Lash Serums Explained: What Works, What’s Risky, and What to Avoid
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So, I think one of the questions I get most often from my female patients—and one they almost seem embarrassed to ask—is about lash serums.
They’ll say it quietly, almost apologetically:
“This isn’t a serious question, but... can I use a lash serum?”
Let me tell you—I’m always glad when patients ask. Because while longer lashes might seem like a cosmetic concern, lash serums can actually have real effects on your eyes. And as your ophthalmologist, I need to know what you’re using around them.
And, full disclosure, I’m a former lash serum user myself. Years ago, I used both Latisse and Rodan + Fields Lash Boost—and yes, they worked. My lashes looked amazing. But I also learned firsthand about some of the side effects we’ll talk about today.
The Three Types of Lash Serums
Not all lash serums are created equal. Most fall into one of three categories:
Prostaglandin-based serums (like Latisse, GrandeLash, and Lash Boost)
Peptide-based serums
Vitamin or botanical “conditioning” serums
Let’s break down what that actually means.
1. Prostaglandin Lash Serums
This is the most powerful—and most studied—type.
The first lash serum, Latisse, started out as a glaucoma medication called bimatoprost. Eye doctors noticed that patients treated in one eye for glaucoma started growing longer lashes on that eye.
So, a smart ophthalmologist decided to repackage it—and voilà, Latisse was born.
Latisse is FDA-approved and clinically proven to grow lashes by keeping them longer in the “growth” phase of the lash cycle. But it comes with side effects.
Over-the-counter versions (like GrandeLash or Lash Boost) use synthetic prostaglandin analogs such as isopropyl cloprostenate. These mimic Latisse’s ingredient but are not regulated or studied as thoroughly.
And that’s where problems can arise.
2. Peptide Lash Serums
Peptide serums use amino acid chains—like tripeptides or octapeptides—to strengthen and condition lashes.
They’re marketed to “nourish” the lash follicle by stimulating keratin, but here’s the thing: there are no randomized clinical trials proving they actually make lashes grow.
They’re likely safe, but their effectiveness is mostly anecdotal.
3. Vitamin or Botanical Lash Serums
These are the ones that contain things like biotin, panthenol, castor oil, or vitamin E.
They don’t technically grow lashes, but they can help condition and hydrate them—similar to how Vaseline makes lashes look thicker.
Think of them as “lash conditioners,” not “lash growers.”
What the Research Shows
Latisse remains the gold standard, with studies showing:
78% of users had visible lash lengthening
Maximum results appeared around 16 weeks
Most people were satisfied with the results
For the other types of serums? There’s little to no scientific data backing their claims.
The Side Effects You Should Know
Here’s where things get important. The same prostaglandin compounds that make lashes longer can also cause real changes around the eyes.
Common Side Effects:
Redness and irritation
Dryness or burning
Blocked oil glands at the lash line
Cosmetic Side Effects:
Skin darkening under the eyes (I experienced this one myself)
Loss of fat around the eyes, making them look sunken—and this one can be permanent
Eye color change, especially for hazel or green eyes (they can darken and stay that way)
Those are not risks most people associate with something they bought at Sephora.
Even though these effects are rare, they’re not zero—and some are irreversible. So it’s really about deciding whether the aesthetic benefit is worth the potential risk.
What to Ask Your Eye Doctor
If you’re using (or considering) a lash serum, bring it up at your next eye exam. It’s not trivial—we want to know.
Here are a few questions to ask:
Is this safe for my eyes?
(Certain conditions—like glaucoma, uveitis, or dry eye—make lash serums riskier.)Do you see any signs of side effects?
(Your doctor can check for redness, blocked glands, or subtle changes in your eye anatomy.)Are there safer alternatives?
(Sometimes a peptide or conditioning serum may be better suited for you.)
My Personal Take
As much as I loved the way my lashes looked, the dark circles and risk of fat atrophy weren’t worth it to me.
These days, I stick with gentle conditioning serums—castor oil, vitamin E, and biotin-based formulas. They don’t transform your lashes overnight, but they’re safer and keep them healthy.
And remember: “natural” doesn’t always mean “safe.” You can still have allergic reactions to plant-based ingredients, so always patch-test and stop if you notice irritation.
Bottom Line
Lash serums do work—but the ones that really grow lashes can also have real medical side effects.
Before you reach for a product promising “clinically proven results,” check the ingredient list. Look for bimatoprost or isopropyl cloprostenate—and think twice before using anything that contains them without talking to your eye doctor first.
Because your lashes might look better—but your eyes deserve to stay healthy, too. 💕
Want to Learn More?
This is just the beginning. In upcoming episodes, we’ll explore:
-How screen time and digital habits are shaping our kids’ development
–The connection between vision and overall health
–What you need to know about common eye procedures like LASIK and cataract surgery
–Practical ways to advocate for your child’s visual needs
You can subscribe to my podcast, In Focus, anywhere you listen—or follow along on Instagram for updates and tips.
Watch this episode on Youtube right now!
Thanks for reading—and for doing what you can to protect your child’s vision, one step at a time.
– Dr. Rupa Wong
Pediatric Ophthalmologist | Surgeon | Mom of 3
This episode is brought to you by The Pinnacle Podcast Network! Learn more about Pinnacle at learnatpinnacle.com
