When the natural products industry first began, there were four basic types of delivery systems for dietary supplements: tablets, capsules, powders and liquids. Today, those basic four still exist, and still probably represent the majority of supplements on the market. However, delivery system options have expanded and now include soft gels, liquid caps, lozenges and gummies (the solid dosage delivery forms), as well enteric and other coatings which can be used for certain solid dosage delivery forms. All of these choices give rise to the question, “Do any one of these delivery forms have advantages over other delivery forms?” The answer is yes, although it depends upon the nutraceuticals to be delivered, and the purpose for which they are being delivered. This article will explore these various delivery systems, and identify which are most appropriate for specific nutraceuticals, in specific situations.

Tablets and Capsules

Tablets and capsules are the primary delivery forms currently used in dietary supplements. The United States Pharmacopeia (USP) require a disintegration (breakdown) time of 45 minutes in water, while being agitated in laboratory equipment designed to simulate peristalsis, the muscular action of the stomach and gastrointestinal tract. The basic thinking is, if it can breakdown in water which has a neutral pH of about 7, then it should have no problem breaking down in acidic pH of gastric juices which have a pH of 1.5 to 3.5. Therefore, a broad variety of nutraceutical in either tablets or capsules should be adequately available for absorption in humans.

Nevertheless, tablets and capsules each offer their own advantages. Since tablets are available in a plethora of sizes and shapes, whereas capsules are available in a limited number of sizes, tablets can generally fit a higher dose of nutraceuticals. Consequently, in some situations it is possible to offer a smaller serving size with tablets. For example, 3,000 mg of a given nutraceutical is more likely to fit into three tablets, whereas it would probably require four capsules to achieve the same dose.

Conversely, capsules offer the advantage of requiring few excipients in their manufacture. For example, tablets require binding agents to hold them together, while capsules do not. Also, research has demonstrated that many people tend to prefer capsules over tablets.1,2,3 In fact, depending on the study, capsules were preferred over tablets by 74 percent4 to 90 percent5 of participants. The reasons consumers give for this preference is ease of swallowing as the most important attribute with speed of action and gentleness on the stomach increasing in importance.6 In addition to the standard gelatin, capsules are now available in vegetarian options as well, including hydroxypropyl methylcellulose (HPMC), carrageenan (derived from seaweed) and pullulan (fermented from tapioca).

Lozenges

Lozenges are essentially a type of tablet that is meant to remain in the mouth until it dissolves. Lozenges vary in size depending upon the nutraceutical and application. This delivery form is ideal for certain nutraceuticals, which should remain in the mouth for a period of time. For example, zinc lozenges (often used in the treatment of the common cold)7 can coat the throat while dissolving, which helps localize the application of the zinc where it may do the most good. Another example is the BLIS K12 strain of the probiotic Streptococcus salivarius, which resides in the oral cavity, and, which has been shown to reduce the number of episodes of certain throat infections/tonsillitis, acute otitis media (ear infection)8,9 and reduce various species of bacteria involved in halitosis.10,11,12 A BLIS K12 supplement, therefore, needs to remain in the mouth long enough (i.e. a few minutes) for colonization to take place.

Smaller lozenges (i.e. micro-lozenges or dots) can also provide a sublingual (under the tongue) or buccal (mouth or cheek) delivery form for some nutraceuticals. The classic example of this is vitamin B12. Research from back in the early 1980s demonstrated that sublingual B12 administration increased blood serum levels of vitamin B12 by 90 percent. From these results it was evident that B12 could be readily absorbed via the sublingual plexus and buccal cavity directly into the blood stream.13 Research published in 200314 further verified that sublingual B12 was effectively absorbed. The significance of this these sublingual vitamin B12 studies is that that other research demonstrated that as little as 1.2 percent of dietary vitamin B12 is absorbed.15

Another example is melatonin, which has been shown in multiple studies to be an effective sleep aid.16,17,18 However, research also shows that that 44-90 percent of a standard melatonin supplement absorbed into the blood is cleared by the liver in a single passage,19 leaving less melatonin available to do its job. In contrast, other research20 shows that the amount of melatonin absorbed in the mouth and reaching systemic circulation was 80 percent greater than the standard oral tablet, and the peak concentration of melatonin was 50 percent higher as well. Furthermore, research has shown that sublingual melatonin has anti-anxiety effects,21,22 and improved day sleep and night alertness in those working the night shift.23

Soft Gels

People generally perceive soft gels as being easier to swallow than tablets.24 This delivery form is particularly suitable for oil-based nutraceuticals, such as fish oil and certain herbs like the liposterolic extract of saw palmetto. Sometimes powdered nutraceuticals that are not oil based are included in soft gels, but this requires their being mixed with food-grade oil so that they can then be included in the soft gel. There is no advantage to this, but sometimes it is necessary if a formulation consists of a mix of oil- and non-oil-based nutraceuticals. Soft gels also provide a method of consuming an oil/liquid nutraceutical without having to taste it.

As with capsules, soft gels are also available in vegetarian forms as well as the conventional gelatin forms. Typically gelatin soft gels are derived from bovine sources, although fish-based gelatin is also available.

Liquid Capsules

Liquid-filled capsules can also be used for liquid or oil-based nutraceuticals, and for the most part offer the same benefits as soft gels. In addition, liquid-fill capsules are also available in vegetarian forms as well as gelatin.

Gummies

Gummies are the preferred nutraceutical delivery form for children (and rapidly gaining in popularity among adults with pill fatigue), displacing chewable tablets in that role. The obvious advantage is that it is easy to get children to eat gummies, which they associate with candy. That assumes, of course, that the gummies are palatable. Some nutrients, such as iron, don’t taste good in a gummy, and so are often not included in gummy formulations.

Previously, only gelatin-based gummies were available, but now pectin-based gummies have also entered the marketplace. This has advantages for those who prefer a vegetarian and/or non-GMO gummy.

Powders

Powders are an effective method for delivering dietary supplements with ingredients that need to be consumed in gram amounts rather than in milligrams. Examples include proteins, collagen, fibers, creatine, etc. In addition, powders do not require the same degree of breakdown as tablets or capsules, so they may be more easily digested. Furthermore, they can be mixed with other nutraceuticals and consumed as a shake, smoothie or other drink. The disadvantage of powders is that some of them are not particularly palatable, including many herbs (especially root-based materials). In these situations, bitter masking agents may be employed to improve palatability. Also, since powders have no protective coating or capsule surrounding them, they may not always have the same long-term stability as solid dosage forms.

A newer delivery method for powders is to sprinkle them on foods to enrich intake of a given nutraceutical (e.g. protein). The sprinkle method means that not all powders are required to be consumed as part of a drink mix.

Liquids

As with powders, liquids also offer an effective method for delivering liquid and oil-based nutraceuticals that need to be consumed in gram amounts, and can also be mixed with other nutraceuticals and consumed in a shake, etc. However, taste and consistency (mouth feel) can be an issue depending upon the material being used. Also, oils and some liquids are more susceptible to oxidation, so they may need to be refrigerated after opening to help maintain stability.

Some herbal extracts are also available in liquid form, and are frequently preferred among herbalists for their quick onset of action—although taste can also be an issue for some. In addition, some liquids are provided in the form of a spray bottle, wherein the liquid nutraceutical is sprayed into the mouth. In this case, the liquid can then be swallowed or, depending upon the nutraceutical, left in the mouth for buccal absorption.

Enteric and Other Coatings

Enteric coating is a polymer barrier applied on solid dosage form mediations and supplements for the purpose of protecting them from the acidic pH of the stomach. Such a coating would have advantages where there is a preference for a supplement to break down in the intestines rather than in the stomach. An example of such a supplement is a fish oil softgel. When broken down in the intestines instead of the stomach there is a lesser chance for experiencing “fish burps” and other types of undesirable reflux.

Another example is a probiotic supplement. Since some probiotic microorganisms can be partially or completely destroyed in gastric acid, an enteric coating offers a distinct advantage25—although there are other types of delivery systems that offer similar or better protective benefits for probiotics. These include, alginate coating,26 succinylated -lactoglobulin coating27 and BIOtract. My personal favorite is BIOtract, a patented technology using a type of pectin that protects the majority of a supplement’s probiotics from gastric acid, helping to ensure that a significantly higher percentage of microorganisms reach the intestines alive.28 In laboratory research, data confirmed that the probiotics are afforded protection through acid exposure and continually release through the testing period in simulation of the passage through the human digestive tract.29,30

Conclusions

Many dietary supplement delivery forms exist, and all have their advantages and disadvantages depending upon the nutraceutical and the application. I think the important take-home message here is that there is no single delivery system which will be effective for all types of supplements. Rather, it is important to select a delivery system that is appropriate for each dietary supplement product. VR

References:

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Gene Bruno, MS, MHS, the dean of academics for Huntington College of Health Sciences, is a nutritionist, herbalist, writer and educator. For more than 30 years he has educated and trained natural product retailers and health care professionals, has researched and formulated natural products for dozens of dietary supplement companies, and has written articles on nutrition, herbal medicine, nutraceuticals and integrative health issues for trade, consumer magazines and peer-reviewed publications.