How liquid supplement drops are made
Drops are the fastest line to run and the hardest to get right: the chemistry of keeping an active dissolved, stable and tasting acceptable in a small bottle is where most liquid products fail. D3+K2, magnesium, chlorophyll, sleep blends and mullein all run here.
1. Choose the carrier system
| Carrier | For | Notes |
|---|---|---|
| Vegetable glycerin (+ water) | Botanical extracts, sleep blends, mullein, soursop | Alcohol-free, sweet, self-preserving at high glycerin ratio |
| MCT oil | D3 + K2, astaxanthin, oil-soluble actives | No water = no microbial risk; light-protect in amber glass |
| Purified water (+ preservative) | Ionic magnesium, chlorophyll, vitamin blends | Needs preservative and pH control; flavoring critical |
2. Dissolve, emulsify or suspend
Actives are dissolved in the carrier under controlled temperature. Oil actives going into a water base are emulsified with lecithin or gum arabic under high shear, producing a stable emulsion that does not separate on the shelf. Some botanicals are suspensions — the label says shake before use. Flavor (mint for chlorophyll, berry for sleep blends) and, where needed, a sweetener are added last.
3. Filtration and hold
Solutions are filtered (5 µm, then 1 µm for clear products) into a holding tank; density and pH are measured because both change fill accuracy and preservative efficacy.
4. Filling and closing
Volumetric or peristaltic fillers dose 30 ml or 60 ml into amber glass (or PET) bottles. Dropper assemblies (glass pipette with bulb, or plastic child-resistant dropper) are torqued on and checked for seal. Fill volume is checked every 15 minutes; the bottle is weighed against a density-corrected target.
5. Labeling and boxing
Wrap label or front/back labels applied on the line; optional folding carton. Batch and expiry are inkjet printed.
QC release
| Test | Why |
|---|---|
| Active assay | Label claim (D3 in IU, K2 MK-7 in mcg, magnesium in mg, etc.) |
| pH and density | Stability, dose per dropper |
| Fill volume | Net contents |
| Microbial | Water-based products especially |
| Peroxide (oil-based) | Rancidity |
| Seal / leak | Dropper closure integrity |
Dose per dropper
A standard 1 ml dropper delivers about 20–30 drops. We formulate so that one full dropper (or a marked half) equals one serving, and the label states both the ml and the drop count. For D3+K2 that typically means 1,000–5,000 IU D3 with 100–200 mcg K2 per dropper; we set the exact dose with you.
What drives cost
- Bottle — glass + glass pipette is the biggest packaging cost in the format.
- Active concentration — a 5,000 IU D3 costs little more than 1,000 IU; magnesium and botanicals scale with dose.
- Carton — optional, adds cost and shipping volume.
Stock formulas: liquid vitamins and drops. Pet drops run on the same line — see pet supplements.
Frequently asked questions
Alcohol-free tinctures — how?
Vegetable glycerin replaces ethanol as the extraction and carrier solvent. It is sweet, stable and child-friendly. Oil-soluble actives (D3, K2, astaxanthin) use MCT oil instead.
Why do some drops separate?
Oil-in-water products need emulsification. We use lecithin or gum-based emulsifiers and a high-shear step; the spec sheet states whether the product is a solution, emulsion or suspension and whether to shake before use.
Glass or plastic?
Amber glass with glass pipette is the premium standard and protects light-sensitive actives. 59 ml PET with plastic dropper is lighter and cheaper to ship.
What is the shelf life?
18–24 months for most formulas. Water-based products contain a preservative system (potassium sorbate / sodium benzoate or a natural alternative) and are pH-controlled.