One small study found that a lash serum made with a prostaglandin analog left the tear film less stable, lowered tear volume and increased eye redness after six weeks of nightly use. That isn’t proof that lash serums cause dry eye. The study followed 19 healthy women, had no comparison group, and tested a single serum with a single ingredient. What it does give you is a reason to read the ingredient list before you buy, because lash serums come in two kinds: those with a prostaglandin analog and those without. If your eyes already run dry or red, the serums without one are the cautious place to start, and an eye doctor is the right person to ask about anything that goes on your lash line every night.
What the researchers did
The study came from a team based mostly at the University of Seville in Spain and was published in the journal Eye & Contact Lens in 2026. Nineteen healthy women applied a lash serum to the upper lash line once a day for six weeks. The serum contained a prostaglandin analog with a very long name: dechloro dihydroxy difluoro ethylcloprostenolamide, often shortened to DDDE.
The team examined each woman’s eyes before she started and again at the end, using an instrument that measures the tear film. That’s the thin layer of tears that coats the front of your eye.
| What they measured | What changed after six weeks |
| Tear film stability (how long the tear film holds together) | Dropped by about four seconds on average |
| Tear volume | Slightly lower on both measures used |
| Eye redness | Up by roughly two percentage points on the outer side of the eye |
| The eyelid glands the team imaged | No significant change |
| Signs of damage to the eye’s surface | No significant change |
The authors concluded that even short-term use may disturb the balance of the eye’s surface and cause mild inflammation. They also said longer studies are needed. They reported no conflicts of interest.
What this study can’t tell us
Quite a lot, and the limits matter more than the headline.
- It was small. Nineteen women. The size of the change also varied widely from one woman to the next.
- It was short. Six weeks. Nobody knows from this whether the changes grow, level off or fade with longer use, or what happens after stopping.
- There was no comparison group. Each woman was compared only with her own starting numbers. Without a second group using a serum that lacks the ingredient, the study can’t separate the prostaglandin analog from the rest of the formula, or from the simple fact of painting a liquid along the lash line every day.
- It tested one serum with one analog. The results don’t automatically carry over to other analogs or other brands. The published summary doesn’t name the product.
- Everyone was healthy. It says nothing about people who already have dry eye or another eye condition.
- The results are instrument readings. A less stable tear film on a machine isn’t the same as a diagnosis of dry eye.
So the fair reading is narrow: in a small group, over a short time, one prostaglandin-analog serum was followed by measurable changes in the tear film and a little more redness. It’s a signal worth knowing about, and it’s far from the last word.
What is a prostaglandin analog?
Prostaglandins are chemical messengers your body makes on its own. An analog is a lab-made molecule built to resemble one closely enough to act in a similar way.
The best-studied one for lashes is bimatoprost, the active ingredient in the prescription lash treatment Latisse. Its FDA-approved label describes it as a prostaglandin analog and says the exact way it works isn’t known. Lashes are believed to grow longer because more of them are in the growth phase at once, and they stay in it for more time. (Here’s how the lash growth cycle works.) The same label lists eye redness, itching and dry eye symptoms among the reactions reported in its clinical trials, each in fewer than 4 in 100 patients.
Some cosmetic lash serums use molecules from the same family. A second paper, from two pharmacy researchers at Nantes Université in France, went looking for them. They checked the formulas of 79 cosmetic products promising longer or fuller lashes and found that about 30% contained a prostaglandin analog. The rest were built on ingredients such as castor oil, amino acids, panthenol and peptides. The authors’ concern is that these analogs aren’t regulated for use in cosmetics.
How to spot one on an ingredient list
The front of the box won’t always tell you, so turn it over. The French paper names four of the six it found:
| Name on the label | Notes |
| Isopropyl cloprostenate | One of the two most common in the 79 products checked |
| Dechloro dihydroxy difluoro ethylcloprostenolamide | The other most common one, and the one in the Seville study. Also called DDDE or ethyl tafluprostamide |
| Bimatoprost | The prescription lash ingredient |
| Norbimatoprost | Also found among the products checked |
The shortcut: all of them have “prost” buried somewhere in the name. If you see those five letters in the middle or at the end of a long chemical word, you’re looking at one. That list isn’t complete, so the absence of these four isn’t a guarantee.
Some brands make it easy. GrandeLASH-MD’s ingredient list reads “Isopropyl Cloprostenate (an analog of prostaglandin),” which is about as clear as labeling gets. And a serum made without one often says “prostaglandin-free” on the box, because it’s a selling point.
Does this mean you should avoid prostaglandin serums?
Not on the strength of 19 women and six weeks. Prostaglandin-analog serums are popular because they tend to give the most visible length, and plenty of people use them without trouble. Our GrandeLASH-MD review lands on “buy” for non-sensitive eyes with a doctor’s okay, and nothing in this study changes that. GrandeLASH-MD uses a different analog from the one the study tested.
What the study adds is one more item for the fine print. Irritation, redness and eyelid darkening were already on the list of things to watch for with this ingredient family. Tear film changes may belong there too. If you use one, apply a thin line to the upper lash line only, keep it out of the eye, and pay attention to how your eyes feel over the first couple of months. If they turn dry, gritty or red, see an eye doctor rather than guessing. They can check your tear film directly.
Lash serums made without a prostaglandin analog
These four are labeled prostaglandin-free by their makers and rely on peptides instead. Expect a subtler result than the analog serums give, and note that nobody has put these through the tear film test either. Prostaglandin-free means one ingredient class is left out. It doesn’t mean a product can’t irritate your eyes.
Grande Cosmetics GrandeLASH-Sensitive
About $48
Prices move constantly, so we link to live listings instead of printing a number that is wrong by the time you read it. Links go to Amazon, which is where a referral gets credited.
ForChics ForLash Eyelash Enhancing Serum is about $26, though the price changes often. It has four peptides, biotin and Panax ginseng, with no prostaglandin analog, and it goes on once a night along the upper lash line. That makes it the simplest routine of the four.
Babe Original Renewing Lash Serum is about $29 for the 3 mL tube. It’s a peptide serum that Babe Original labels prostaglandin-free, applied morning and night just above the upper lash line. The brand sells more than one lash serum, so check that the box says Renewing.
Grande Cosmetics GrandeLASH-Sensitive is about $48. It comes from the maker of GrandeLASH-MD and swaps the prostaglandin analog for a peptide complex, botanicals and vitamins. It goes on twice a day. Grande describes the MD as the faster of the two and this one as its gentlest formula. The brand is renaming it GrandeLASH Peptide+ with the same formula, so you may see either name.
Olaplex LashBond Building Serum is about $68 for 4.5 mL. It’s made without prostaglandins and pairs a peptide complex with hyaluronic acid and biotin. Olaplex’s directions are one swipe along the upper lash line twice a day, then two or three times a week once you’re happy with your lashes.
The Ordinary Multi-Peptide Lash and Brow Serum, the dupe in our GrandeLASH-MD review, contains no prostaglandins either. Our guide to lash serums compares both types side by side.
If I Were You
If your eyes already feel dry, or you’ve been told you have dry eye, start with a prostaglandin-free serum and run it past your eye doctor first.
If you use a prostaglandin serum and your eyes feel fine, this study isn’t a reason to panic. Keep the line thin, keep it on the upper lid, and mention the serum at your next eye exam.
If you use one and your eyes have been red, gritty or tired lately, tell your eye doctor which serum you use and bring the ingredient list. Don’t try to work it out alone.
If you haven’t bought anything yet, decide which matters more to you: the most visible length, or the fewest question marks. Then read the back of the box, not the front.
If you’re pregnant or nursing, ask your doctor before starting any lash serum.
FAQ
Do lash serums cause dry eyes?
Nobody can say that yet. One study of 19 women found a less stable tear film, lower tear volume and more redness after six weeks on a prostaglandin-analog serum. It was too small and too short, and it had no comparison group, so it can’t prove the serum was the cause.
Did the study test serums without a prostaglandin analog?
No. It tested one serum containing one analog. Whether peptide serums affect the tear film hasn’t been measured in this research.
How do I know if my lash serum has a prostaglandin analog?
Read the full ingredient list and look for “prost” inside a long chemical name, such as isopropyl cloprostenate or dechloro dihydroxy difluoro ethylcloprostenolamide. Serums made without one often say “prostaglandin-free” on the box.
Are peptide lash serums safer for your eyes?
They leave out the ingredient family this study looked at, and they have a reputation for being gentler. That isn’t the same as proven safe for everyone. Any product used at the lash line can irritate, so stop if your eyes react.
Is Latisse the same as a cosmetic lash serum?
No. Latisse is a prescription drug containing bimatoprost, with clinical trials and a drug label behind it. Cosmetic serums that use a prostaglandin analog use related molecules and haven’t been through that process.
Bottom line
A small study has linked one prostaglandin-analog lash serum to a less stable tear film and a bit more redness after six weeks. It’s an early finding with real limits, and it applies to one type of lash serum, not all of them. Learn to spot “prost” on the ingredient list so the choice is yours, and let an eye doctor weigh in if your eyes are dry or irritated. For what to do with those lashes afterward, there’s more in our lash and brow care routine and the makeup archive.
