Doctors Break Down How Lash Growth Serums Work—And Some Notable Drawbacks

If your goal is to grow thicker and stronger eyelashes with the help of lash serums, doctors tell us that while this is possible, there still are notable and important drawbacks to consider. We checked in with dermatologists and other skincare and hair experts to learn more about how lash serum works, why many enjoy using it and another reason why you might want to reconsider giving it a go if you have more sensitive skin.

Read on for tips, suggestions and insight from Dr. Ekama Carlson, MD, FAAD, FACMS, dermatologist and Mohs surgeon and Dr. Roshan Vara, hair transplant surgeon and co-founder at The Treatment Rooms.

READ MORE: A Dermatologist Tells Us How To Grow Longer Eyelashes

First Off, How Do Lash Serums Work?

The normal life cycle of eyelashes, Carlson explains, has three phases: anagen (growth), catagen (transitional), and telogen (resting). "During the anagen phase, the eyelashes are actively growing and the hair follicle is thick and deeply rooted," she says, adding that this phase "normally lasts for 30-45 days in most people, after which the lash transitions to a resting or telogen phase."

In that one, she continues, the hair follicle "shrivels up over time, and eventually, the eyelash hair falls out, before again transitioning to the growth or anagen phase." If the anagen phase is prolonged with lash serum, she points out, "the result is that each eyelash continues to grow and thicken for a longer period, resulting in longer, thicker lashes."

Lash growth serum, Vara adds, is a product that "helps you to produce more eyelashes, making your eyelashes appear fuller and longer." It does this by helping to hydrate the lashes, as well as stimulating the lash hair follicle which "increases the amount of lashes you will grow." It is specifically made to help your lashes during their growth phase (or anagen phase), he reiterates, to make them "stronger, and plenty." Biotin is an ingredient you will find in most lash serums which is "known to help strengthen hair and keep it healthy," Vara notes.

For some, using a lash serum produces successful results, Carlson says, and there are several reasons why one might want to try it out. "One may try it for sparse eyelashes caused by genetics, a medical illness, or simply if they want longer, fuller eyelashes," she says. Vara adds that a lash serum is "great for those who might not naturally grow many eyelashes."

It can help to make them more voluminous and nourished, he goes on, "giving you long lashes with minimal effort." It is also a "much more affordable option as opposed to lash extensions or lash lifts," and it can provide you with more permanent results. Even still, there are notable drawbacks to using lash serum that Carlson and Vara stress you should be aware of.

Important Lash Serum Drawbacks: Itchiness, Discoloration And More

According to Carlson, the main and most common drawbacks related to lash growth serums "range from mild side effects such as eye irritation, redness, dryness, darkening of the skin around the eye and excessive hair growth outside of the treated areas, to more severe or problematic side effects, such of loss of fat around the eye and thinning of the eyelid skin."

This, she warns, can "result in a hollowing and aging effect, darkening of light eyes over time, and cataracts (clouding of the lenses of the eye) which could cause blurry vision and other eye problems over time." Because of the range of side effects which differ depending on the product used, "one should always consult with a board-certified dermatologist before starting lash growth serums," Carlson emphasizes.

Vara concurs, and says that "unfortunately, lash growth serum isn’t for everyone." A common issue with these products are "allergic reactions which can cause red, itchy eyes, or even hives," he notes. "If you buy a lower-quality product, you could also experience some side effects and it could cause a burning or irritating sensation," he adds. Vara also points out that it can be "very uncomfortable" if you get this product in your eyes.

"In some cases, lash serum can cause skin discoloration which may not be reversible," Vara says. "It’s important to always use caution when using a product so close to your eyes and always do a skin patch test somewhere else on your body before applying directly to your eyelids."

What Is The Best Type Of Lash Serum?

Overall, Carlson concludes that the most "effective and best-studied lash growth serums contain prostaglandins (PG) or similar compounds called prostaglandin analogs (PGA) as their active ingredient." Both PG and PGAs are drugs that are "primarily used to treat an eye disease called glaucoma."

A welcome side effect during use of these drugs in initial studies was "dramatic growth of longer, darker, and thicker eyelashes," she says, which is how lash serums came to exist."Lash serums containing PG are available only by prescription by a doctor, and can be obtained by visiting a dermatologist or plastic surgeon’s office," she advises, adding that "over-the-counter lash growth products are also available and may contain PGAs."