If you have a lash serum on your vanity and brows that look sparser than they used to, it is tempting to brush a little serum through them too. Brows and lashes are both short facial hairs, so it seems logical. But brow hair behaves differently, and what is in your serum matters a lot.
This guide explains how brow hair differs from lashes, what the research says about prescription bimatoprost on eyebrows, and how to use a cosmetic serum on brows safely if you want to try it. If you have not chosen a serum yet, start with our guide to lash serum types and ingredients and our explainer on prostaglandin-free lash serum.
Key takeaways
- Eyebrow hairs cycle more slowly than eyelashes, with a growth phase of about 4 to 7 months [1].
- Prescription bimatoprost (Latisse) is FDA-approved only for eyelashes. Using it on brows is off-label and belongs with a doctor [2][3].
- A prostaglandin-free cosmetic serum can condition brow hairs so brows look fuller and more groomed. It does not grow hair.
- Sudden or patchy brow loss can signal a medical issue and is worth a visit to a doctor or dermatologist.
How eyebrow hair differs from eyelashes
Like lashes, brow hairs cycle through growing (anagen), transition (catagen) and resting (telogen) phases. The timing is quite different, though. According to an NIH StatPearls anatomy reference, eyelashes grow for about 4 to 10 weeks and rest for about 4 to 9 months, while eyebrows grow for about 4 to 7 months, transition for about 3 to 4 weeks, and rest for about 9 months [1].
| Phase | Eyelashes | Eyebrows |
|---|---|---|
| Anagen (growing) | About 4 to 10 weeks [1] | About 4 to 7 months [1] |
| Catagen (transition) | About 15 days [1] | About 3 to 4 weeks [1] |
| Telogen (resting) | About 4 to 9 months [1] | About 9 months [1] |
In practice, that means brow changes of any kind tend to show up slowly. It also means patience matters even more on brows than on lashes. For the lash side of the story, see How Long Does Lash Serum Take?
What the research says about bimatoprost on brows
Bimatoprost 0.03% is sold as Latisse, a prescription drug the FDA approved to treat hypotrichosis of the eyelashes [2]. Its approval covers eyelashes only. Because it clearly affects lash growth, researchers and dermatologists have looked at whether it might help eyebrows too.
A 2018 case report and literature review in Cureus described a woman with eyebrow hypotrichosis who applied bimatoprost to her brows daily for eight months, and reviewed earlier eyebrow studies [3]. A 2017 review in Expert Opinion on Investigational Drugs discussed bimatoprost for eyelash, eyebrow and scalp hair loss and suggested brows might also benefit, while noting the FDA approval is for eyelashes [4].
By the numbers
- In a review of bimatoprost for eyebrow hypotrichosis (Riahi and Cohen, Cureus, 2018), studies covered 421 patients in total, with improvement first seen around 8 weeks and the most change at about 6 to 8 months [3].
- In the NIH StatPearls reference Anatomy, Head and Neck: Eyelash (Patel et al., updated 2023), the eyebrow resting phase lasts about 9 months [1].
Why this is a doctor conversation
Using a prescription drug on your brows is off-label, and it carries the drug’s side effects. The Latisse label warns about darkening of the skin around the eyes, possible permanent darkening of the iris, and hair growth where the solution repeatedly touches the skin [2]. The same Cureus review noted skin irritation and itching in some brow study participants [3]. If you are interested in this route, talk to a dermatologist or eye doctor. Our article on prostaglandin lash serum side effects explains these risks.
Some over-the-counter lash serums contain prostaglandin analogs too. If you want to avoid that ingredient type on your face, our guide to spotting prostaglandin analogs on a label shows what to look for.
Using a prostaglandin-free cosmetic serum on brows
A prostaglandin-free cosmetic serum is a different kind of product. It is not a drug and does not grow hair. What it can do is condition brow hairs, much as it conditions lashes, so brows can look fuller, softer and more groomed. Many people simply use the same serum on both.
XXtraLash, for example, is made for the lash line and uses conditioning peptides, bioengineered sh-polypeptides and soothing botanicals like aloe and sage. Learn more in peptides in lash serums explained.
How to apply serum to your brows
- Start clean. Wash and dry your brows, and remove brow makeup first.
- Patch test. Try a small amount on one area of skin and wait a day or two before using it all over.
- Use a thin layer. Brush a light coat through the brow hairs and onto the skin beneath, following the direction of growth.
- Keep it away from your eyes. Do not let product drip toward the eye, and use less near the inner corners.
- Let it dry before applying brow gel, pencil or powder.
- Be consistent and patient. Because brows cycle slowly, give a cosmetic routine a fair trial over several months before judging how your brows look, and take photos to compare.
Our lash serum application guide covers the lash technique if you plan to use one bottle for both.
Brow habits that matter more than any product
- Go easy on plucking and waxing. Repeated pulling can damage follicles over time.
- Avoid rubbing your brows hard when cleansing or removing makeup.
- Be cautious with brow tints. The FDA warns that permanent eyelash and eyebrow tints and dyes have been known to cause serious eye injuries [5].
- Never share brow or eye products, and stop any product that causes irritation [5].
Brow serum, lash serum: is there a difference?
Products sold as brow serums and lash serums are often very similar. Both are usually light, leave-on liquids designed to condition short facial hairs. The main practical differences are the applicator and how close to the eye the product is meant to go. A lash serum uses a fine brush for the lash line, while brow products often have a wider brush or spoolie.
What matters most is the ingredient list, not the label on the front. If a product contains a prostaglandin analog, it carries the same kinds of risks whether it is called a lash serum or a brow serum [2]. If it is prostaglandin-free, it is working as a conditioning cosmetic. Our guide on how to choose the best prostaglandin-free lash serum walks through what to check.
Can one bottle do both?
Many people use a single lash serum for lashes and brows. If you do, apply to your lashes first with a clean brush, then to your brows, so you are not carrying brow makeup or skin oils toward your eyes. Keep the cap closed tightly between uses and never share the bottle [5].
Why brows thin in the first place
Eyebrows often thin gradually with age, and years of over-plucking can leave some areas sparse. But brow loss can also be linked to thyroid problems, alopecia areata, eczema or psoriasis, nutritional issues, and some medications. Brows and lashes thinning at the same time is worth mentioning to a doctor. Our articles on thinning eyelashes after 40 and thin or falling eyelashes discuss related causes.
Setting realistic expectations
A cosmetic serum works on the brow hairs you already have. It can make them look softer, glossier and better groomed, which often makes brows look fuller overall. It will not fill in a bare patch where follicles are no longer producing hair. If you are hoping to restore real brow growth, that is a medical question, and a dermatologist can explain options and whether a prescription approach makes sense for you [4].
When to see a doctor
Please see a doctor or dermatologist if you notice:
- Sudden, patchy, or rapid loss of brow hair or lashes.
- Red, scaly, itchy or painful skin on or around your brows.
- Hair loss together with tiredness, weight change, feeling cold, or other new symptoms.
- Irritation from any product that does not settle after you stop using it.
These can have treatable causes, and a professional can help. Our lash resources page explains how to find a dermatologist or eye doctor.
One prostaglandin-free serum for your lash line
XXtraLash is a prostaglandin-free eyelash serum that conditions lashes for a longer-looking, fuller-looking lash line. Each 3 mL bottle comes with a precision brush for applying right along the lash line.
Frequently asked questions
Can I put lash serum on my eyebrows?
Many people apply a cosmetic lash serum to their brows. A prostaglandin-free conditioning serum can help brow hairs look fuller and more groomed, the same way it conditions lashes. Patch test first, keep it away from your eyes, and stop if your skin gets irritated.
Is Latisse approved for eyebrows?
No. Latisse (bimatoprost 0.03%) is FDA-approved only for hypotrichosis of the eyelashes. Some doctors have studied or used it on eyebrows, but that is outside its approved use and should only happen under a doctor’s guidance.
How long does it take to see a difference on brows?
Brow hairs cycle more slowly than lashes. One anatomy reference puts the eyebrow growth phase at about 4 to 7 months and the resting phase at about 9 months. In studies of prescription bimatoprost on brows, improvement was first seen around 8 weeks, with the most change at about 6 to 8 months. Expect any cosmetic change to look gradual too.
Will lash serum fill in over-plucked brows?
A cosmetic serum does not regrow hair. If brows have been over-plucked for years, some follicles may not recover. A dermatologist can explain your options.
Can I use lash serum on my brows while pregnant?
Check with your doctor before using any lash or brow serum during pregnancy or breastfeeding, and avoid prescription prostaglandin products unless your doctor approves.
Why are my eyebrows thinning?
Brow thinning has many possible causes, including over-plucking, aging, thyroid problems, alopecia areata, skin conditions and some medications. If thinning is sudden, patchy, or comes with other symptoms, see a doctor or dermatologist.
Related reading
- How to Apply Lash Serum the Right Way
- Peptides in Lash Serums: Myristoyl Pentapeptide-17 Explained
- Latisse vs. Over-the-Counter Lash Serums: What’s the Difference?
- Prostaglandin Lash Serum Side Effects: Darkened Lids, Eye Color and Fat Loss
- Thinning Eyelashes After 40: What Changes and What Helps
- How Long Does Lash Serum Take? The Lash Cycle Explained
Sources
- Patel BC, Lopez MJ, Joos ZP. Anatomy, Head and Neck: Eyelash. StatPearls, NCBI Bookshelf, updated 2023.
- U.S. FDA. LATISSE (bimatoprost ophthalmic solution) 0.03% prescribing information (FDA Label database).
- Riahi RR, Cohen PR. Topical Treatment of Eyebrow Hypotrichosis with Bimatoprost 0.03% Solution: Case Report and Literature Review. Cureus, 2018.
- Barron-Hernandez YL, Tosti A. Bimatoprost for the treatment of eyelash, eyebrow and scalp alopecia. Expert Opinion on Investigational Drugs, 2017.
- U.S. FDA. Eye Cosmetic Safety.
