, Vegan, Kosher, and Halal certified. The per-unit cost is the highest of the three materials. For oxygen-sensitive formulations where potency at product expiry is a label claim or a regulatory commitment, that cost premium is justified by reduced active degradation and more accurate end-of-shelf-life assay results.
Pullulan capsule options: capsuline.com/collections/pullulan-empty-capsules

Bulk Empty Capsule Supplier for Nutra Products: What to Require

Formulation and procurement teams qualifying a bulk empty capsule supplier for nutraceutical or pharmaceutical manufacturing should request the following documentation as a baseline:

TiO2-free capsules are increasingly required by natural channel retailers, particularly following the EU ban on titanium dioxide (E171) in food and supplement applications in 2022. US natural retailers are expanding similar requirements. Building TiO2-free into the capsule specification at launch avoids a reformulation and re-registration process downstream. Capsuline's gelatin and vegetarian HPMC capsule lines include TiO2-free options.

For larger orders, Capsuline ships in bulk boxes and offers direct guidance from a sales advisor on volume pricing, lead times, and supply terms.

Where to Buy Empty Capsules for Pharmaceutical Manufacturing

Capsuline supplies gelatin, HPMC, and pullulan empty capsules to pharmaceutical manufacturers, contract packagers, compounding pharmacies, and supplement brands in the US and internationally. All materials are available in pharmaceutical grade with cGMP certification, full lot-level documentation, and certifications for Vegan, Kosher, Halal, Non-GMO, and TiO2-free where applicable.

Capsule sizes range from 000 through 5 across all three material types. Standard and colored variants are available for gelatin and HPMC, including TiO2-free colored capsules for brands requiring clean-label color options.

For high-volume sourcing or formulation-specific guidance, contact a Capsuline sales advisor at capsuline.com/pages/contact-us.

Which Material Is Right for Your Project?

The decision maps directly to formulation requirements:

Material selection should be finalized before the fill formulation is locked — not after. The shell material affects not only stability and dissolution, but also the certifications available on the finished label, the retail channels you can enter, and the documentation you can provide to customers and auditors. Start with the formulation constraints, then select the material that meets them.

Sources

1. Capsule material comparison data: industry pharmacopeial references and supplier technical documentation.

2. EU Commission Regulation (EU) 2022/63 — titanium dioxide (E171) ban in food and supplement applications, effective August 2022.

3. Pullulan oxygen barrier performance: comparative oxygen transmission rate data from capsule material technical literature.

4. HPMC dissolution and cross-linking behavior: pharmacopeial dissolution testing literature and comparative capsule stability studies.

This article is for informational purposes only and does not constitute medical advice. These products are not intended to diagnose, treat, cure, or prevent any disease.