Lash and brow serums have been game changers in my personal beauty routine. As someone with blonde lashes, I felt like I always had to rely on mascara to look like I even had any lashes at all. That is, until I started using eyelash serums. These formulas made my lashes look longer, thicker and darker. A triple win in one easy step. However, when I found out a common ingredient in many of these serums called prostaglandins was one that could possibly cause my eye color to change—I love my hazel eyes!—it made me second-guess everything.
What are prostaglandins?
According to board-certified ophthalmologist Dr. Diane Hilal-Campo, founder of twenty/twenty beauty, prostaglandins are a group of lipids derived from arachidonic acid. “They are hormone-like substances that are naturally made by our bodies and found throughout every tissue in the body. The effect of a given prostaglandin on the tissue is determined by the type of receptor to which the prostaglandin binds. A given prostaglandin may inhibit a reaction in one tissue and stimulate one in another. Our body produces a variety of different prostaglandins that offer unique functions, from promoting healing to triggering the uterine contractions that cause menstrual cramps.”
Why are prostaglandins in eyelash serums?
One type of prostaglandin called bimatoprost is a medication used for the treatment of glaucoma. “However, when people noticed the side effect of longer lashes from using their glaucoma medication, the pharmaceutical industry seized this opportunity to turn this eye-saving medication into a beauty treatment,” says Dr. Hilal-Campo.
Are prostaglandins regulated by the FDA?
Yes and no. Some synthetic, laboratory-made prostaglandin analogs (PGA) are FDA-approved for medical use and require a doctor to prescribe them. “One example is bimatoprost, a synthetic analog of prostaglandin PGF2 alpha, which binds to the FP receptor,” explains Dr. Hilal-Campo. “It’s also the active ingredient in Latisse, which is used to grow eyelashes. Bimatoprost is under FDA regulation, so you cannot get Latisse without a doctor’s prescription and monitoring.”
You may have heard of isopropyl cloprostenate, which is available over-the-counter and not approved by the FDA or under its regulation. “This is another laboratory-made prostaglandin analog of PGF2 alpha, which binds to the exact same FP receptor as bimatoprost,” Dr. Hilal-Campo says.
There are known risks associated with using both types, regulated or not. However, those “prostaglandin analogues that are not reviewed by the FDA may be riskier because we don’t know their severity,” Dr. Hilal-Campo says, noting that some risks are damaging to the eye structures and are permanent. “Doctors know the side effects of bimatoprost because we have been prescribing the eyedrops for glaucoma for 30 years. And when we prescribe Latisse for eyelash growth, we know the side effects and to watch for them.”
What are the side effects of using products with prostaglandins?
When it comes to using lash serums with PGA of PGF2 alpha, Dr. Hilal-Campo says short-term side effects include irritation and redness of the skin around the eyes, as well as the ocular surface. “Allergic reaction and red eyes are also possible side effects that are reversible when use of the serum is stopped.”
Long-term side effects may include skin discoloration around the eyes. Prostaglandins have also been linked to changing the color of the iris, which can be permanent. This is perhaps one of the biggest detractors for people when choosing whether or not to use an eyelash serum. “Other long-term side effects include damage to the meibomian glands, causing permanent dry eye, as well as periorbital fat atrophy, resulting in a sunken eye with a deepened upper lid sulcus,” says Dr. Hilal-Campo.
Experts also recommend avoiding the use of products containing prostaglandins during pregnancy. “They can cause uterine contraction, so they should be avoided during pregnancy,” Dr. Hilal-Campo advises. One popular alternative ingredient used in eyelash serums is castor oil, and although it’s a natural ingredient, Dr. Hilal-Campo says it too can potentially cause uterine contraction. Therefore, she does not recommend using castor oil–based lash serums during pregnancy either.
Lash Serums Without Prostaglandins
Benefit Cosmetics Whoop Lash ($52)
“Whoop Lash delivers lashes that look healthier and more volumized in as little as six weeks without the use of prostaglandin or its derivatives,” says Autumn Estelle, Benefit’s national brow and beauty authority. “I like to apply a healthy coat to both my top and bottom lashes during my nighttime routine, using the applicator to disperse the product followed by clean fingers to gently press/massage it into both the skin and lashes. This lash serum will make you fall in love with your lashes again—with and without mascara! It quickly it improves the health of your lashes, making them look naturally more thick and full!”
twenty/twenty beauty Get Growing Lash + Brow Serum ($52)
“My lash serum features castor oil, a natural plant oil rich in the fatty acid ricinoleic acid,” says Dr. Hilal-Campo. “Ricinoleic acid is not an analog of PGF2 alpha and has been proven not to bind to the same FP receptors that cause the unwanted side effects of the prostaglandin analogs. Instead, it binds to another receptor, the EP3 receptor, increasing blood supply to the roots of the lashes and causing lash growth. Castor oil is also anti-inflammatory and has been shown to be an effective treatment for blepharitis—inflammation of the lash line—which can inhibit lash growth.”
Vegamour GRO Lash Serum ($72)
The brand’s best-selling serum is 100%-percent vegan, free of prostaglandins and made with plant actives. In clinical studies, it was shown to deliver “visibly thicker, fuller and more luxurious eyelashes in as soon as 30 days.” The serum is also oil-free, so it can be used while wearing lash extensions.
