Capsule, softgel or tablet: forms, excipients and how to choose

Open a pill organiser: a hard capsule sits alongside softgels, tablets and powder sachets. These forms are not interchangeable. The shell, excipients and release method determine what happens to the ingredient between bottle and intestine: preservation, release location and ease of swallowing. Here is how each form works, what excipients do and how to choose.

Hard capsule, softgel or tablet: what is the difference?

A hard capsule has two interlocking halves filled with powder, granules or microbeads. A softgel is one piece, softer and usually contains oil: the classic omega-3 or vitamin E form. A tablet is compressed powder with excipients ensuring cohesion. Pharmacy distinguishes hard and soft capsules.

What is a capsule made of?

Gelatin: the original shell

Gelatin comes from collagen in cattle or pig bones and hides, more rarely fish. Inexpensive, it opens quickly in the stomach, but is unsuitable for vegetarians and some religious restrictions. Crucially, it contains 13 to 16% water. Below 10% relative humidity it becomes brittle; in humid heat it softens. It can also “cross-link”: exposure to some aldehydes or warm, humid storage creates bonds slowing dissolution.

HPMC: the cellulose-based plant capsule

HPMC (hydroxypropyl methylcellulose, or hypromellose) is modified cellulose, authorised as additive E 464. At 50% humidity, it contains around 6% water versus 14% for gelatin. It remains flexible when dry and does not cross-link: better for moisture-sensitive powders such as probiotics.

Are HPMC capsules risky? In 2018, EFSA reassessed celluloses including HPMC and identified no safety concern at reported use levels. One nuance: depending on gelling agent, some HPMC capsules open more slowly, around four minutes versus one for gelatin in water at 37°C in a laboratory test. The review reporting these figures also notes that some publications come from capsule manufacturers: be cautious about “superior absorption” promises.

Pullulan: a fermentation-derived option

Pullulan (E 1204) is a polysaccharide obtained by fermenting starch with the microscopic fungus Aureobasidium pullulans. It is also used for plant-based capsules. Reassessed by EFSA in 2025, it raises no safety concern at current uses; only intakes of 10 g daily or more may cause mild digestive symptoms.

Enteric-coated or delayed-release capsule: what is it for?

An enteric-resistant capsule should cross the stomach without opening, then release contents in the intestine. The aim is to protect an acid-sensitive ingredient or spare the stomach. NADH is a good example: it degrades in acidic conditions, whereas its oxidised form NAD+ is mainly fragile in alkaline conditions. Also see our article on the difference between NAD+ and NADH.

Several technologies coexist: a coating dissolving only at intestinal pH, a shell itself containing such a polymer, or simply a slower-opening shell. A German team tracked them using MRI. In eight volunteers, HPMC capsules with an enteric polymer never opened in the stomach, even after 82 minutes; seven opened in the small intestine, one in the colon. In an earlier six-volunteer study, uncoated “delayed-release” capsules opened after an average of 37 minutes, versus around nine minutes for gelatin in a comparable study. Authors consider this type potentially insufficient when true gastro-resistance is needed. Both very small studies were funded by the tested capsules' manufacturer.

Tablets: coated, effervescent or prolonged-release

Tablets concentrate much ingredient in a small volume but require more excipients: binders, fillers, disintegrants and lubricants.

• Film-coated or coated: a thin polymer or sugar layer masks taste, protects against light and moisture, and facilitates swallowing.
• Effervescent: an acid and bicarbonate release carbon dioxide in water. These tablets often provide sodium. In a British observational study of nearly 1.3 million patients, sodium-containing effervescent or soluble medicines were associated with sevenfold higher odds of hypertension and 16% more cardiovascular events than sodium-free equivalents.
• Prolonged-release: a matrix, often HPMC-based, releases the ingredient over hours. These tablets must not be cut or crushed, risking release of the entire dose at once.

Powders, liquids, gummies and liposomal forms

When doses are in grams (creatine, collagen, fibre), powder is the practical choice; otherwise several capsules would be needed per dose. It allows dose adjustment but exposes ingredients to air and moisture with every opening. Liquids suit people struggling to swallow.

Gummies are pleasant, often sugary, with harder-to-control dosing. Analysis of 25 US melatonin gummies found 74 to 347% of the labelled quantity; only three matched within 10%. See our article on sleep and melatonin.

Liposomal forms enclose ingredients in tiny phospholipid vesicles intended to facilitate passage. Evidence remains thin and ingredient-specific. In a small trial of eleven adults, 4 g liposomal vitamin C gave higher blood levels than conventional vitamin C but lower than infusion. Glutathione, discussed in our article on glutathione, is often offered this way.

Excipients: what do they actually do?

An excipient has no intended health effect: it makes manufacturing, stability and precise dosing possible. In the EU, additives must be on an authorised list and the ingredient list.

Why add them? A 100 µg active dose does not fill a capsule: a bulking agent completes the volume, otherwise the dose would vary between capsules. Anti-caking agents and small amounts of lubricants prevent powder clumping and sticking to machines. Magnesium stearate, subject to persistent rumours, raises no EFSA concern at reported uses.

Titanium dioxide (E171): why was it banned?

Titanium dioxide whitened and opacified capsules, tablets and sweets. In May 2021, EFSA concluded it could no longer be considered safe as an additive: particles may accumulate in the body and genotoxicity (DNA damage) could not be excluded.

Regulation (EU) 2022/63 of 14 January 2022 removed it from foods including supplements from 7 February 2022, with transition until 7 August 2022. France had already suspended it in food from 2020. The regulation retained it as a medicinal colourant, planning reassessment within three years.

How can capsules be swallowed more easily?

In a survey of 1,051 German general-practice patients, 37.4% reported difficulty swallowing tablets and capsules. Of these, 58.8% had altered medication intake in ways potentially affecting safety or efficacy. The same team tested two techniques in 151 adults rating ease of swallowing themselves:

1. For a capsule, lean forward. Put it on your tongue, take water without swallowing, tuck your chin to your chest, then swallow with your head tilted forward. This helped in 88.6% of attempts (31 of 35).
2. For a tablet, use a bottle. Put it on your tongue, seal lips around a plastic water bottle opening, and drink by suction without admitting air. This helped in 59.7% of attempts (169 of 283).

Drink a large glass of water and stay seated or standing for a few minutes afterwards.

How should supplements be stored?

Keep bottles closed, away from heat, moisture and light, outside the bathroom, with their desiccant sachet. Probiotics are most fragile: follow storage instructions; some need refrigeration.

Which form should you choose for dose and ingredient?

• Small dose of dry powder (vitamins, minerals): capsule or tablet.
• Oil or fat-soluble ingredient: softgel.
• Acid-sensitive ingredient: enteric-resistant, coated or enteric-shell form.
• Moisture-sensitive powder: HPMC capsule and bottle with desiccant.
• Dose of several grams: powder.
• Swallowing difficulty: powder, liquid, or a capsule opened if permitted by the label.
• Vegetarian diet: HPMC or pullulan capsule.

Active quantity and chemical form matter as much as the shell: magnesium salts change elemental magnesium content (see our comparison of magnesium forms). Form can even change the effect: gymnema blocks sweet taste in contact with the tongue, not swallowed as a capsule (see our article on gymnema and sugar cravings).

Frequently asked questions

Can a capsule be opened?

Yes for an ordinary capsule if the label does not prohibit it: mix powder into fruit purée and take immediately. No for an enteric-resistant or modified-release capsule, where opening removes protection.

Capsule or tablet: which is better absorbed?

Neither is inherently better. A gelatin capsule opens in the stomach in under ten minutes on average, and immediate-release tablets are also designed to disintegrate quickly. Active dose and chemical form matter more.

What does “size 00” mean?

It is a standardised size code, from 000 for the largest capsule to 5 for the smallest. A 00 capsule is therefore large and harder to swallow.

Should a capsule be taken with hot water?

Not necessarily. In the laboratory, gelatin dissolves poorly below 30°C and quickly at body temperature. Some authors therefore suggest lukewarm water for gelatin capsules.

Is a plant-based capsule necessarily vegan?

No: “plant-based” describes the shell, not the contents. Powder may contain collagen or vitamin D3 from sheep's wool, for example. Check ingredients.

Do gelatin capsules contain pork?

Possibly: gelatin can come from cattle, pigs or fish; only the label or manufacturer can specify origin. HPMC and pullulan capsules contain none.

Conclusion

Gelatin or plant-based capsule, softgel, tablet or powder: each form addresses dose constraints, ingredient fragility or ease of use. HPMC better protects moisture-sensitive powders, an enteric-resistant shell protects acid-sensitive ingredients, and excipients mainly ensure accurate dosing. Three habits complete the picture: store dry, swallow with a large glass of water, read ingredients.

Sources

1. Al-Tabakha MM (2010). HPMC capsules: current status and future prospects. J Pharm Pharm Sci, 13(3), 428-442. doi:10.18433/j3k881
2. EFSA Panel on Food Additives and Nutrient Sources added to Food (2018). Re-evaluation of celluloses E 460(i), E 460(ii), E 461, E 462, E 463, E 464, E 465, E 466, E 468 and E 469 as food additives. EFSA Journal, 16(1), 5047. doi:10.2903/j.efsa.2018.5047
3. EFSA Panel on Food Additives and Flavourings (2025). Re-evaluation of pullulan (E 1204) as a food additive and new application for its extension of use. EFSA Journal, 23(3), e9267. doi:10.2903/j.efsa.2025.9267
4. EFSA Panel on Food Additives and Nutrient Sources added to Food (2018). Re-evaluation of sodium, potassium and calcium salts of fatty acids (E 470a) and magnesium salts of fatty acids (E 470b) as food additives. EFSA Journal, 16(3), 5180. doi:10.2903/j.efsa.2018.5180
5. EFSA Panel on Food Additives and Flavourings (2021). Safety assessment of titanium dioxide (E171) as a food additive. EFSA Journal, 19(5), 6585. doi:10.2903/j.efsa.2021.6585
6. European Commission (2022). Regulation (EU) 2022/63 of 14 January 2022 amending Annexes II and III to Regulation (EC) No 1333/2008 as regards the food additive titanium dioxide (E 171). Official Journal of the European Union, L 11. EUR-Lex
7. Wolfe KD et al. (2024). Long-Term Stability of Nicotinamide Cofactors in Common Aqueous Buffers: Implications for Cell-Free Biocatalysis. Molecules, 29(22), 5453. doi:10.3390/molecules29225453
8. Rump A et al. (2021). In vivo disintegration of HPMC capsules, delayed-release capsules and capsule-in-capsule combinations in healthy volunteers: MRI and salivary tracer study (descriptive title). Pharmaceutics, 13(12), 2002. doi:10.3390/pharmaceutics13122002
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10. George J et al. (2013). Association between cardiovascular events and sodium-containing effervescent, dispersible, and soluble drugs: nested case-control study. BMJ, 347, f6954. doi:10.1136/bmj.f6954
11. Cohen PA et al. (2023). Quantity of Melatonin and CBD in Melatonin Gummies Sold in the US. JAMA, 329(16), 1401-1402. doi:10.1001/jama.2023.2296
12. Davis JL et al. (2016). Liposomal-encapsulated Ascorbic Acid: Influence on Vitamin C Bioavailability and Capacity to Protect Against Ischemia-Reperfusion Injury. Nutr Metab Insights, 9, 25-30. doi:10.4137/NMI.S39764
13. Schiele JT et al. (2013). Difficulties swallowing solid oral dosage forms in a general practice population: prevalence, causes, and relationship to dosage forms. Eur J Clin Pharmacol, 69(4), 937-948. doi:10.1007/s00228-012-1417-0
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Food supplements do not replace a varied, balanced diet or a healthy lifestyle. Ask a healthcare professional for advice if you are taking medication, pregnant or breastfeeding.