For the health and pharmaceutical products industry, the answer to what is the most widely used capsule size is Size 0. Capsule 0 measures 0.68 mL (7.64 mm in diameter, 21.7 mm in length) under USP standards, with a global market share of 42% (Grand View Research, 2023 data). Its wide utility is due to its synergistic load capacity (300-600 mg, varying with density of material 0.4-1.2 g/cm³) and patient ease of swallowing (diameter ≤8 mm capsules are 60% easier to swallow). For example, Pfizer’s lipid-lowering drug atorvastatin calcium tablets use gelatin capsule No. 0, filled with one capsule filling of 500 mg±3%, with an annual output of more than 5 billion capsules occupying 35% of its total solid preparation capacity.
From the economic cost and efficiency of manufacture perspective, the most popular capsule size directly impacts enterprise revenues. The procurement cost of gelatin capsule 0 is US $0.015-0.025 / capsule (HPMC vegetarian capsule is US $0.03-0.04 / capsule), and its suitable automatic filling machine (such as Bosch GKF 7200) can generate 150,000 / hour efficiency, and the time for changing the mold is only 8 minutes (previous model is 20 minutes). The cost of production per individual grain is reduced to $0.008 ($0.012 for semi-automatic devices). Indian pharmaceutical company Cipla via bulk purchasing of No.0 capsule (yearly procurement of 12 billion capsules), price of a unit capsule was trimmed to $0.011 and the gross margin was increased to 68%.
Market demand and regulations further establish No. 0’s leading position. The European Medicines Agency (EMA) requires children’s capsules to have a diameter ≤8 mm (0 meets this), and the FDA length limit on sustained-release forms (≤25 mm) is also compatible with capsule 0 (21.7mm). HPMC capsule No. 0 (from Catalent) was selected by Moderna in 2021 to fill CoVID vaccine excipients because its expansion ratio was only 0.5% (1.2% for gelatin capsules) after the 40℃/75%RH acceleration test, and the dissolution test was passed (≥85% release after 30 minutes). Additionally, capsule 0 is utilized 55% in the health products category (e.g., American product Nature Made’s fish oil capsule), and its capacity is suitable for 500 mg EPA+DHA blend (filling density 0.9 g/cm³).
the influence of future trends on what is the most common capsule size cannot be neglected either. The innovation in plant capsules (e.g., HPMC) has encouraged optimizing size 0: Vegicaps 0 from Capsugel, Switzerland, optimizes the drug load to 650 mg (±2% tolerance) by optimizing the wall thickness (0.08 mm compared to 0.10 mm gelatin), and reducing raw material consumption by 10%. The need for tailored medicine bred the miniaturization trend – Capsule 0 can be launched in phases with laser drilling technology (for example, gastric and enteric double coating of the anti-cancer medication paclitaxel), and its research cost is 40% lower than tailored size (for example, No. 5).
Variations by regions reflect market forces. In the Asia-Pacific region, capsule 0 holds 60% of the gelatin Market (in China’s medical insurance fee control policy, generic drugs prefer cost-effective specifications), whereas in the European and American market take into account food trend, the year-on-year demand for HPMC capsule 0 increased by 25% (Transparency Market Research data). For example, Blackmores in Australia uses the No. 0 vegetarian capsule for its vitamin D3 product (1000 IU per capsule), and the terminal price is 20% higher than that of the gelatin capsule, but consumers pay 30% more.
Overall, the most common capsule size is determined according to technical requirements (0.68 mL±5% volume), cost-effectiveness (ROI≤18 months), and regulatory adherence (90% pharmacopoeia compatibility worldwide). As the global plant capsule market is estimated to be worth over $1.5 billion (16% CAGR) by 2025, Size 0 will continue to dominate due to its technological expandability (e.g., AI-optimized filling) and supply chain maturity.