Capsules or tablets: how to choose the form of a food supplement

The form of a supplement tells the story of the problem its formulator had to solve. A tablet is created when the dose is too high to fit into a capsule. A capsule, on the other hand, holds the powder as it is, without compressing it.

The gastro-resistant coating protects active ingredients that the stomach's acidic environment would damage. The softgel encapsulates oily ones, while the sublingual tablet dissolves under the tongue, skipping the passage through the stomach altogether. Choosing between capsules and tablets therefore means understanding what problem that form solves for that ingredient.

Why "capsules or tablets" is the wrong question

Those who look for a winner will always find one. Just look at who provides the answer: almost all comparisons available in Italian on this topic conclude with a preference, and the one expressing it generally produces that very form. In production, however, that winner does not exist.

A pharmaceutical form is a container designed around a content. Four very practical questions are enough to decide which one to use. How much active ingredient must be in one dose, and how sensitive that active ingredient is to acidity, humidity or heat. Then, whether it dissolves in water or in fats and where it needs to be released.

The answers lead to a different form every time. And for the same ingredient, they can change when the dose changes.

This is easier to see by looking at an entire catalogue instead of a single product. In ours, there are eleven products and five different forms: tablets, vegetable capsules, gastro-resistant capsules, softgels and sublingual tablets. This is the result of eleven technical decisions made one at a time, each for its own ingredient. The two gastro-resistant ones contain enzymes; the sublingual ones are the two products for which it is better to skip gastric passage, and the three with the highest dose are in tablet form.

• TabletWhen the dose is high
• CapsuleWhen the powder should not be compressed
• Gastro-resistantWhen acidity is the issue
• SoftgelWhen the active ingredient is oily
• SublingualWhen the stomach is bypassed

The tablet: when the raw material can be compressed

A tablet is obtained by compressing a mixture of active ingredients and excipients until it takes on a stable form. The first condition concerns the raw material: it must be granulated or otherwise suitable for direct compression, and it must withstand the heat and pressure of the process without being altered. Active ingredients that degrade under these conditions take another path. This is why the enzymes in our catalogue are in capsule form.

When that condition is met, the tablet offers an advantage in density: in the same space, it holds much more active ingredient than a capsule, because the powder is compacted rather than simply contained. With daily doses in the order of grams, the difference is immediately apparent. In the daily dose of four tablets, Glucosamine + Chondroitin + MSM provides 1,000 mg of glucosamine sulphate, 500 mg of chondroitin sulphate, 500 mg of MSM and 80 mg of vitamin C: over two grams of active ingredients per day.

A product like this can also be made in capsule form, and what changes is the number of units to be swallowed and the size of each one. For our three tablets, the choice was deliberate: a small, round format that is easy to swallow, for products taken two or four times a day, every day.

For Potassium Citrate and Vitamin C + Bioflavonoids, there is an additional factor: a capsule shell would have added cost without adding anything for these active ingredients, which tolerate compression very well.

Regarding excipients, there are figures circulating that are worth putting straight. According to the most repeated version, a tablet necessarily requires a huge proportion of them. How many excipients are needed, however, does not depend on the form: it depends on the raw material. A raw material suitable for direct compression is compressed almost as it is, and the proportion of excipients remains low, around ten per cent.

A raw material that is difficult to work with requires more: it flows poorly, tends to stick to the punches, and absorbs moisture from the air. To make a tablet that can withstand transport and then disintegrate in the right amount of time, binding, disintegrating or flow agents are needed.

For someone reading a label, the consequence is a practical one: the percentage of excipients says something about the raw material, rather than about the quality of the product. Two tablets of the same weight can have very different proportions and both be well formulated. We explain what each excipient is for, and what criteria we used to choose ours, in Excipients in supplements: what they are for and which ones matter.

You can make the estimate yourself, and all you need is the label. You divide the net weight of the pack by the number of units to get the average weight of one tablet. You compare this with the sum of the declared contents per dose, divided by the number of units that make up the dose. The difference is the proportion of excipients.

Here is the calculation for our three tablets, using only the data printed on the packaging:

These are calculated values, not declared ones: no label states the proportion of excipients, and this is an estimate based on the net weight. Anyone can do it, however, for any product, and it tells you much more than a generic percentage you read online. It is one of the calculations you can make from a label: we have explained how to read a label in this six-step guide.

A second advantage of the tablet is that it can be split: where there is a score line, the dose can be divided. When the line is missing, that too is a piece of information.

The hard capsule: when the powder is left as it is

A hard capsule is made of two half-shells that contain the powder without compressing it. It is the form chosen when the active ingredient is an extract that is better left uncompacted, or when the raw material would not be well suited to compression: it has poor flow, does not granulate well, or heat and pressure would alter it.

A capsule contains much more powder than you might think, and the sizes go up to 000. The constraint that really matters is another one: swallowing. A very large capsule is awkward to get down, and for a product to be taken every day, convenience is as important as a technical parameter.

In our catalogue, this is the case for 5-HTP, a dry extract of griffonia seeds standardised to 20%, and for Maca Nera Extra Forte, a 20:1 dry extract of the root: two plant-based powders that come in capsules as they are, with few processing aids.

The shell is an ingredient in its own right, and by law must be declared on the label. Our capsules are made of hydroxypropyl methylcellulose (HPMC), a modified cellulose of plant origin: it has a lower moisture content and is compatible with a vegetarian and vegan diet.

The other material in use, the most common on the market, is gelatin, of animal origin. You can always see which of the two you have in the list of ingredients, under "capsule shell".

The gastro-resistant capsule: when the problem is stomach acidity

A gastro-resistant capsule has a shell formulated to remain closed in the acidic environment of the stomach and release its contents further on, when the environment returns to near-neutral.

The reason lies in a physiological fact: in a fasted stomach, the pH is around 1.5-2, while in the small intestine it rises to about 6.8-7.2. Between the two environments there are several orders of magnitude. For proteins and enzymes, that difference matters: their function depends on their three-dimensional structure, and the gastric environment modifies that structure.

"Gastro-resistant" is a word with a measurable requirement behind it. The European Pharmacopoeia, in chapter 2.9.1 — Disintegration of tablets and capsules, describes a two-stage test for gastro-resistant forms: the dosage form is kept for two hours in 0.1 M hydrochloric acid, and in this phase it must remain intact; it is then transferred to a phosphate buffer at pH 6.8, where it must disintegrate within sixty minutes.

In our catalogue, there are two gastro-resistant capsules, and they are the two that contain enzymes: Bromelain 5000 GDU Gastro-Resistant and Nattokinase, whose label indicates taking one capsule a day with water, preferably away from meals. Both have the same shell: hydroxypropyl methylcellulose (E 464) and gellan gum (E 418).

We have covered the case of bromelain in detail, along with the meaning of GDU and the importance of the form for an enzyme, in the dedicated article.

• Stomach pH 1.5–2Capsule intact
• Small intestine pH 6.8–7.2Capsule open

pH increases from the stomach to the intestine

Softgels and oil-based capsules: when the active ingredient is fat-soluble

A softgel is a soft, sealed capsule containing a liquid: almost always an oil in which the active ingredient is dissolved or dispersed. It is the natural form for a fat-soluble molecule, i.e. one that dissolves in fats and not in water, because it delivers it already in solution rather than in powder form.

There are two in our catalogue, and they arise from this need: Ubiquinol with Kaneka QH®, in softgels, and Organic Astaxanthin Oil, in a capsule with Haematococcus pluvialis oleoresin dispersed in olive oil. Both labels indicate they should be taken with a meal, which is the practical consequence of their oily nature. We explained why the time of intake depends on the form and the ingredient in the article on when to take supplements.

The sublingual tablet: when the stomach is bypassed

A sublingual tablet is distinguished from others by its pathway, rather than its size. It dissolves by being held under the tongue, without water and without being swallowed, and the active ingredient is released to the oral mucosa.

It is the form chosen for Sublingual Melatonin 1 mg, to be dissolved under the tongue shortly before bedtime, and for Sublingual Vitamin B12, which provides 1,000 mcg of methylcobalamin in one tablet per day. For these two, the 'with or away from meals' question is posed in different terms, because gastric passage is not the main route. We explain what this vitamin does, why it might be lacking, and why the dose is so high in Vitamin B12: what it's for and when it's lacking.

Which form for which supplement: a summary table

Can you open a capsule?

Large capsules can be difficult to swallow, and this is a particular problem for those who take several every day. A lot depends on which capsule you have.

A standard hard capsule can generally be opened and the contents dispersed in cold, soft food to be consumed immediately. This remains a workaround compared to the intended use, because the taste will change. For some extracts, after all, the taste is the reason they are in a capsule.

A gastro-resistant capsule must never be opened. Opening it negates the function for which it was chosen: the contents would arrive freely in the stomach, i.e. the very place that shell is designed to bypass. The same applies to any modified-release form.

A tablet can only be split if it has a score line, and it should only be chewed if the label allows it — for some tablets that should be taken with plenty of water, it is expressly stated not to chew them. Sublingual tablets follow the opposite logic: they should be left to dissolve, because that is where they work.

In all cases, the definitive answer is on the label of the product you have in your hand, in the directions for use section. If difficulty swallowing is a recurring problem, or if you are taking medication, you should discuss it with your doctor or pharmacist, who can suggest alternatives in the same category.

1

• Standard hard capsule — It can generally be opened if swallowing is difficult

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• Gastro-resistant capsule — It must never be opened: opening it negates its function

Frequently asked questions

Is it better to take a supplement in capsules or tablets?

Neither form is better in absolute terms. A tablet allows for high doses in a small number of units; a capsule contains the powder without compressing it and is suitable for delicate extracts and active ingredients. The right form is the one chosen for that specific ingredient and for that specific dose, and it can be identified by the consistency between the declared contents, the number of units and the directions for use.

What are gastro-resistant capsules for?

They serve to keep the capsule closed in the acidic environment of the stomach, releasing the contents further along, where the pH returns to near-neutral. They are the form used for active ingredients that would be altered by gastric acidity, typically enzymes and proteins. The European Pharmacopoeia specifies a two-stage test for these forms, first in acid and then in a buffer at pH 6.8.

Can supplement capsules be opened?

A standard hard capsule can generally be opened, and the contents dispersed in cold food to be consumed immediately. A gastro-resistant capsule should never be opened, as this would negate the function of the shell. The definitive rule is the one written on the product label; in case of recurring difficulty in swallowing, it is advisable to speak with your doctor or pharmacist.

What is the difference between HPMC vegetable capsules and gelatine capsules?

HPMC, or hydroxypropyl methylcellulose, is a modified cellulose of plant origin; gelatine is of animal origin. HPMC has a lower moisture content and is compatible with vegetarian and vegan diets. The shell material is declared on the label in the list of ingredients, under "capsule shell".

Why are some supplements in tablets and others in capsules?

Because the dose and the raw material are different. When the daily intake is in the order of grams, the tablet is the form that contains it in a small number of units. When the active ingredient is a powdered extract, or when the raw material is not well suited to compression, the capsule contains it without compressing it.

How many excipients does a tablet contain?

It depends on the raw material, not the form: a raw material suitable for direct compression requires a low proportion, around ten per cent, while one that is difficult to process requires more. The estimate is made by dividing the net weight by the number of units and comparing the result with the declared contents per dose.

Do gastro-resistant capsules dissolve in the stomach or the intestine?

They are formulated to remain intact in the stomach and to release their contents further along, in the small intestine, where the pH is near-neutral. This is exactly what the official test verifies: no disintegration for two hours in 0.1 M hydrochloric acid, and disintegration within one hour in the pH 6.8 buffer.

Can sublingual tablets be swallowed?

They are designed to dissolve under the tongue, and the label states this explicitly. Swallowing them whole means using them in a way other than that for which they were formulated. The correct way to use them is always the one stated on the packaging.

Further reading

• How to read a supplement label: a practical six-step guide
• Excipients in supplements: what they are for and which ones matter
• Bromelain 5000 GDU: a complete guide, common myths and gastro-resistance
• Supplements in the morning or evening, on a full or empty stomach: a practical guide

References

• Legislative Decree 21 May 2004, no. 169 — regulation of food supplements, which are marketed in pre-dosed forms.
• Regulation (EU) No 1169/2011 — provision of food information to consumers: the capsule shell is an ingredient and must be declared on the label.
• European Pharmacopoeia (Ph. Eur.), chapter 2.9.1 Disintegration of tablets and capsules — disintegration test for solid oral forms and, for gastro-resistant forms, a two-stage test in 0.1 M hydrochloric acid and in phosphate buffer at pH 6.8.