The other day my friend, who’s getting married in the autumn, mentioned among the group that she might want to invest in an eyelash serum in the months leading up to her wedding. I was quiet; a few others in the room responded with hesitation. The topic of lash growth products, once as much of a no-brainer to recommend as a whitening toothpaste, wasn't met with nearly as much enthusiasm as it would have been just two years ago.
Personally, I quit lash serums in the summer of 2021. After using a popular lash serum twice a day for about a month, my eyelashes were long and black — which is wild in hindsight, considering they’re naturally red in colour. But just as I was enjoying not wearing mascara and my mum commented on my “gorgeous eyelashes” more than three times in one visit, I developed a stye on the inner corner of my lower left lash line (say that three times fast). The stye then became infected and I developed a lump of scar tissue under my eye. I saw an eye doctor, who then referred me to an eye surgeon to have the stye lasered off. Over a year later, the oil production in my left eye is still not back to normal. While my ophthalmologist said that eye infections can happen for numerous different reasons (he was confident mine was entirely stress-related), I felt certain that the eyelash serum was at least partially to blame.
Of course, testing beauty products is almost like an occupational hazard. There are a lot of eyelash serums out there and people want to know how they work; it’s our job to try them and report back. But when we polled the R29 office asking if anyone wanted to volunteer to try a new eyelash serum (and get a sample for free), it was crickets in the Google Chat. I expected at least a handful to be seduced into longer lashes sans mascara, but for various reasons — low bandwidth, sensitive eyes, contacts wearer, truly no interest — almost everyone I asked opted out of testing.
I then messaged my friend, who is also a beauty editor, because she’s reported on “the best eyelash serums” in the past. I asked if she was using any currently. “I am definitely one of the people who are scared of eyelash serums,” she admitted. “I have green eyes and I’m terrified of discolouration, so I steer clear. It’s just such a delicate area in general and I’m not that concerned with having long lashes, so it never seemed super worth it to me.”
Dry eyes, styes caused by the clogging of oil glands (what I believe happened to me), lash line and eyelid hyperpigmentation, and uncontrollable lash overgrowth: These are some of the most commonly cited side effects of eyelash serums. Ophthalmologist Ashley Brissette, says that all of these reactions can be tied back to a particular ingredient in lash serums, both prescription and over-the-counter options: prostaglandins, a group of lipids occurring naturally in humans and other animals that were first used in the treatment of glaucoma.
As the story goes, scientists noted extreme lash growth as a side effect of the glaucoma medication, and prostaglandin was co-opted for cosmetic use. It works — sometimes too well.
“Prostaglandin is really what works to make your eyelashes grow long,” explains Dr Brissette. Essentially, the ingredient extends the anagen phase (active phase) of the lash growth cycle to make the lashes grow longer, increases the size of the base of the hair (called the bulb) so the lashes appear thicker, and stimulates the production of melanin so the lashes appear darker. (Research suggests that same pigment production can also cause hyperpigmentation around the eyes and pigment on the iris, as Behron mentioned.) “Companies...put prostaglandin into lash serum, but it's truly borrowed from medicine,” Dr Brissette says.
With the cosmetic use of prostaglandin, which is found at a lower concentration in an eyelash serum as compared to glaucoma eye drops, noticeable lash growth is definitely a byproduct, but it’s not always glamorous. Optometrist Inna Lazar says she tried a prescription lash growth serum years ago when it was new to the market and it caused her to develop uncomfortable, “bushy” eyelashes. “My lashes were long, but they were very bushy and all over the place,” she says. “Plus I got hyperpigmentation on my lashline. With those side effects, I stopped using it.”
In fact, Dr Lazar notes that many of her glaucoma patients actually consider their longer, thicker, darker eyelashes (a side effect of their prostaglandin medication) to be annoying. “My male patients come in and I have to trim their lashes because they twist, touch their glasses, and get into the eyeball,” she says. For glaucoma patients, Dr Lazar actually has to pluck (she calls it “epilate”) the unwanted lashes. “But for people who have the disease, the side effect is worth it because they're not going blind,” adds Dr Brissette.
Some people say that using a lash serum made their eyes look more tired — something they may have been trying to correct by using the lash serum in the first place.
Of course, we can’t definitively demonise specific lash serums, or even prostaglandin as an ingredient: We might just actually be more tired from lack of sleep. Allergies might be at play, too, while redness and the look of tired eyes can also be caused by staring at your screen too long without blinking (that’s a reminder to blink). But Dr Lazar notes that using prostaglandin-containing eyelash serums on your lash line “certainly doesn't help” these existing conditions and in many cases can exacerbate issues of dryness and irritation, especially if you have ocular rosacea (inflammation which can cause itchiness, burning, and redness in eyes) or sensitive skin. Dr Lazar recently opened a second location specifically to treat dry eye conditions, which have overwhelmed her practice. Many of her patients complaining of “red, irritated eyelids and eyes” use eyelash growth serums.
Kelly Washington, a Refinery29 social editor, has “sensitive and eczema-prone skin” and says that using an eyelash serum caused an overnight reaction around her eyes. “I woke up with puffy, red, sore eyes and big dark circles above and below my eyes,” says Washington. “I was staying with my family at the time and when I came downstairs in the morning, they asked if I was okay due to my appearance. The dark circles were even noticeable on virtual calls.”
I woke up with puffy, red, sore eyes and big dark circles above and below my eyes.
Kelly Washington, Refinery29 Social Editor
In the case of dry eye, redness, hyperpigmentation, or excessive eyelash growth, eye doctors generally advise either discontinuing your prostaglandin-containing serum or cutting down the frequency of use — and consulting your GP. She also recommends switching to a peptide-based lash growth serum, which doesn’t contain prostaglandin. Peptide serums won’t create hair growth by disrupting the natural hair growth cycle, but will nourish and condition the hair and follicles instead.
When testing The Ordinary Multi-Peptide Lash and Brow Serum last summer, R29 editor Karina Hoshikawa noted that her lashes seemed to be growing not longer but definitely healthier with the help of the peptide serum. “I love how my lashes look already and mainly want a product to keep them healthy and strong,” she explained in her product review, adding that she’s more minimalist when it comes to eye makeup, a common theme among our chronically online team. “I don't wear mascara daily, and I am extremely careful with removing eye makeup at the end of the day. I feel like I noticed less fallout while using the serum, which is a great sign.”
If you ask optometrists which eyelash serums are worth it, they’ll likely recommend something formulated by an eye doctor or a company that specialises in the eye area.
If you prefer the perceptible effect of lash serums with prostaglandin included and you’re not experiencing any sort of reaction, keep on keeping on. To get the most out of it, Nicola Alexander-Cross, optometrist and co-founder of Peep Club, recommends using prostaglandin-containing serums for three months, followed by a break of several months to minimise the risk of side effects from long-term use.
The best way to use [lash serums] is only for three months a year and then take a break.
Nicola Alexander-Cross, optometrist and co-founder of Peep Club
Of course, there is no judgment here and everyone’s ingredient tolerance is different. But there is a documented potential side effect that deters a lot of people from using lash serums for longer than, say, the three months leading up to a wedding or big event. It’s called orbital fat loss, and it’s a degradation of the fat volume around the eye, which studies confirm occurs among glaucoma patients with sustained use of prostaglandin medication.
“The fat behind the eyes starts to atrophy and that gives a hollow, sunken-in appearance to your eyes as you get older — it’s a known side effect of those compounds,” Dr Brissette explains. Though there are no studies conclusively confirming evidence of orbital fat volume loss from the specific use of prostaglandin-containing eyelash serums, many doctors posit that it’s possible, even likely, given the glaucoma findings. “If my patients don't want to give up lash serum and I tell them that, most of them stop,” says Dr Brissette.
Unsurprisingly, many people on the internet cite the risk of potential fat loss around their eyes as the foremost reason they forego using eyelash serum. If you type “lash serum side effects” into your TikTok search bar, you’ll be met with a grid of videos with big X's over eyelash serums with both doctors and creators spreading the same message with bold captions about “orbital fat loss.”
But this issue is not as cut and dry as a 30-second TikTok would lead you to believe. We need more conclusive research on the long-term side effects of prostaglandin as used in eyelash serums. Most technologies are just 10-15 years old, so we don’t have long-term data. Plus, if a lash serum is approved by the TGA, you can be assured it has gone through both clinical and safety testing to be verified safe for consumer use. It’s an important note because there are people who truly benefit from these products: those who have lost their eyelashes due to health reasons.
I'd use individual lashes before I’d rely on a serum.
Breanna Davis, Refinery29 Social Editor
All things considered, many people who have used lash serums for aesthetic purposes in the past are now opting for alternative high-maintenance-to-be-low-maintenance treatments with fewer risks associated. According to Google Trends data, search for “lash lifts” has increased over the past year, with many people seeking out the professional service. The service involves sitting with your eyes closed for about 30-45 minutes while a chemical solution is painted over your closed eyelashes, which are held in a curl with the help of a tiny flexi rod. After processing, the solution is rinsed off, the flexi rod removed, and the natural lash curl remains intact for about three to six months. (I’m a huge fan of the lash lift and recommended it to my friend before her wedding.)
One could argue that the attitude towards our eyelashes has become more natural in general. However, that only speaks to a certain aesthetic. For the people who want super long, thick lashes, an expensive eyelash growth serum doesn’t seem effective given the alternatives. “I'd use individual lashes before I’d rely on a serum,” offers Refinery29 social editor Breanna Davis. “I don't have to sit and watch for the results like I would with a serum. Plus, serums don't 100% guarantee significant lash growth for everyone — but simply buying lashes and putting them on does.” She adds there’s a cost factor to the equation, too: “It's less expensive than the ‘99% promised growth’ brands.”
With the price of a small tube of eyelash serum being upward of $50, and our relationship with our eyelashes slowly but surely shifting on its own, it seems that many of us have reexamined the investment — and the potential risks of putting anything that close to our eyeballs on a regular basis.
The information in this article is general in nature. For individual medical advice, consult a healthcare professional.