Eyelash-Growth Serum: what Works, what Doesnt

Curated by Claudia Shannon / Research Scientist / Honayst

Eyelash-growth serum is one of those beauty products that seems too good to be true. Is it really possible to make your eyelashes grow thicker and longer, ostensibly removing your need for temporary lash-lengthening options, like mascara and false eyelashes?

But do these serums really work? And if they do, which is the best eyelash- growth serum out there? And is it safe to use so close to your precious eyes? We talked to the pros to find out.

First, let’s review the way eyelashes grow normally.

Just like any of the hairs on the scalp, eyelashes follow a specific growth pattern. “There are three phases to eyelash growth: the anagen (active), catagen (transition), and telogen (resting),” optometrist Pamela A. Lowe, O.D., tells Honayst.

During the anagen stage, the lash is constantly growing. This phase can last between four and six weeks. During the catagen phase, eyelashes are at their maximum length and the hair follicles begin to shrink. This part of the cycle can last from two to three weeks, Lowe says. The last part of the cycle is the telogen phase. It’s the resting period and can last approximately 100 days before the lash naturally falls out. “Each individual lash undergoes a phase at different times,” Lowe says. “On average, replacement of a single lash is anywhere from four to eight months.”

Here’s how over-the-counter eyelash-growth serums supposedly work.

The truth is, most of the eyelash-growth serums you see in stores won’t do anything. But for the sake of understanding what’s in them, here are the ingredients they most often tout: Biotin: This is the most common active ingredient in over-the-counter eyelash- growth serums, which are often marketed as conditioning treatments. Biotin is a B vitamin, and it is said to improve hair’s health by strengthening keratin, the protein that makes up hair.

Unfortunately, “the influence of biotin on hair and nail growth is closer to urban myth than a fact at this point,” cosmetic chemist Stephen Alain Ko tells Honayst. Lowe agrees and says that the same is true when it comes to your eyelashes. “There is no compelling evidence that biotin will increase lash growth. And because many supplements of biotin rarely get absorbed into one’s system efficiently—unless one is extremely deficient—it really doesn’t pay off to use it for this purpose.”

Castor Oil: You’ve probably also read about using castor oil as a DIY lash- growth serum. But while hacks with this and other oils can make your eyelashes look longer, it’s probably just a trick of the eye, not legit growth. “What may be occurring is that the glossing and coating effect of oils can give the illusion that hairs are thicker. And it may also prevent breakage,” Ko says. But that’s about the end of the benefits.

Peptides, panthenol, and hyaluronic acid: Other eyelash serums include a cocktail of these ingredients, but the effects, if any, are very subtle. “Most of these act as water binders or moisturizers,” says Ko. “They can increase the flexibility of the hair (reducing fracturing and breakage) or even coat them to make them look thicker.” But he says there isn’t proof that they can actually increase hair growth.

Are eyelash-growth serums safe?

If you choose to try serums to enhance the look of your lashes, you have to be careful about how you apply them. Most serum instructions say to apply the product close to the root, but you need to be careful since it can be tough to avoid getting products on your skin or in the eye. “Also, the gland openings on the eyelids that are essential for proper tear function can potentially become clogged, thereby causing discomfort, styes, and infection,” Dr. Lowe says.

The easiest way to apply serums is to use the included applicator, starting on the inner corner working toward the outside. And use the hand on the same side as the eye you’re working on, so your view isn’t obstructed. With any beauty treatments, it’s always best to check with your doctor to find out what’s ideal for you. They’ll help you find the best eyelash-growth serum for you.

This is the one eyelash-growth serum that’s proven to work.

In order for a lash serum to really make a difference, it has to affect the growth cycle of the hair. And only one is proven to do that: Latisse, which is the only FDA-approved treatment proven to make eyelashes grow. It can extend the anagen growth phase, and it is actually effective.

The treatment’s key ingredient, bimatoprost, started out in glaucoma medicine to reduce pressure against the eye, Ko explains. Patients noticed that one of the side effects from using bimatoprost was longer, thicker eyelashes. And that’s how the cosmetic benefits were discovered.

But since the treatment is a pharmaceutical drug, the only way you can get your hands on it is with a doctor’s prescription. In fact, it contains the same active ingredient as Lumigen, an eye-drop medication used to treat glaucoma.

Though effective, it comes with some caveats. You need to faithfully apply it every night before bed, and be sure to do so right at the lash line. “Hair is dead, and applying things to the shaft’s ends won’t have any effect on growth (beyond preventing breakage),” Ko explains. It can take months to notice any results. And be forewarned: One of the side effects of bimatoprost is discoloration on the eyelids and the iris.

Try these eyelash-growth serums—but remember that your mileage may vary.

Because over-the-counter beauty and skin-care products aren’t regulated like drugs, you can’t necessarily trust the claims they make. So when you’re looking for an eyelash-growth serum that works, know that you may have to adjust your expectations. Here are a few of the best over-the-counter eyelash-growth serums available, based on their conditioning, moisturizing ingredients.

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