Technical · updated 10 August 2026
This compares two processes and what they ask of your equipment. It is not advice on which to use for anything, and these are not FDA-approved medical devices. Speak to a licensed healthcare professional about use.
The difference is chemistry, not technique
These are often treated as the same job with a different liquid in the jar. They are not, and nearly every practical difference below follows from one fact about the molecules.
Vegetable oil contains unsaturated fatty acids, meaning fatty acids with carbon–carbon double bonds along the chain. Ozone attacks those bonds and forms ozonides and related peroxides. The ozone ends up chemically bound into new and comparatively stable molecules, and the oil thickens as that happens.
Glycerin is saturated. There are no carbon–carbon double bonds anywhere in it, only three hydroxyl groups on a three-carbon backbone. There is nothing for ozone to add across, so no ozonides form. Ozone dissolves into the liquid and oxidises those hydroxyl groups slowly.
What that changes in practice
| Ozonated oil | Ozonated glycerin | |
|---|---|---|
| Reaction | Ozone adds across C=C bonds and forms ozonides | No ozonides are possible. Ozone dissolves; hydroxyls oxidise |
| Visible endpoint | Thickens to a gel or paste | None. It looks much the same when you finish |
| Typical run | Days to weeks | Hours |
| Back-pressure | Low at first, climbs as it gels | High from the first minute, roughly constant |
| Where the ozone ends up | Bound into the oil | Dissolved, and leaving from the moment you stop |
| Keeping | Longer. Cold storage extends it | Short. Cold, dark and sealed, and still declining |
Why the run times are not comparable
An oil run is long because you are driving a slow addition reaction towards completion, and you can see how far it has gone by how thick the oil is. Stopping early gives you a genuinely less-reacted product.
A glycerin run has no such reaction to complete. Past the point where the liquid is carrying about as much ozone as it will hold, additional hours are not building anything. They are feeding more ozone through a liquid that is already saturated, and slowly oxidising it further.
This is the single most common mistake we see described online: an oil protocol, measured in days, applied to glycerin.
Shelf life surprises people
Because oil binds ozone into ozonides, an ozonated oil keeps something of what you made for a reasonably long time, especially cold.
Glycerin holds ozone in solution instead, and dissolved ozone escapes. It begins escaping the moment the bubbler stops. Cold, dark, sealed, and full to the top with as little headspace as you can manage all slow it down. None of them stop it.
The practical consequence: with oil you can make a batch and come back to it. With glycerin, whatever you have is at its peak when you switch the generator off.
Which is harder on the equipment
Different demands rather than one being simply worse.
- Oil punishes duration. Days of continuous running is a real duty-cycle question for the generator, and the diffuser clogs progressively as the gel forms.
- Glycerin punishes viscosity. The run is short, but the pump works against high back-pressure from the start, and a fine diffuser may not pass usable bubbles at all.
- Both punish the wrong materials. Glass, silicone, PTFE and 316 stainless in each case. See the materials guide.
- Both off-gas. Oil for longer because the run is longer; glycerin more per hour because thick liquid sheds bubbles into the headspace. Read the safety and ventilation guide for either.
What we will and will not tell you
We build and sell the hardware, and the paragraphs above are about hardware and chemistry. We will not tell you which of these to make, what to do with either, or that either does anything for anyone. Those are not questions about equipment, and our answering them would not make them so.