When a popular eyelash growth serum was first launched in Singapore years ago, my eyelash-loving colleague who regularly wore falsies and eyelash extensions, was beyond excited. She had seen testimonials claiming it could grow longer, denser lashes and was eager to try it.

But just a few months later, she came to me with a different story. Several of her customers who had used the serum developed dark circles around their eyes, alongside their new lash growth. She was shocked and relieved she hadn’t tried it herself yet.

Well, what’s happening? What was in this lash serum that caused such a dramatic side effect?

The answer: bimatoprost, a synthetic prostaglandin hormone. And it turns out, this wasn’t an isolated issue. Many popular lash serums—both prescription and over-the-counter—contain prostaglandin analogues, which can cause more harm than good.

If you care about lash health and eye safety, it’s worth knowing what really goes into your eyelash serum and what to avoid.

Side effects of prostaglandin lash serums 

Many eyelash serums on the market, including prescription ones, contain bimatoprost, a prostaglandin analog originally developed to treat glaucoma. While it effectively stimulates lash growth, it also carries several potential side effects:

• Darkening of the skin around the eyes
• Eyelid inflammation
• Burning, stinging, and eye pain
• Darkening of the iris
• Blurred vision
• Drooping eyelids

These symptoms can arise due to the hormone’s ability to alter pigmentation and affect glandular function in the eye area. While you may achieve longer lashes, you could also be compromising your eye health.

With this understanding of prostaglandin, I've therefore always been cautious when presented with fast growing eyelash serums. I'd research and fully ensure that they are safe, before even testing their efficacy.

Common synthetic prostaglandins in over-the-counter lash serums - you must be aware of

Is bimatoprost the only prostaglandin (hormones) you need to be wary of? No!

Even non-prescription lash serums can contain synthetic prostaglandins or their analogues. These ingredients often fly under the radar because they’re listed under complex chemical names. Be cautious of these common prostaglandin-like ingredients:

·      Isopropyl Cloprostenate

·      Isopropanol Phenyl-hydroxyl-pentene Dihydroxy-cyclopentyl-heptenate

·      Dechloro Dihydroxy Difluoro Ethylcloprostenolamide

·      Trifluoromethyl Dechloro Ethylprostenolamide

Although these synthetic versions provide speedy lash growth, they also pose risks similar to bimatoprost, including skin discoloration, inflammation, and potential long-term gland damage.

Potential long-term side effects of prostaglandins

According to Optometrist Dr. Jennifer Lyerly, the inflammation caused by prostaglandin analogs can have lasting negative effects on vision quality and overall eye comfort. 

“Every time we blink, the meibomian glands secrete their oil. If that oil is too thick, it's difficult for the eyelids to spread it evenly over the surface of the eye --more like toothpaste than olive oil. It may even get so thick that the oil blocks and backs up in the gland. This will slowly but surely damage the gland permanently. If the meibomian glands atrophy or die off, the body is not able to repair the tissue and the gland becomes permanently nonfunctional. The result is irreversible and often severe dry eye.”

- Dr. Jennifer Lyerly

 Eyelash Serum without prostaglandins (hormones)

Thankfully, not all lash serums are created equal. At an international beauty exhibition, I discovered Cangro Long Lashes, a vegan lash serum from Australia formulated without hormones or prostaglandins.

Cangro’s founders, Felicia and Belinda, created the serum after experiencing side effects from other products. Their goal? A natural, effective solution safe for all, including post-chemotherapy patients and those with sensitive eyes.

Instead of hormones, Cangro Long Lashes uses a blend of peptides, vitamins, and antioxidants to encourage natural lash growth and retention.

Key Ingredients in Cangro Long Lashes:

Cangro’s approach may take a little longer to show results, but it’s worth the wait for a formula that is safe for long-term use and ideal for sensitive eyes.

👉 Curious to see how it works? Explore Cangro Long Lashes here and decide if it’s the safe lash serum you’ve been looking for.

Other nasties you want to avoid in eyelash serums 

Besides prostaglandins, keep an eye out for these harmful or controversial ingredients:

PEGS:  May be contaminated with known carcinogens like 1,4-Dioxane.

Sodium Benzoate + Ascorbic Acid: When combined, can form benzene, a potential carcinogen.

Potassium Sorbate: Known allergen and skin irritant.

Triethanolamine: Damaging to the skin and respiratory system with long-term use. Risks are magnified for the sensitive skin around the eyes.

Boric Acid & Sodium Borate: Linked to endocrine disruption and restricted in some countries.

Final Thoughts: Choose Wisely for Long, Healthy Lashes

Eyelash serums can be a powerful addition to your beauty routine, enhancing both the appearance and health of your lashes. But not all formulas are created equal.

Choosing a hormone-free, prostaglandin-free eyelash serum like Cangro Long Lashes helps you grow longer, healthier lashes safely and naturally, without compromising your eye health or skin.

Your eyes are worth it.

References:

Common and Rare Side Effects for Bimatoprost Ophthalmic (Eye)

Bimatoprost

HORMONES IN YOUR LASH SERUM?

Enhanced Eyelashes - prescription and otc options

The Hidden Dangers of Lash Growth Serums

10 Nasty Ingredients To Avoid In Skincare (And Why)