The hard capsule looks like the simplest possible dosage form, but the shell material is a formulation decision in its own right — it sets the moisture the fill is exposed to, which diets and religious markets can use the product, and in the case of gelatin, an allergen line on the label.
This guide compares gelatin, HPMC and pullulan hard capsule shells, and what each one changes about the finished product and its label.
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💬 Choosing a hard capsule shell for a Japan-made product? We match the shell material to the fill and to your label markets before quotation. See Japan-made supplement OEM.
Gelatin, HPMC or pullulan
Gelatin is the lowest-cost, most moisture-permeable option; HPMC is a plant-derived cellulose shell that holds less water; pullulan is a fermentation-derived shell that combines low moisture with a very good oxygen barrier.
| Shell material | Source | Typical shell moisture | Best suited to |
|---|---|---|---|
| Gelatin | Bovine, porcine or fish collagen | Around 13–16% | Standard fills that are not moisture-sensitive; lowest cost |
| HPMC (hydroxypropyl methylcellulose) | Plant cellulose (wood pulp or cotton derivative) | Around 4–6%, lower and more stable than gelatin | Hygroscopic or moisture-sensitive fills; vegetarian and halal/kosher markets |
| Pullulan | Fermentation of starch sugars by a food-grade mould culture | Comparable to or lower than HPMC | Moisture- and oxygen-sensitive fills (e.g. probiotics, some vitamins); premium vegetarian positioning |
A capsule shell’s own moisture content matters because it can migrate into a hygroscopic fill (one that readily absorbs water) during storage, softening a powder fill or degrading a moisture-sensitive active. HPMC and pullulan both carry markedly less water into the fill than gelatin does, which is why they are the default choice for probiotics, effervescent blends and some plant-extract powders.
Moisture, oxygen and hygroscopic fills
The shell that best protects a hygroscopic fill is not always the one with the lowest sourcing cost, so the fill’s own moisture sensitivity should be tested before the shell is fixed.
| Property | Gelatin | HPMC | Pullulan |
|---|---|---|---|
| Shell moisture content | Higher | Lower | Lower |
| Oxygen barrier | Moderate | Lower than gelatin | Notably good — among the better oxygen barriers of the common shell materials |
| Brittleness in low humidity | Can become brittle if stored too dry | More stable across a humidity range | Stable, but shell cost is typically the highest of the three |
| Fit for hygroscopic or moisture-sensitive fills | Weakest of the three | Good | Best of the three |
A brand filling a live-culture probiotic, a moisture-sensitive botanical extract, or an effervescent-style powder should treat the shell material as part of the stability study, not a packaging afterthought — the wrong shell can shorten the product’s real shelf life even when the fill formula itself is stable.
💬 Formulating a moisture-sensitive fill (probiotics, effervescent blends, hygroscopic extracts)? Tell us the fill and we recommend a shell before you commit to a specification.
Vegetarian, halal and kosher implications
HPMC and pullulan are plant- or fermentation-derived and free of animal sourcing questions; gelatin’s status depends on species and, for halal and kosher markets, on how the source animal was raised and processed.
| Shell material | Vegetarian/vegan | Halal | Kosher |
|---|---|---|---|
| Bovine gelatin | No | Depends on slaughter method and certification | Depends on slaughter method and certification |
| Porcine gelatin | No | Not halal | Not kosher |
| Fish gelatin | No (not vegetarian) | Generally acceptable, subject to species and certification | Generally acceptable, subject to species (fin/scale rules) and certification |
| HPMC | Yes | Yes (plant-derived) | Yes (plant-derived) |
| Pullulan | Yes | Yes (fermentation-derived) | Yes (fermentation-derived) |
A brand that wants a single shell to clear vegetarian, halal and kosher claims at once should default to HPMC or pullulan rather than trying to certify a gelatin source for all three — certification of an animal-derived shell adds a documentation step that a plant- or fermentation-derived shell does not need.
Gelatin as a labelled allergen in Japan
Gelatin sits on Japan’s list of 20 recommended (not legally mandatory) allergen-labelling items, alongside foods such as beef, pork, chicken, salmon and soy.
Japan’s Consumer Affairs Agency (CAA) maintains two allergen categories under the Food Labelling Act: a shorter list of mandatory items and a longer list where labelling is recommended but not compulsory. Gelatin has long been on the recommended list, most recently reconfirmed in the CAA’s 2024 review of the recommended-item list (which added macadamia nut and removed matsutake mushroom, leaving the total at 20 items with gelatin still included). This applies to gelatin as a food ingredient generally, including as a capsule shell material, so a gelatin capsule sold as a Japanese food product should carry the recommended allergen note even though it is not a mandatory declaration under Japanese law. Confirm the current wording with the factory’s labelling team, since the recommended list is reviewed periodically.
Sourcing rules for bovine gelatin
Bovine gelatin used in Japan and the EU is produced under specific-risk-material exclusion rules tied to BSE controls, not an outright restriction on cattle-derived gelatin.
Both Japan and the EU regulate which parts of cattle may be used as a gelatin or collagen source, rather than banning bovine gelatin outright. In Japan, the Ministry of Health, Labour and Welfare’s BSE measures exclude specified risk material — the skull (except the lower jaw) from cattle over 12 months old, and the spinal column from cattle over 30 months old — from gelatin and collagen raw material, with manufacturing standards (defatting, acid or alkaline treatment) for bone-derived material to reduce infectivity, alongside recognition that the gelatin production process itself reduces BSE infectivity by several orders of magnitude. In the EU, bovine gelatin production is governed by Regulation (EC) No 853/2004 (Annex III, Sections XIV–XV) and Regulation (EC) No 1069/2009 on animal by-products, and the European Food Safety Authority (EFSA) issued a further scientific opinion on the BSE risk of bone-derived bovine gelatin and collagen in 2024. A specification for a bovine gelatin capsule should record the country of origin of the raw material and the supplier’s compliance with these sourcing rules, not just the gelatin grade.
Before you ask for a quotation
A factory can quote a hard capsule accurately once the shell material, fill type and target markets are fixed.
- Shell material: gelatin (and species), HPMC or pullulan
- Fill type and whether it is hygroscopic or oxygen-sensitive
- Capsule size and any colour requirement
- Vegetarian, halal or kosher claims needed
- Countries you will sell in, and their allergen-labelling rules
- Any existing stability data on the fill
💬 Ready to specify a hard capsule made in Japan? Send us the fill and target markets and we match the shell material to both.
Frequently asked questions
1. Is HPMC or pullulan better for a probiotic fill?
Both hold less moisture than gelatin and suit a live-culture fill better than gelatin does. Pullulan additionally offers a stronger oxygen barrier, which can matter for oxygen-sensitive strains, but HPMC is the more widely available and lower-cost of the two.
2. Does a gelatin capsule always need an allergen note in Japan?
Gelatin sits on Japan’s 20-item recommended (not mandatory) allergen list, so it is common practice to note it even though the law does not require it. Confirm the current wording with the factory, since the recommended list is reviewed periodically.
3. Can bovine gelatin still be used after BSE controls?
Yes. Japan and the EU restrict which cattle materials may be used as source material (excluding specified risk material such as skull and spinal column above set cattle ages) rather than banning bovine gelatin, and the gelatin manufacturing process itself is recognised as reducing BSE infectivity.
4. Is fish gelatin automatically halal or kosher?
Generally more straightforward than bovine or porcine gelatin, but not automatic — species and certification still need confirming, since kosher rules in particular are species-specific for fish.
5. Why would a brand pay more for a pullulan shell over HPMC?
Mainly for the oxygen barrier and for a fermentation-derived (rather than wood-pulp-derived) plant positioning some brands prefer, both of which can matter for oxygen-sensitive fills or for label storytelling, at a higher shell cost than HPMC.
Sources: Japan Ministry of Health, Labour and Welfare, BSE countermeasures for cattle-derived gelatin and collagen, including specified-risk-material exclusion rules (mhlw.go.jp/content/11130500/000508027.pdf and related MHLW/MAFF materials); Regulation (EC) No 853/2004, Annex III, Sections XIV–XV, and Regulation (EC) No 1069/2009 (eur-lex.europa.eu); EFSA Journal 2024, “BSE risk posed by ruminant collagen and gelatine derived from bones” (efsa.onlinelibrary.wiley.com/doi/10.2903/j.efsa.2024.8883); Japan Consumer Affairs Agency (CAA), 2024 review of recommended allergen-labelling items adding macadamia nut and removing matsutake, 20-item list including gelatin (caa.go.jp policy materials, cross-checked against secondary summaries); Japan Food Sanitation Act Enforcement Regulation, Annex 1 (designated food additives, including hydroxypropyl methylcellulose) (laws.e-gov.go.jp); Consumer Affairs Agency, Specifications and Standards for Food Additives, Section F use standards, with no specific use standard for HPMC (caa.go.jp). Checked on 12 October 2026.