Do Lash Serums Work? The Short Answer on Getting Long Lashes

Many people with short eyelashes wish for longer, fuller lashes without having to use mascara. Using a lash serum sounds appealing, but how well do they actually work? According to Diane Hilal-Campo, MD, a board-certified ophthalmologist and the founder of twenty/twenty beauty, the effectiveness of lash serums can vary from person to person and brand to brand.

“Lash serums can work in different ways, depending on the ingredients. Some lash serums work by altering the hair growth cycle,” Dr. Hilal-Campo says. The hair growth cycle has three phases—anagen, catagen, and telogen.

• Anagen is the phase during which hair grows.
• Catagen is the transition phase when the hair stops growing, and the follicle begins to shrink in preparation for the final phase.
• Telogen, or resting phase, is when the hair is dormant and begins to loosen until it falls out.

“On average, this entire cycle takes about four months,” Dr. Hilal-Campo explains. The anagen phase lasts about a month, with the longest phase being the resting phase. “When using a lash serum, the anagen phase is extended, giving lashes a longer amount of time to grow.”

Some people may see noticeable improvements in both the length and thickness of their lashes with regular use, while others may not see significant results. It's important to have realistic expectations, as visible changes may take several weeks to months to appear.

Understanding what makes a lash serum effective, the difference between prescription and over-the-counter (OTC) options, and the best time of day to use eyelash serums can help you choose the right product for your needs.

What are lash serums?

Lash growth serums are specially formulated treatments designed to nourish and strengthen your lashes, leaving them looking fuller and healthier. John Aylworth, owner & CEO of FACTORFIVE Skincare explains lash serums provide nutrients and stimulating compounds to the hair follicles along the lash line. These help grow and strengthen the eyelashes.

Serums can be easily applied with precision along the upper lash line or brushed onto the lashes like mascara. While many lash serums claim to promote longer lashes, non-prescription products mainly function as lash conditioners. They help maintain lash health and prevent damage, which can lead to longer lashes over time.

It's worth mentioning these products don’t contain active pharmaceutical ingredients that are scientifically proven to stimulate lash growth. The only lash growth serum that has been clinically proven to be effective is Latisse®, and you’ll need a prescription from your healthcare provider.

How do lash serums work?

Non-prescription eyelash serums work by hydrating and strengthening lashes for a fuller appearance and reduced breakage, which promote longer and fuller lashes. While prescription lash growth serums often include prostaglandins or bimatoprost ophthalmic solution, the key ingredients found in most OTC eyelash serums are:

• Amino acids
• Ceramides
• Hyaluronic acid
• Panthenol
• Peptides
• Biotin

Biotin helps stimulate hair growth, while panthenol, which is made from Vitamin B5, provides essential moisture to keep lash follicles hydrated and healthy.

How long do lash serums take to work?

Most cosmetic lash serums take a minimum of two months of consistent use to show noticeable results. Consistent daily application and following the product’s directions or your healthcare provider’s advice can help you get the results you want.

It's important to note these effects are not permanent. Once you discontinue the serum and the natural growth cycle and anagen phase have been completed, your lashes will return to their original state.

Are lash serums safe to use?

The thinnest skin on your body is on the eyelids. If you have sensitive eyes, you might want to use natural, over-the-counter lash serums made with oil and vitamins instead of stronger prescription serums..

When used as intended, lash serums are generally safe, but there are some things to keep in mind. Like any skincare product, lash serums may contain ingredients that can trigger allergic reactions in some people. The chances of having an allergic reaction depends on the person. Certain peptides, oils, or vitamins could cause redness, itchiness, inflammation, and irritation in and around the eyes. Luckily, there are a range of serums for all kinds of eyes.

Talk with your healthcare provider before experimenting with a lash serum, particularly if you have sensitive skin or eyes, a history of allergies, or light-colored eyes. Bimatoprost can cause a harmless, but sometimes permanent darkening of the iris, which can be more obvious if you have lighter-colored eyes. Conduct a patch test by applying a small amount to an area away from the eyes for a few days. If you experience an allergic reaction, stop using the product immediately and seek guidance from a physician.

What kind of results can I expect to see?

“Visible results typically appear after around two months of consistent use. It's essential to understand that these effects are temporary—once you stop using the serum and the growth cycle ends, your lashes will return to their original state,” says Noordeep Panesar, MD, an internal medical resident who loves to use serums herself.

While both over-the-counter and prescription lash serums can enhance the overall health and aesthetic appeal of your lashes, it’s crucial to maintain realistic expectations. Rapid lash growth or volume is unlikely to be achieved, but consistent use can make your lashes fuller and longer. Best results seem to happen between the two-month and six-month mark, and everyone’s results will vary.

How long should I use a lash serum for?

Using eyelash serums can be quite effective, but it's important to be patient. Typically, it takes two to six months of regular application before you start seeing noticeable results. Consistent and regular application of the serum is essential to achieving the desired effect.

What makes lash serums effective?

Lash serums are designed to improve the health and fullness of lashes through the use of different ingredients that help nourish and encourage the growth of thicker and longer lashes.

Serums are used on the lash line, all along the lashes. Beneficial ingredients can include:

• Argan oil, with linoleic acid that coats, moisturizes, and adds volume to lashes
• Peptides, believed to stimulate hair growth at the follicles
• Keratin, a natural protein that fortifies hair
• Castor oil, which moisturizes the lashes and improves blood circulation at the lash roots to promote growth
• Sodium hyaluronate, serving as a moisture-locking humectant
• Biotin, panthenol, and other vitamins that support hair growth

Bio-engineered ingredients like bimatoprost solution promote lash lengthening but have stronger potential side effects and are only available by prescription.

Prescription lash serums versus over-the-counter options

Prescription-strength Latisse® features the synthetic hormone bimatoprost, which was first prescribed to treat glaucoma. Ophthalmologists, or doctors who diagnose and treat eye conditions, found that bimatoprost unexpectedly caused lash growth. Latisse® is now a bimatoprost solution dedicated to eyelashes.

Bimatoprost requires a prescription from a dermatologist or ophthalmologist, and some users have noted side effects such as irritation, dry eyes, redness, blurry vision, darkened eyelids, and permanent darkening of the iris.

OTC lash growth serums can use a variety of ingredients from organic oils found in plants to scientifically-derived ceramides and hyaluronic acid. This may also include prostaglandin analogs to help stimulate lash growth.

Over-the-counter products are not subject to testing or approval by the Food and Drug Administration (FDA) prior to being marketed. Prescription brands, though, must meet the FDA's rigorous standards for safety, efficacy, and quality before healthcare professionals can prescribe them.

What is prostaglandin?

Prostaglandin analogs, a class of drugs commonly used to treat glaucoma, can have a side effect of lash growth. This has led to the creation of prostaglandin-derived lash serums. Other names for prostaglandin analogs can be isopropyl cloprostenol or isopropyl phenylhydroxypentene dihydroxycyclopentylheptene.

Are there side effects from using prostaglandin-based eyelash serums?

Certain lash enhancers made from prostaglandin could lead to common side effects like discomfort, redness, and irritated eyelids. Less common side effects might involve changes in eye color, a swollen retina, and vision changes.

Can an eyelash serum change your eye color?

Using lash serums originally intended to treat glaucoma, such as prostaglandin-derived ingredients or bimatoprost solution, may lead to darkening of the iris in those with light-colored eyes. As a potential low-risk side effect, be mindful of using these products if you have blue, green, or hazel eyes.

How to get the most out of your lash serum

For best results, most lash serums are applied daily. If you stop using the serum, your lashes will stop growing. For continued results, incorporate the serum into your daily routine.

To ensure a great experience with your lash serum, whether prescription or OTC, make sure the formula is safe for you. Perform a patch test for 24 to 48 hours and check for allergic reactions before using a new lash serum near your eyes.

Frequently asked questions (FAQs)

Can I use lash serums on my brows?

Sometimes. There are a few serums on my list designed for both eyelashes and eyebrows, which are fine to use on both areas of the eye.

Eyebrows are generally fuller and longer than lashes and can handle a more powerful serum. Eyebrow-only serums are usually a thicker fluid to grab onto the less tender area.

Eyelash growth serums are formulated to be a thinner consistency, which enables them to permeate the lash follicles without causing any damage, as they are lighter and less concentrated. This makes them more gentle on the eyes and decreases the risk of irritation.

How to improve eyelashes naturally?

Use oils such as vitamin E, castor, coconut, or almond to maintain the softness and pliability of lashes.

“Castor oil-containing lash serums are thought to work by increasing blood flow to the root of the hair,” explains Dr. Hilal-Campo. “Some lash serums have antibacterial properties and anti-inflammation properties, like castor oil, which has been shown to be an effective treatment for blepharitis, or inflammation of the lash line, which can inhibit the growth of the lashes. Coconut oil also has antibacterial properties, which can help reduce bacteria that can cause inflammation of the lash line and inhibit lash growth.”

Almond oil is also great at boosting luster and nourishment to the lashes. Green tea can also be an effective natural remedy due to its rich epigallocatechin gallate (EGCG) content, a potent antioxidant known to stimulate hair follicle growth.

Additionally, the anti-inflammatory properties of green tea can ease any inflammation and provide a calming effect on the delicate skin surrounding the eyes.

Is lash serum better than castor oil?

The answer depends on your body’s chemistry. You can try single-ingredient formulations like castor oil, coconut oil, or olive oil to lengthen lashes to see if they work for you before trying cosmetic lash serums made of keratin, panthenol, and botanical extracts.

Should you sleep after putting on lash serum?

Make sure to wait for the lash serum to completely dry before going to sleep. Apply a thin layer of serum along the base of your upper lash line using an applicator or a clean eyeliner brush. Don't use too much, because larger amounts of serum can have adverse effects on your eyes.

Don't use serum on any area other than your lash line, as it may lead to unwanted hair growth. Allow the serum to dry for a minute or two before applying any other cosmetics or products to your face. Make sure the lash serum is completely dry before touching or applying anything else to your eyelids.