How Do Lash Growth Serums Work?

If you’ve ever used one of the top lash serums, you already know they work. What’s not so clear is: how do lash growth serums work.

Like so many of the products that promise unbelievable results, lash growth serums work through a combination of strategic ingredients intended to lengthen, thicken, and darken lashes.

The extent to which they fulfill that promise depends on the type of serum, its ingredients, and the additional work you’re willing to put into helping the serum work its magic.

That’s why the answer to “how do lash growth serums work?” is not a straightforward one. We’ll break it down for you in this in-depth answer to that very complicated question. By the end of it, you’ll be a lash serum guru. Promise.

Do Eyelash Growth Serums Actually Work? 

Ah, the ever popular question of whether lash serums actually work. Again, the answer to that question isn’t as black and white as it may seem.

To answer it, you have to understand the difference in the two basic types of lash growth serums: those that actually affect the length of your lashes and those that merely nourish and condition. Here’s a quick recap of both.

Prostaglandin Lash Serums

On the one hand are the lash growth serums that contain active ingredients known as prostaglandins. These compounds are the only compounds known to increase the length and fullness of eyelashes.

If you can find a serum with prostaglandin analogs, you’re pretty much guaranteed to see improvements.

Because prostaglandin analogs lengthen your lash growing cycle, your lashes are given free rein to grow longer, thicker and even darker. The result? Seriously dramatic lash growth.

Lash Conditioners

On the other hand, are the lash serums that are actually conditioners. These contain moisturizing, cell-communicating ingredients that boost the health of your hair, your hair follicles, and the skin along your lash line.

By creating a healthy environment around your lashes, you give them their best chance at growing strong, healthy, long, and full.

The degree to which either of these types of lash serums work is dependent on: 

  • how good the ingredients are
  • the quantities of said ingredients
  • where you’re starting from/the adequacy of your natural lashes

And with that said, where you’re starting from is an important factor. You should have realistic expectations about potential results, be willing to experiment with different brands and products, and try combining multiple treatments at once to strengthen the efficacy of each.

If all else fails, know that there are plenty of alternatives. Most people see great results from the best of the lash conditioners but keep your expectations in check: you won’t see the sort of ridiculous lash growth that prostaglandin-containing lash serums provide.

What you will get, though, are healthier, thicker and longer lashes.

How Do Lash Growth Serums Work?

How your lash serum works, and how well it works for that matter, depends on its ingredients. Below, we’ve listed some of the more common ingredients found in the most effective lash serums – and how they cause lash growth.


The most effective ingredients for lengthening lashes, prostaglandins are often listed as Isopropyl Cloprostenate, Prostaglandin I.C., Dechloro Dihydroxy Difluoro Ethylcloprostenolamide, and Methylamido Dihydro Noralfaprostal (MDN). Its prescription variation is called bimatoprost – that’s the ingredient found in Latisse

Latisse Before and After

Regardless of the name, these compounds work by increasing the anagen (growth) phase of your lash lifecycle.


These small chains of amino acids work as tiny, cell-communicating messengers.

As amino acids, they nourish and condition, but in their cell communicating capacity, they can stimulate hydration, cell regeneration, and healthier hair follicles.


Every lash serum should include moisturizing ingredients that counteract any potential moisture loss or irritation caused by the serum itself.

Perhaps more importantly, moisturizers keep your lashes and hair follicles hydrated – and that’s the key to a healthy lash line.

Vitamins and Nutrients

Vitamins and nutrients such as vitamin c and e, essential fatty acids, and niacin are important to skin and hair health. But there are also nutrients that directly target your hair, including biotin, keratin, and collagen. 

Natural Oils

Natural oils and plant extracts might be included in a growth serum for any number of reasons. Typically, they’re found in cosmetic formulas for hydrating, conditioning, cleansing, and anti-bacterial properties. 

How to Get the Most Growth from Your Lash Growth Serum

There are a few steps you can take to help your lash serum work its lash-growing magic. Follow these tips to maximize the benefits of any lash serum you use.

Take Care of Your Natural Lashes

Maintain your lash health by using good products. That not only means a good lash serum, but also makeup products that contain skin and hair beneficial ingredients, such as conditioning mascaras. 

Speaking of which, you should consider taking a break from your makeup every so often. That allows your hair to breathe and revitalize naturally.

Another component of taking care of your natural lashes that oh so many of us fail to follow-through on is removing your makeup.

Yes, we get it. Coming home at 3 am and having to wakeup for a bridal shower at 8 am isn’t exactly conducive to taking those 5 extra minutes to wash your face. But it’s absolutely necessary in caring for that important lash line. 

Application Is Key

You should apply your lash serum with the same care as you remove your eye makeup every night before bed (because that’s worth repeating).

Not only is that a practice for caring for your lashes, but your lash serum also can’t stick to eye makeup and mascara, rendering it ineffective before it ever had a chance. 

Dip the applicator supplied into the serum once, wiping off any access on the edges of the bottle. Apply the serum to the root-line of your eye lashes, moving from the inner corner to the outer corner. 

Get as close to the roots as possible. The serum will drip down your lashes as you blink, covering them fully and transferring to the lower lash line as well. Also, remember that less is more, and you need only a thin layer to be effective.

Allow the serum to dry for at least 90 seconds and avoid applying any additional product that may hinder the serum from penetrating your lashes. 

Supplement the Lash Serum

Unless you’re using a serum with prostaglandins in the formula, your serum acts more to improve the health of your lashes than as a guaranteed growth solution. The idea is that, the healthier your lashes are, the more likely they are to grow to their full potential. 

You can help that process along by supplementing the work your serum is doing to create a healthy environment. Consider taking dietary supplements containing lash boosting vitamins and proteins. Or, just try to include these necessary nutrients in your daily diet.

Be Consistent (and Patient)

Of all the advice we can give you for expanding the reach of your lash serum, this is one you’ve got to remember: consistency is everything with lash growth serums. 

While you can throw on layers and layers of the stuff twice per week, you’re not going to notice much in terms of results. But, using a small amount, regularly (as in, every single night), that’s when the magic happens.

So be consistent and, once you’ve achieved your desired results, you can reduce your usage from every evening to a few times per week or every other day.