Glycerin vs. glycerol in eye drops: same thing?

Yes, they’re the same thing. Glycerin and glycerol are two names for one compound, and NIH’s PubChem database lists glycerin and glycerine as synonyms of glycerol. The federal over-the-counter rule for eye drops calls it glycerin, while Quell’s Drug Facts panel uses glycerol. Either way, its purpose on an eye drop label is “lubricant,” and the Uses line tells you what the drop is for.

One compound, three spellings

PubChem, the chemistry database run by the National Institutes of Health, files the compound under the name glycerol. Its synonym list includes glycerin, glycerine and 1,2,3-propanetriol, all pointing to the same chemical record. The “triol” in that last name refers to the three alcohol groups in the molecule.

• Glycerol: the name PubChem uses for the record, and the one on Quell’s carton.
• Glycerin: the name in the FDA’s over-the-counter eye drop rule, and common on US product labels.
• Glycerine: an alternate spelling of glycerin, also listed by PubChem.

If you’re scanning ingredient lists, for example to compare two products, search for all three.

What the federal rule calls it

Title 21 of the Code of Federal Regulations, part 349, covers over-the-counter ophthalmic drug products. Section 349.12 lists the approved demulcents, the ingredients that lubricate and protect the surface of the eye. Glycerin is on that list, along with polysorbate 80 and several others. The same section sets the allowed strength range for each.

A label can use either name, and the substance is the same. Quell lists it as Glycerol (1.0%), one of three active ingredients alongside Polysorbate 80 (1.0%) and Light Mineral Oil (0.5%). Our guide to what a demulcent is explains that group of ingredients.

Glycerin eye drops uses

Glycerin doesn’t have “uses” of its own on a label; the product does. The Uses section is where a Drug Facts panel states what the drop is for, and it applies to the whole formula. Quell’s reads: For use as a protectant against further irritation or to relieve dryness of the eye.

Next to each active ingredient, the panel also names its purpose. Quell’s panel gives glycerol the purpose “Lubricant,” the same purpose it gives polysorbate 80. Light mineral oil is listed as an “Emollient,” which the federal rule defines as an agent, usually a fat or oil, applied locally to the eyelids. Quell is designed to reinforce the tear film’s oil layer to help reduce moisture loss, and that’s a job for the formula as a whole rather than any one ingredient.

Glycerin eye drops preservative free: check the inactive list

“Glycerin eye drops” describes the active ingredient, not whether the bottle has a preservative. That answer is in the inactive ingredients. Quell’s are Caprylyl Glycol, Dead Sea Salt (Sodium Chloride), Emu Oil, Glyceryl Laurate, Glyceryl Undecylenate, Manuka Honey, Polaxamer 188, Sterile Water, Terminalia Chubula and Tromethamine. There’s no preservative among them, which is why the label’s handling line matters every time you open the bottle: Do not touch tip of bottle to any surface to avoid contamination. Read what preservative-free means for more.

How to compare glycerin eye drops on a label

• Look for glycerin, glycerine or glycerol in the active ingredients, with its strength in parentheses.
• Check the purpose column; for these it will usually read “lubricant.”
• Read the Uses line to see what the product is labeled for.
• Compare the other actives. Some drops pair glycerin with other demulcents or with an oil.
• Read the inactive ingredients, including whether there’s a preservative.
• Check the warnings. Quell’s say: Caution should be used in those with egg or bird allergies — For use in the eyes only.

Strength numbers are only comparable between the same ingredient in different products. Our guide to label percentages explains why.

Ingredient names also matter if you keep a list of things to avoid. A list that says “glycerin” should be checked against labels that say “glycerol,” and the reverse. On Quell’s panel, the allergy caution in the warnings concerns egg or bird allergies, which relates to the emu oil among its inactive ingredients rather than to glycerol. When a label uses a name you don’t recognize, a pharmacist can match it to the one on your list.

Is glycerin in eye drops right for you?

A label can tell you what’s in the bottle and what it’s for, but not whether it suits your eyes. Questions about contact lenses, children or using it with other eye drops aren’t covered on Quell’s label; ask your eye doctor or pharmacist. Searches about side effects are worth taking to a pharmacist too, who can go through the full panel with you.

If you use the drop and something feels wrong, the label tells you what to do: Stop use and ask a doctor if you feel eye pain or changes in your vision, if irritation or redness continues, or if the condition worsens or persists for 72 hours. The complete panel is on our Drug Facts page, and the glycerol guide covers the ingredient’s place in Quell.