A small paper sachet inside a supplement bottle looks like an afterthought, but for some products it is doing more work than the bottle itself. Moisture and oxygen degrade active ingredients, soften capsule shells and shorten shelf life, and a desiccant or oxygen absorber is often the cheapest way to buy back months of stability.
This guide covers the common desiccant and oxygen absorber types used in Japan-made supplements, which products need them, and how they should be labelled so nobody mistakes them for something edible.
💬 Not sure whether your product needs a desiccant or oxygen absorber? We assess moisture and oxygen sensitivity as part of the formulation review. See Japan-made supplement OEM.
Desiccant and absorber types
Silica gel handles general moisture control, clay desiccants are a lower-cost alternative, and oxygen absorbers protect against oxidation that a desiccant cannot address.
| Type | What it is | Strengths | Watch-outs |
|---|---|---|---|
| Silica gel | Porous silicon dioxide beads in a small sachet | High moisture absorption capacity, widely available, inert | Absorbs only moisture, not oxygen |
| Clay (montmorillonite) desiccant | Natural clay mineral in sachet form | Lower cost than silica gel, adequate for moderate moisture control | Lower absorption capacity than silica gel for the same sachet size |
| Molecular sieve | Synthetic zeolite with a very uniform pore size | Strong moisture absorption even at low humidity, works at higher temperatures | Higher cost; usually reserved for the most moisture-sensitive actives |
| Oxygen absorber | Small sachet of iron powder that reacts with oxygen, or a non-iron equivalent | Removes oxygen from the sealed headspace, slows oxidation of fats, probiotics and some vitamins | Does not control moisture; some iron-based types are unsuitable near metal-detection lines and need separate handling |
Which products need them
Probiotics, powders and softgels are the formats most likely to need a desiccant, an oxygen absorber, or both.
- Probiotics. Live bacterial counts fall with both moisture and oxygen exposure, so probiotic capsules and powders commonly ship with a desiccant, an oxygen absorber, or a combined sachet, and increasingly in moisture-barrier capsules or blisters instead of or alongside a sachet.
- Powders and granules in a bottle or pouch. A wide bottle opening or a resealed pouch reintroduces humidity every time it is opened, so a sachet buys back shelf life between uses.
- Softgels. Gelatin or plant-based softgel shells absorb or lose moisture depending on ambient humidity, which changes their texture and can affect seal integrity; some softgel products use a desiccant in the bottle for this reason.
- Tablets and hard capsules with moisture-sensitive actives. Vitamin C, certain probiotics-adjacent enzymes and some botanical extracts are more moisture-sensitive than the base dosage form and may need a sachet even when the format itself does not usually require one.
- Oxidation-prone oils. Fish oil, krill oil and other lipid actives benefit more from an oxygen absorber than a desiccant, since oxidation rather than moisture is the main degradation pathway.
Labelling the sachet
Every desiccant or oxygen absorber sachet placed inside a supplement pack must be clearly marked as not for consumption, in a form the end consumer will notice.
Sachets are typically printed with wording such as “Do not eat” or “Silica gel — do not eat”, often alongside a pictogram, and in Japan the same convention is followed for both silica gel and oxygen-absorber sachets sold into food and supplement packaging. For an export product, add the equivalent wording in the languages your label already carries, since a Japanese-only warning is not enough for a consumer who cannot read it. Where the destination market has its own convention or required wording for desiccant or oxygen-absorber warnings, follow that market’s wording rather than assuming the Japanese phrasing translates directly.
💬 Need help deciding which sachet type suits your formula, and how to word the safety label? Tell us the dosage form and moisture sensitivity.
Before you ask for a quotation
- Dosage form (tablet, hard capsule, softgel, powder, probiotic)
- Known moisture or oxygen sensitivity of the actives
- Preferred sachet type: silica gel, clay, molecular sieve or oxygen absorber
- Whether a combined moisture-and-oxygen sachet is preferred over two separate sachets
- Bottle, blister or pouch format, since this affects sachet placement
- Languages required on the “do not eat” warning
💬 Ready to add the right desiccant or oxygen absorber to your Japan-made formula? Send us the formula and packaging format.
Frequently asked questions
1. Can I use a desiccant and an oxygen absorber together?
Yes, and it is common for probiotics and other formats sensitive to both moisture and oxygen. Some suppliers offer a combined sachet rather than two separate ones.
2. Do stick packs and pouches need a desiccant if they are single-serve?
Usually not for the individual serving, since it is consumed at once, but the outer carton or the bulk stock before packing may still need moisture control during storage and transport.
3. Is an iron-based oxygen absorber safe near metal detectors on the production line?
It can trigger false positives, which is a production-line handling question for the factory rather than a consumer safety issue. Ask the factory how they manage this if your product uses metal detection as a quality-control step.
4. Why do some softgel products include a desiccant when the capsule shell already seals the fill?
The shell itself is sensitive to ambient humidity — too dry and it can crack, too humid and it can soften or stick — so a desiccant in the bottle helps stabilise the storage environment around the capsules, not just the fill inside them.
5. What should the “do not eat” warning say for an export product?
At minimum, wording the consumer can read in their own language, ideally alongside the pictogram already printed on the sachet. Follow your destination market’s own convention if it differs from the Japanese-style wording.
Sources: Standard food and supplement industry practice for desiccant and oxygen-absorber sachet labelling in Japanese and export packaging. Checked on 25 September 2026.