If you want to know exactly how long it takes for a lash serum to work, you’re at the right place. I’ve summarized clinical trial data to find out the science behind it. I’ve also looked at the results for some of the most popular eyelash growth serums on the market.

I wanted this article to be the most comprehensive resource on the web to answer the infamous question of “how long do lash serums take to work?”. For that reason, I decided to research this question thoroughly from 3 angles:

1. What lash serum brands say
2. What clinical trials say
3. What people using lash serums say

Let’s dive in!

How Long Does Lash Serum Take To Work?

Now, each eyelash growth serum company reports slightly different results on their website for the time it takes their product to work.

Why is that?

Mostly because they all have different ingredients and proportions that can influence the speed at which you can start seeing results. For instance, some brands will use prostaglandin analogs which are known to produce quicker results than other ingredients (but also come with possible side effects).

Also, let’s be honest, there are probably some marketing strategies at play.

To make things easier, I decided to compile a list of some of the most popular lash serum brands and how long they say their serum takes to work.

How Long Lash Serums Take To Work According to the Brands

Eyelash Growth Serum	How Long it Takes	Source
Dime Lash Boost Serum	8 Weeks	https://dimebeautyco.com/products/eyelash-boost-serum
GrandeLASH™ Lash Enhancing Serum	16 weeks	https://grandecosmetics.com/products/grandelash-md
Rodan And Fields Lash Boost	4 Weeks	https://www.rodanandfields.com/en-us/images/archives/ENHANCEMENTS_Lash_Boost_FAQs.pdf
Mary Kay® Lash & Brow Building Serum™	4 Weeks	https://www.marykay.ie/en-ie/products/makeup/eyes/mascara-lashes/mary-kay-lash-brow-building-serum-130108
Babe Lash Essential Serum	12 Weeks	https://www.babeoriginal.com/products/essential-eyelash-serum
E.L.F Enhancing Lash & Brow Serum	n/a	n/a
Rapidlash Serum	8 Weeks	https://rapidlash.com/pages/q-a
Monat Lash & Brow Enhancing Serum	4 Weeks	https://monatglobal.com/ca/eye-wonder-lash-brow-enhancing-serum/

As you can see, there’s quite a disparity between brands.

The thing is, all these brands are likely telling the truth about their product. Unfortunately, there’s no universal standard on what “works” means for a lash serum.

For example, does it mean:

• Your lashes grew by 1 mm, 1.5 mm, or 2 mm?
• You have X more eyelashes?
• Your eyelashes are more dense and voluminous? If so, how do you measure it?

As you can see, it’s hard to have a common benchmark that all brands would agree upon.

Having said that, we can make the general assumption that brands using an active ingredient such as prostaglandin analogs, will have quicker results. This ingredient has been proven effective in clinical trials to stimulate lash growth.

But all is not rainbows and unicorns. These ingredients have possible side effects you must know about.

Let’s check out the clinical trials next.

How Long Lash Serums Take To Work According to the Clinical Trials

Brands can make claims, but at the end of the day, what really matters is if there’s any scientific evidence to back up those claims.

Unfortunately, when it comes to lash growth serums, there are not a lot of high-quality studies. I did manage to find two clinical trials that looked at the efficacy of lash serums:

1. Latisse clinical trials.
2. MS Clinical Research clinical trials.

Let’s look at each one in detail.

Latisse Clinical Trials

The first clinical trial I want to talk about is the one done by Allergan, the maker of Latisse.

Latisse is the only FDA-approved lash serum on the market today. This product is marketed as a treatment for hypotrichosis, which is the loss of eyelashes.

The active ingredient that can be found in Latisse is called “Bimatoprost” which is part of the prostaglandin class of drugs.

You can find the clinical review data from the FDA’s website right here.¹

Here’s what they did:

• Evaluate the efficacy of bimatoprost 0.03% in promoting the growth of eyelashes.
• Subjects were instructed to apply the solution once per day on the upper eyelid.
• The study consisted of 8 visits over the course of 4 months with one post-treatment follow-up at month 5.
• The lash growth was accessed using the GEA scale (1=none or minimal eyelash prominence; 2=moderate eyelash prominence; 3=marked eyelash prominence; 4=very marked eyelash prominence).

Results:

• After 16 weeks, 78% of subjects in the bimatoprost 0.03% group had at least GEA 1-Grade increase compared to 18% in the vehicle group.
• After 20 weeks, 79% of subjects in the bimatoprost 0.03% group had at least GEA 1-Grade increase compared to 21% in the vehicle group.
• After 16 weeks, 32.8% of subjects in the bimatoprost 0.03% group had at least GEA 2-Grade increase compared to 1.4% in the vehicle group.
• After 20 weeks, 37.4% of subjects in the bimatoprost 0.03% group had at least GEA 2-Grade increase compared to 3.2% in the vehicle group.

So what can we conclude from these results?

The study found that the lash growth was significantly greater in the bimatoprost 0.03% group compared to the vehicle group.

Having said that, there were also adverse events (side effects) reported in the study. The most common side effects were erythema (redness), pruritus (itching), and skin hyperpigmentation (darkening).

It is important to note that Latisse is a prescription medication and should only be used under the supervision of a healthcare professional.

Wait, what about all the other lash growth serums on the market?

Indeed. Although Latisse is the only FDA-approved eyelash growth serum using a prostaglandin analog active ingredient (Bimatoprost 0.03%), there are other products on the market using prostaglandin analog ingredients!

And these growth serums are not FDA-approved which means there’s less data for consumers to make a wise decision.

But that’s for another time… I’ll probably write an article about it at some point.

MS Clinical Research Clinical Trials

The next clinical trial worth discussing was done by MS Clinical Research.

You can find the study and results here.²

Here’s what they did:

• Subjects were 30 women, aged 18-45, hoping for better and fuller eyelashes.
• Each participant was asked to apply the serum at the margins of both eyelids evenly and in the same way to eliminate any room for error.
• Participants were instructed to apply the serum once every night for 90 days.
• Participants revisited the center for observations by dermatologists after 30, 60, and 90 days.

Results:

• Following 30 days of utilizing a polygrowth factor serum, subjects experienced the following improvements: lash length increased by 10.52%, volume improved by 9.3%, and thickness improved by 35%.

How Long Lash Serums Take To Work According to Real People

Testimonials from real people are normally more valuable than anything else. It gives you a better sense of what to expect and how other people reacted to the serums.

That’s why I like Youtube.

There are tons of videos of people trying and reviewing different lash serums. So, I went ahead and compiled the 3 most popular ones I could find.

1- LashBoost + RapidLash Review | 1 Month Results

In this video, several women try 2 eyelash growth serums for 30 days and document their journey.

All of them have different lashes to begin with but they all end up with pretty amazing results.

What I love about this video is that they were instructed to apply two different serums, one on each eye! That way, they can easily compare which one works best.

Check it out!

2- GrandeLASH Review | 3 Months Results

Here, on youtube, Monica Esparza shares with us her results after using the Grande Lash MD Lash Enhancing Serum for 3 months.

Spoiler alert: she loved it!

3- Maxey Lash Serum Review | 1 Month Results

Lainey Marie shares with us her amazing results using the Maxey Lash serum. She started noticing results after 4 weeks.

Make sure to watch this great video!

FAQs

References

1. FDA (2008). Clinical Review Latisse (bimatoprost ophthalmic solution 0.03%). Retrieved from https://www.accessdata.fda.gov/drugsatfda_docs/nda/2008/022369s000_MedR.pdf [Accessed 19th June 2022].
2. Mukta Sachdev, Keerthi Velugotla,  Sapna Revanker, and Geetha Somasekhar. (2020). An Open-label, Single-center, Safety and Efficacy Study of Eyelash Polygrowth Factor Serum. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7158911/ [Accessed 19th June 2022].