Does bimatoprost make eyebrows grow? The science, off-label use, and potential side effects

October 7, 2025 •

5 min read

Originally approved by the FDA in 2008 for treating hypotrichosis of the eyelashes, the active ingredient bimatoprost was later studied for other areas, including eyebrows. So, does bimatoprost make eyebrows grow? While used off-label for this purpose, studies and clinical reports suggest it can increase eyebrow hair density and length.

Quick Summary

Bimatoprost, the active ingredient in Latisse, is used off-label to enhance eyebrow growth by extending the hair cycle. Studies indicate it can increase density and length, though results vary, require continuous use, and come with potential side effects.

Key Points

Extends the hair growth cycle: Bimatoprost works by prolonging the anagen (growth) phase of hair follicles, leading to longer and thicker hairs.
Effective for off-label use: Although FDA-approved only for eyelash growth, clinical studies and doctor-prescribed off-label use confirm bimatoprost's effectiveness for improving eyebrow density and length.
Requires continuous application: The hair-growing effects are temporary and will reverse if the medication is discontinued, requiring consistent, long-term use to maintain results.
Comes with potential side effects: Possible side effects include eyelid skin darkening, irritation, redness, and in rare cases, a permanent change in iris color.
Mandates a prescription: Bimatoprost (under brands like Latisse) is a prescription-only medication, and its use should be supervised by a healthcare provider.
Results vary by individual: The timeline and extent of improvement differ for each person, with noticeable changes often appearing between two and eight months.
Proper technique is essential: Applying the solution carefully and blotting excess is necessary to target the eyebrows and avoid unwanted hair growth elsewhere.

Understanding Bimatoprost and Hair Growth

Bimatoprost is a synthetic prostaglandin analog, a class of fatty acids with hormone-like effects in the body. It was first developed and approved to treat glaucoma and ocular hypertension by lowering pressure inside the eye. A serendipitous discovery revealed that patients using the eye drops experienced longer, thicker, and darker eyelashes. This led to the development of Latisse, an ophthalmic solution containing 0.03% bimatoprost, specifically for the treatment of eyelash hypotrichosis (inadequate lashes).

The mechanism behind hair stimulation

Bimatoprost’s ability to promote hair growth is rooted in its influence on the hair growth cycle. The hair cycle has three main phases: anagen (growth), catagen (transition), and telogen (resting). Bimatoprost is believed to extend the anagen phase, keeping hair follicles in a state of active growth for a longer period. This prolonged growth phase results in longer and thicker hairs. Furthermore, the medication can stimulate melanogenesis, the process that produces pigment, which can lead to darker hair color.

For eyebrows, this mechanism works similarly. By prolonging the anagen phase of eyebrow hair follicles, bimatoprost can help enhance the fullness and length of the brows. It can also make fine or vellus hairs more noticeable by darkening them.

Clinical Evidence for Eyebrow Growth

While the FDA has not approved bimatoprost for eyebrow growth, medical professionals often prescribe it “off-label” for this purpose based on clinical judgment and supporting studies. Several studies have investigated its effectiveness:

2016 Study (Carruthers et al.): A randomized, double-masked trial involved 357 participants with eyebrow hypotrichosis. Patients using 0.03% bimatoprost, once or twice daily, showed significantly greater improvement in eyebrow fullness and darkness compared to those using a placebo. Over 7 months, 77.1% (once-daily) and 83.9% (twice-daily) of bimatoprost users achieved at least a one-grade increase on the Global Eyebrow Assessment scale, versus 43.0% for the vehicle-only group.
2019 Study (Suchonwanit et al.): A smaller split-face study on 30 patients showed that both 0.01% and 0.03% bimatoprost significantly improved eyebrow density and diameter after 16 weeks. The 0.03% concentration was numerically, though not statistically, more effective.
2024 Study (Załęcki et al.): A prospective study compared a bimatoprost cosmetic preparation to sweet almond oil. Participants reported significantly greater improvement in eyebrow density and elongation with bimatoprost over 5 weeks. It’s worth noting that participants' perceived satisfaction was much higher with bimatoprost.

The Realities of Using Bimatoprost

How to apply bimatoprost for eyebrows

Proper application is crucial to maximize results and minimize side effects. The general steps are based on the FDA-approved method for eyelash application, adapted for eyebrows.

Cleanse: Start with a clean, makeup-free face, especially around the eyebrow area.
Prepare: Place one drop of the bimatoprost solution onto a new, sterile applicator. Never reuse an applicator to prevent contamination.
Apply: Carefully trace the applicator along the length of the brow, ensuring even coverage. Use a fresh applicator for the other brow.
Blot: Gently blot any excess solution that may have strayed beyond the brow line with a tissue to prevent unwanted hair growth in other areas.
Frequency: For optimal results, apply once daily, typically in the evening.

What to expect and timeline

Results are not immediate and require patience and consistency. While some notice improvements within a month or two, maximum results typically take between two and four months of continuous daily application. Because eyebrow hair has a longer growth cycle than eyelashes, it may take slightly longer to see a significant difference. It is important to understand that the effects are temporary. If you stop using bimatoprost, your eyebrows will gradually return to their original appearance over several weeks or months.

Potential side effects

While generally well-tolerated, bimatoprost can cause side effects, which may include:

Eyelid skin darkening: This is a common side effect and is usually reversible upon discontinuation of treatment.
Itching or irritation: Mild irritation or itchy eyes are common but often resolve on their own.
Conjunctival hyperemia: Redness of the eyes is another potential side effect.
Hair growth in unintended areas: Accidental application or runoff can cause hair growth on other parts of the face. Proper application and blotting are essential.
Permanent iris color change: In rare cases, bimatoprost can cause the colored part of the eye (iris) to turn brown, which is permanent. This is more commonly associated with long-term use for glaucoma and is less of a risk with topical application to the brows, but users should be aware.

Bimatoprost vs. Other Eyebrow Treatments


Feature	Bimatoprost (Latisse)	Eyebrow Makeup	Microblading / Permanent Makeup
Mechanism	Extends the hair growth cycle, leading to thicker, longer, and darker hair.	Adds temporary color and shape to create the illusion of fullness.	Involves tattooing pigment into the skin to create semi-permanent hair-like strokes.
Effectiveness	Clinically proven to increase hair density and length for those with sparse brows, especially with consistent use.	Instant but temporary effect. Only covers the skin and existing hairs.	Provides a longer-lasting, defined shape but is not real hair. Fades over time.
Longevity	Requires daily, continuous use. Effects reverse if use is stopped.	Lasts until washed off. Reapplication is needed daily.	Lasts 1-3 years before touch-ups are needed.
Cost	Can be expensive and is usually not covered by insurance. Cost varies.	Varies widely from affordable pencils to high-end products.	High upfront cost (hundreds to over a thousand dollars) but is a long-term solution.
Side Effects	Potential for eyelid darkening, itching, and rare permanent iris color change.	Typically minimal, but some individuals may have skin sensitivity to certain ingredients.	Risks include infection, allergic reaction, scarring, and dissatisfaction with the result.
Convenience	Daily application at night is required. Requires a prescription.	Quick and easy to apply and remove daily. No prescription needed.	Requires an initial multi-hour appointment and follow-up touch-ups.

Conclusion

Does bimatoprost make eyebrows grow? The answer, supported by clinical studies and dermatological practice, is yes, it can be an effective treatment for eyebrow hypotrichosis, or sparse brows. By extending the hair's natural growth cycle, it helps produce longer and thicker hairs. However, it is essential to remember that its use for eyebrows is off-label and requires a prescription and the supervision of a healthcare professional. Before starting treatment, individuals should be fully informed of the potential side effects, including temporary skin darkening and the very rare possibility of permanent iris color change. As the effects are not permanent, consistent and long-term application is necessary to maintain results. For those seeking fuller brows, a thorough consultation with a doctor can help determine if bimatoprost is the right choice, weighing the benefits against the potential risks.

Learn more about hair growth and its complexities at the National Cancer Institute's drug dictionary.

Frequently Asked Questions

No, bimatoprost (the active ingredient in Latisse) is not FDA-approved specifically for eyebrow growth. Its use for this purpose is considered "off-label" but is supported by several clinical studies and prescribed by dermatologists.

Noticeable improvements may be seen within two to three months of consistent daily use, but full results can take up to seven or eight months due to the eyebrow's longer hair growth cycle compared to eyelashes.

The hair-growing effects of bimatoprost are temporary. If you stop using the medication, your eyebrows will gradually return to their original appearance and density over several weeks or months.

Common side effects include temporary darkening of the eyelid skin, itchy eyes, eye irritation, and redness. These usually resolve when treatment is stopped.

A permanent change in iris color to brown is a rare side effect, most often associated with long-term glaucoma treatment where the eye drop is applied directly into the eye. While the risk is lower with topical eyebrow application, it is still a potential risk that users should be aware of.

Apply a single drop to a clean, sterile applicator and carefully trace it along the eyebrow line once daily, preferably in the evening. Be sure to use a fresh applicator for each eyebrow and blot any excess solution with a tissue to prevent unwanted hair growth.

If you wear soft contact lenses, you should remove them before applying bimatoprost to your eyebrows and wait at least 15 minutes before reinserting them.