Previously, we delved into the core application advantages of HPMC capsules in the vegetarian health supplement sector. As the penetration of plant-based excipients in the global nutrition and health industry continues to rise, the material selection of capsules—the core carrier of end products—has shifted from a simple judgment of "plant-sourced or not" to a refined decision-making process based on physicochemical properties.

Hydroxypropyl Methylcellulose (HPMC) and Pullulan have emerged as the two mainstream solutions for plant-based capsules, yet they exhibit distinct differences in technical parameters and application scenarios. Combining the 2026 market trends and formulation requirements for pharmaceutical production, this analysis clarifies their core application boundaries from three dimensions: stability adaptation, supply chain and brand positioning alignment, and product portfolio strategy, providing actionable selection references for industry peers and brand owners.

1. Selection Logic Based on Filler Properties

The core value of a capsule substrate is to provide a stable protective barrier for the filler. The compatibility between the substrate and the filler directly determines the final quality and shelf-life performance of the product, with clear demarcation in their core applicable scenarios:

For highly hygroscopic fillers such as probiotics, creatine, and certain high-concentration herbal extracts, HPMC capsules offer an irreplaceable advantage. With a low equilibrium water content of 3%-5%—a level far lower than the industry standard of 13%-15% for gelatin capsules and 8%-10% for Pullulan capsules—they effectively block moisture migration between the capsule shell and the filler, fundamentally reducing the risks of caking, deliquescence, and loss of active ingredient potency. This also makes HPMC the preferred substrate for vegetarian health supplement products.

For oxygen-sensitive ingredients including algal oil DHA, astaxanthin, and Coenzyme Q10, Pullulan capsules are the superior choice. Their compact molecular structure forms a dense oxygen barrier layer, with an oxygen transmission rate only 1/100 that of HPMC capsules and 1/30 that of gelatin capsules. This allows them to delay oxidative rancidity of the fillings without the addition of antioxidants. Additionally, Pullulan capsules disintegrate rapidly and completely in room-temperature water without the need for disintegrants, solving the industry pain point of HPMC capsules that tend to experience disintegration delay in extremely low-humidity environments. They are thus perfectly suited for high-value-added products with stringent shelf-life stability requirements.

2. Matching of Supply Chain and Brand Positioning

Beyond filler compatibility, the stability and controllability of the supply chain, as well as compliance certification for global markets, are core decision-making factors for brand owners in substrate selection. The two substrates have clearly differentiated positioning in this dimension:

As a semi-synthetic cellulose derivative, HPMC features highly mature production processes. The domestic supply chain has achieved large-scale and stable mass production with controllable costs and strong batch consistency. Moreover, its excellent weather resistance against high temperature and humidity makes it suitable for transportation and storage in extreme climatic markets such as tropical regions, where the capsule shells are less prone to adhesion, brittleness, deformation and other issues. HPMC is therefore the first choice for mass-market product lines, large-scale export products, and basic lines of vegetarian health supplements. In terms of compliance, HPMC is included in the Chinese Pharmacopoeia, the United States Pharmacopeia (USP), and the European Pharmacopoeia (EP), and has obtained FDA GRAS certification, enabling barrier-free access to all major global markets with a mature and clear compliance pathway.

Pullulan is a naturally fermented polysaccharide with no chemical modification throughout the production process, complying with the certification pathways for organic and non-chemical processing. It perfectly aligns with the world's mainstream high-end certification systems such as organic, clean label, and vegan/vegetarian standards, boasting a higher premium potential for clean labels. This makes it ideal for building technical barriers for high-end product lines and breaking the homogeneous competition in the high-end organic track. In terms of compliance, Pullulan is also included in the Chinese Pharmacopoeia, USP, and EP, and has passed FDA and EFSA safety certifications, meeting the certification requirements for global organic products and offering stronger adaptability to high-end markets.

3. Evolution of Product Portfolio Strategy

From the product layout of leading global enterprises, the model of a single substrate covering the entire product line is on the decline, and a differentiated strategy of matching substrates to product positioning has become an industry consensus.

An increasing number of brands have adopted a hierarchical selection logic: HPMC is used for basic nutrition lines and mass circulation lines to control costs, ensuring large-scale supply while meeting the core demands of basic plant-sourced ingredients and compliant overseas expansion; Pullulan is applied in high-value product lines such as functional oils, hangover relief and liver protection products, and oral beauty products. Leveraging its core advantages of rapid disintegration, antioxidant performance, and clean label certification, Pullulan supports the differentiated pricing and high-end brand positioning of such products, achieving a balanced balance between cost control and profit premium.

Conclusion

In summary, the selection of plant-based capsules has entered a refined stage driven by filler properties. There is no absolute superiority or inferiority between HPMC and Pullulan; the only distinction lies in their scenario compatibility. Formulation engineers and brand owners are required to conduct pre-validation and compatibility testing of substrates at the initial stage of formula development, in combination with the hygroscopy and oxygen sensitivity of raw materials and the compliance requirements of target markets, to fundamentally avoid quality and supply chain risks after product launch.

We welcome in-depth exchanges and discussions with industry R&D peers and brand partners on the stability data of the two types of capsules in specific applications, the detailed compliance certification rules for major global markets, and customized selection solutions.