Understanding Empty Capsules Size 00: Standards, Properties, and Applications

Different Types of Size 00 Empty Capsules

A size 00 empty capsule is one of the most widely used capsule sizes in the pharmaceutical, nutraceutical, and herbal supplement industries. Known for its generous fill capacity—typically holding between 500 to 1,000 milligrams depending on the substance—it offers versatility for both solid powders and liquid formulations. These capsules are essential for custom compounding, private-label supplements, and research applications, allowing for precise dosing and easy encapsulation.

The popularity of size 00 stems from its balance of size and usability—it's large enough to hold effective doses without being overly bulky for swallowing. Below is a detailed breakdown of the most common types of size 00 empty capsules, their composition, benefits, and ideal applications.

Gelatin Capsules

Made from animal-derived collagen, typically sourced from bovine or porcine origins, these are the traditional standard in capsule manufacturing.

Advantages

• Excellent solubility and rapid dissolution in the stomach
• Smooth texture and easy to swallow
• Cost-effective and widely available
• Compatible with both powders and semi-liquids

Limitations

• Not suitable for vegetarians, vegans, or certain religious diets
• Sensitive to moisture and high humidity
• Potential for cross-contamination in allergen-sensitive environments

Best for: General health supplements, pharmaceuticals, non-vegetarian formulations

Vegetarian Capsules (HPMC / Pullulan)

Formulated from plant-based polymers like hydroxypropyl methylcellulose (HPMC) or pullulan, these capsules are ideal for vegan and vegetarian markets.

Advantages

• Fully vegetarian and vegan-friendly
• Stable in a wide range of temperatures and humidity levels
• Excellent clarity and aesthetic appeal
• Preferred for herbal, organic, and clean-label products

Limitations

• Slightly higher cost than gelatin capsules
• May dissolve more slowly in some cases
• Limited flexibility compared to gelatin

Best for: Vegan supplements, herbal products, religious or dietary-restricted consumers

Gel Capsules (Softgels)

Soft, sealed capsules made from gelatin or plant-based alternatives, specifically designed to encapsulate liquids, oils, and fat-soluble compounds.

Advantages

• Enhanced bioavailability of oil-based ingredients (e.g., fish oil, CBD, vitamins A, D, E, K)
• Hermetically sealed to prevent oxidation and leakage
• Smooth texture and easy to swallow
• Ideal for taste-masking unpleasant flavors

Limitations

• Not suitable for dry powders or granules
• More complex and expensive to manufacture
• Require specialized filling equipment

Best for: Omega-3s, essential oils, liquid vitamins, and fat-soluble nutrients

Alginate (Seaweed-Based) Capsules

Derived from brown seaweed, these capsules use sodium alginate, which forms a gel when exposed to calcium, enabling unique delivery mechanisms.

Advantages

• 100% natural and biodegradable
• Capable of forming microcapsules for controlled or delayed release
• Excellent for encapsulating probiotics and sensitive actives
• Vegan and sustainable sourcing

Limitations

• Limited availability and higher cost
• Requires specific chemical conditions for gelation
• Less common in mainstream consumer products

Best for: Research applications, probiotic delivery, functional foods, and advanced drug delivery systems

Cellulose Capsules

Typically made from HPMC or methylcellulose, cellulose-based capsules are a subset of vegetarian capsules with enhanced moisture resistance.

Advantages

• Superior moisture barrier properties
• Stable in high-humidity environments
• Fast-dissolving in gastric fluid
• Non-animal, non-GMO, and kosher/halal compliant options available

Limitations

• Can be brittle if not stored properly
• Slightly more expensive than gelatin
• Limited elasticity compared to softgels

Best for: Moisture-sensitive formulations, tropical climates, long-shelf-life products

Expert Tip: When choosing between capsule types, consider not only the formulation (powder vs. liquid) but also your target market’s dietary preferences. For commercial products, clearly labeling capsules as "vegan," "halal," or "non-GMO" can significantly enhance consumer trust and marketability.

What Makes Size 00 Empty Capsules Different from Size 0?

While both size 0 and size 00 empty capsules serve similar purposes in dietary, herbal, and pharmaceutical applications, they are not interchangeable due to key differences in physical dimensions, capacity, and usage. Understanding these distinctions is essential for proper formulation, dosing accuracy, and manufacturing efficiency.

Cap and Body Length & Diameter

The most noticeable difference between size 0 and size 00 capsules lies in their physical dimensions. Contrary to what the numbering might suggest, size 00 capsules are actually larger than size 0 — not smaller. This can be confusing, as a higher number typically implies a smaller size in many systems, but with gelatin and HPMC capsules, the reverse is true: the more zeros, the larger the capsule.

Size 00 Capsule

• Length: Approximately 0.937 inches (23.8 mm)
• Diameter: Approximately 0.70 inches (17.3 mm)
• Slightly shorter but wider than size 0

Size 0 Capsule

• Length: Approximately 0.846 inches (21.5 mm)
• Diameter: Approximately 0.63 inches (16.0 mm)
• Narrower and slightly shorter than size 00

Correction Note: The original statement that "size 00 capsules have a smaller diameter than size 0" is incorrect. In fact, size 00 capsules have a larger diameter (17.3 mm vs. 16.0 mm), making them wider and capable of holding more material despite being only slightly longer.

Volume and Capacity

Capacity is one of the most critical factors when selecting a capsule size, especially for precise dosing in supplements or medications.

As shown, size 00 capsules offer nearly 50% greater volumetric capacity than size 0, allowing them to hold significantly more powder, granules, or even small pellets. This makes them ideal for high-dose formulations where multiple ingredients must be combined in a single unit.

Filling Compatibility

The internal volume and diameter directly influence the types of materials each capsule can accommodate effectively.

Size 0 – Best for Fine Powders

Ideal for finely ground powders, microcrystalline substances, or low-dose active ingredients. Due to their narrower bore, size 0 capsules may struggle with coarse granules or fibrous herbal materials that could cause bridging or incomplete filling.

Size 00 – Handles Bulkier Fillings

The wider body of size 00 capsules allows for easier flow of coarser powders, herbal blends, probiotics, or even small beads and granules. They are less prone to clogging during automated or manual filling processes, especially with bulky or low-density materials.

Common Applications

Both capsule sizes are widely used across the nutraceutical and pharmaceutical industries, but their applications differ based on dosage requirements and formulation complexity.

Important: Always verify capsule dimensions and fill weights during product development. Using the wrong capsule size can lead to under-dosing, overfilling, machine jamming, or patient non-compliance. Conduct flow tests and stability studies when switching between size 0 and size 00 to ensure consistent performance and regulatory compliance.

Important Features For Size 00 Empty Capsules

When purchasing size 00 empty capsules in bulk, it's essential to evaluate their quality to ensure optimal performance, safety, and consumer satisfaction. The quality of capsules directly influences their functionality, shelf life, and end-user experience. Size 00 capsules are among the most widely used in the supplement and pharmaceutical industries due to their ideal capacity and compatibility with automated filling systems. Below are the key features that define high-quality size 00 empty capsules.

Material Quality and Purity

High-grade size 00 capsules are manufactured using premium materials such as pharmaceutical-grade gelatin, hydroxypropyl methylcellulose (HPMC), or Pullulan. Each material offers unique benefits:

• Gelatin: Derived from animal collagen, it provides excellent elasticity and is ideal for moisture-sensitive formulations
• HPMC: A plant-based alternative perfect for vegetarian and vegan products, with strong resistance to humidity
• Pullulan: A natural, non-GMO polysaccharide offering superior clarity and low moisture content, ideal for premium supplements

Key consideration: Ensure capsules meet USP, EP, or FDA standards for purity and safety, especially for ingestible products.

Moisture and Oxygen Barrier

Protecting the active ingredients from environmental degradation is critical. High-quality size 00 capsules provide effective barriers against moisture and oxygen, preserving the potency and shelf life of encapsulated substances.

• Low moisture permeability prevents clumping, degradation, or microbial growth in hygroscopic powders
• Oxygen resistance helps maintain the efficacy of sensitive compounds like omega-3s, probiotics, and antioxidants
• Advanced coatings or multi-layer designs enhance barrier performance in challenging storage conditions

Pro tip: For long-term storage or humid climates, consider HPMC or Pullulan capsules, which offer better moisture resistance than standard gelatin.

Easy to Fill and Seal

The design of size 00 capsules is optimized for both manual and automated filling processes. A smooth interior and precise cap-to-body fit ensure consistent dosing and reliable sealing.

• Uniform internal diameter allows for efficient powder flow and reduces bridging during filling
• Tight tolerance manufacturing ensures a secure snap-fit seal without the need for additional adhesives
• Vegetarian capsules often feature enhanced lubricity for seamless machine processing

Critical factor: Poorly fitting capsules can lead to leakage, inconsistent dosing, or production delays in commercial settings.

Pill Splitter Compatibility

Some size 00 capsules are designed with score lines or alignment grooves to allow for easy splitting—ideal for dose customization.

• Scored capsules enable users to divide contents precisely, beneficial for titration or pediatric dosing
• Not all capsules are suitable for splitting; un-scored versions may crack unevenly or spill contents
• Best suited for powders or granules rather than liquids or oils

Smart choice: Recommend split-capable capsules for healthcare providers or patients requiring flexible dosing regimens.

Printable Surface

A smooth, uniform surface allows for clear labeling and branding directly on the capsule shell—enhancing both functionality and market appeal.

• Laser printing or food-grade inks can be used to mark dosage strength, product codes, or brand logos
• High-clarity capsules (especially Pullulan) offer excellent visibility for printed information
• Custom printing supports product differentiation and counterfeit protection

Marketing advantage: Branded or color-coded capsules improve shelf presence and consumer recognition.

Stability Under Various Conditions

Top-tier size 00 capsules maintain structural integrity across a range of temperatures and humidity levels, making them suitable for global distribution and diverse storage environments.

• Resistant to brittleness in dry climates and softening in humid conditions
• Suitable for encapsulating sensitive ingredients like herbal extracts, essential oils, and probiotics
• Stable performance in temperatures ranging from 15°C to 30°C (59°F to 86°F)

Technical note: Store capsules in a cool, dry place with 40–60% relative humidity to maximize shelf life.

Professional Recommendation: When selecting size 00 empty capsules, prioritize material compatibility with your formulation. For example, choose HPMC or Pullulan for moisture-sensitive or vegan products, and gelatin for cost-effective, high-volume applications. Always request sample batches to test fillability, sealing, and stability before large-scale procurement.

Additional Considerations

• Regulatory Compliance: Ensure capsules are manufactured in FDA-registered, GMP-certified facilities to meet quality and traceability standards
• Allergen-Free Options: HPMC and Pullulan are free from common allergens like soy, gluten, and dairy, making them suitable for sensitive populations
• Eco-Friendly Packaging: Choose suppliers offering recyclable or biodegradable bulk packaging to support sustainability goals
• Color and Opacity: Available in clear, opaque, or colored variants for branding, light protection, or aesthetic appeal
• Customization: Many manufacturers offer private labeling, custom printing, and tailored formulations for private-label brands

How To Choose Size 00 Empty Capsules: A Comprehensive Buyer’s Guide

Selecting the right size 00 empty capsules is crucial for manufacturers, supplement formulators, and health product developers. These capsules are among the most popular due to their ideal balance of capacity and ease of swallowing. Beyond basic physical features, several key factors must be evaluated to ensure safety, efficacy, and market competitiveness. This guide outlines the essential considerations when choosing size 00 empty capsules for your product line.

Important Note: Size 00 capsules typically hold between 500–800 mg of powder, depending on density. Always verify fill weight compatibility with your formulation to avoid underfilling or overfilling, which can affect dosage accuracy and capsule integrity.

Quality of Materials

The material used in manufacturing size 00 empty capsules directly impacts product safety, stability, and consumer acceptance. High-quality capsules are made from pharmaceutical-grade raw materials that meet strict purity and performance standards.

• Gelatin (Animal-Derived): Offers excellent strength, clarity, and uniform dissolution. Ideal for most dry formulations but not suitable for vegetarian or vegan markets.
• HPMC (Hydroxypropyl Methylcellulose): A plant-based alternative derived from cellulose. Preferred for vegetarian, vegan, and halal/kosher-certified products. Provides good moisture resistance and consistent disintegration.
• Pullulan: A naturally fermented, water-soluble polysaccharide. Known for superior clarity, low moisture content, and excellent barrier properties. Often used in premium supplements and probiotics.

Choosing the right material ensures compatibility with your active ingredients and aligns with your target market’s dietary preferences and regulatory requirements.

Filling Range and Compatibility

Size 00 capsules offer one of the highest volumetric capacities among standard capsule sizes, making them ideal for formulations requiring larger doses or multiple ingredients per serving.

• Can accommodate bulky herbal powders, fiber blends, or multi-ingredient complexes without requiring multiple capsules.
• Suitable for both fine powders and granular substances, though flowability should be tested during filling.
• Not recommended for liquids or oils unless using specialized sealed capsules or lipid-based fill technologies.

Consider conducting a fill test with your specific formulation to ensure optimal packing density and avoid air pockets or inconsistent dosing.

Capsule Thickness

The wall thickness of a size 00 capsule influences both shelf life and bioavailability:

• Thicker-Walled Capsules: Provide enhanced protection against moisture, oxidation, and mechanical stress. Ideal for sensitive ingredients like probiotics, enzymes, or omega-3s that require extended stability.
• Thinner-Walled Capsules: Dissolve more rapidly in the gastrointestinal tract, leading to faster release and improved bioavailability. Best for fast-acting supplements such as energy boosters or nootropics.

Balancing protection and dissolution speed is key—select thickness based on your product’s release profile and storage conditions.

Custom Printing and Branding Options

In a crowded supplement market, branding starts at the capsule level. Customization enhances product recognition, supports brand identity, and improves consumer trust.

• Available in a wide range of colors to match brand palettes or differentiate product lines.
• Laser printing or food-grade ink options allow for logos, dosage indicators, or batch codes directly on the capsule shell.
• Matte, glossy, or two-tone finishes can create a premium aesthetic and deter counterfeiting.

Investing in branded capsules not only strengthens marketing but also helps prevent confusion among consumers taking multiple supplements.

Regulatory Compliance and Safety Features

Ensuring regulatory compliance is non-negotiable for any capsule-based product entering consumer markets.

• Look for capsules compliant with USP, BP, EP, and FDA standards for pharmaceutical excipients.
• Certifications such as Non-GMO, Kosher, Halal, Vegan, and Gluten-Free expand market accessibility.
• Some suppliers offer tamper-evident or child-resistant capsule designs for added safety, especially important in pharmaceutical or high-dose applications.
• Ensure full traceability of raw materials and manufacturing processes to meet GMP (Good Manufacturing Practice) requirements.

Always request a Certificate of Analysis (CoA) and Material Safety Data Sheet (MSDS) from your supplier to verify compliance.

Supplier Reliability and Supply Chain Consistency

A dependable supplier is essential for maintaining product quality and meeting production timelines.

• Choose manufacturers with a proven track record of consistent capsule quality, batch-to-batch uniformity, and on-time delivery.
• Transparent suppliers provide detailed specifications, including moisture content, disintegration time, and microbiological testing results.
• Assess lead times, minimum order quantities (MOQs), and scalability for future growth.
• Prefer suppliers who offer technical support, sample kits, and customization services tailored to your needs.

Building a long-term relationship with a trusted capsule provider reduces risk and ensures continuity in your production cycle.

Expert Tip: Before finalizing your capsule choice, request physical samples to evaluate appearance, ease of filling, and disintegration time. Conduct accelerated stability testing under various temperature and humidity conditions to ensure long-term performance.

Final Recommendations

• Match capsule material to your product’s formulation and target audience (e.g., vegan customers).
• Verify fill weight and flow characteristics with your specific powder blend.
• Invest in branding to stand out in competitive wellness markets.
• Always prioritize suppliers with full regulatory documentation and quality assurance protocols.
• Consider future scalability when selecting packaging and ordering options.

Making an informed decision when selecting size 00 empty capsules ensures your product delivers consistent dosing, meets safety standards, and resonates with consumers. By evaluating material quality, functionality, compliance, and supplier reliability, you can build a high-quality, market-ready supplement with confidence.

Frequently Asked Questions About Size 00 Empty Capsules

Size 00 empty capsules are among the most popular choices for encapsulating a wide variety of dietary and medicinal substances due to their larger capacity—typically holding between 500 to 1000 milligrams of powder, depending on density. These capsules are ideal for:

• Powdered Supplements: Such as vitamin C, magnesium, spirulina, and probiotics, which are commonly filled into size 00 capsules for accurate dosing and ease of ingestion.
• Herbal Extracts and Concentrates: Including turmeric, ashwagandha, and other plant-based powders that benefit from protection against moisture and oxidation.
• Pharmaceutical Compounds: Custom medications prepared by compounding pharmacies often use size 00 capsules for precise delivery of active ingredients.
• Liquid and Semi-Liquid Fillings: Essential oils, fish oil, CBD oil, and other concentrated extracts can be encapsulated using gelatin-based size 00 capsules, especially when sealed properly to prevent leakage.

It's worth noting that both size "0" and "00" capsules are preferred for higher-dose formulations, with size 00 offering approximately 20–30% more volume than size 0. This makes them particularly suitable for consumers who want fewer capsules per dose, improving compliance and convenience.

Ensuring the quality of size 00 empty capsules is crucial for product safety, stability, and consumer satisfaction. Buyers—whether manufacturers, supplement brands, or home formulators—should consider the following best practices:

• Material Quality: Opt for capsules made from pharmaceutical-grade gelatin (for animal-derived) or hydroxypropyl methylcellulose (HPMC) for vegetarian and vegan options. High-purity materials reduce the risk of contaminants and improve dissolution rates.
• Certifications: Look for third-party certifications such as USP, NSF, Kosher, Halal, or GMP (Good Manufacturing Practices), which verify adherence to strict quality and safety standards.
• Transparency from Suppliers: Reputable manufacturers provide detailed specifications, including moisture content, disintegration time, and compatibility data with various fill materials.
• Stability Testing: Conduct or request compatibility tests to ensure the capsule shell does not react with the filling, especially for acidic, oily, or hygroscopic substances.
• Visual Inspection: High-quality capsules should be uniform in size, color, and texture, with smooth surfaces and tightly sealed bodies and caps—indicative of precision manufacturing.

By prioritizing these factors, buyers can ensure they are sourcing reliable, safe, and effective capsules that meet regulatory and consumer expectations.

Yes, size 00 empty capsules can be used to encapsulate liquids, but success depends heavily on the capsule material and sealing method. Not all capsule types are equally suited for liquid fillings:

To safely encapsulate liquids in size 00 capsules, it’s essential to use a heat sealer or banding tool to hermetically seal the capsule body and cap. Additionally, avoid overfilling and ensure the liquid formulation is compatible with the capsule shell to prevent degradation or premature release. For commercial production, liquid-filling machines with precision nozzles and automatic sealing are recommended.

Size 00 empty capsules significantly contribute to extending the shelf life and maintaining the potency of sensitive formulations through several protective mechanisms:

• Airtight Protection: When properly sealed, capsules create a barrier against oxygen, reducing oxidation of sensitive ingredients like omega-3 fatty acids, vitamins A, C, and E, and herbal extracts.
• Moisture Resistance: High-quality gelatin and HPMC capsules help prevent moisture absorption, which can degrade active ingredients and promote microbial growth.
• Light Blocking: Opaque or colored capsules shield light-sensitive compounds (e.g., CBD, certain enzymes, and probiotics) from UV degradation, preserving efficacy.
• Microbial Barrier: Intact capsules inhibit contamination from bacteria, mold, and environmental pollutants, especially when stored in controlled conditions.
• Controlled Release Options: Enteric-coated size 00 capsules can protect acid-sensitive ingredients, allowing targeted release in the intestines and improving bioavailability.

By encapsulating products in size 00 capsules, manufacturers and formulators can enhance product stability, reduce degradation, and ensure consistent dosing throughout the product’s shelf life. This is particularly beneficial for supplements with naturally short expiration periods or those requiring long-term storage without refrigeration.