The most effective way to grow longer eyelashes is prescription bimatoprost, marketed in the United States as Latisse. Bimatoprost is FDA-approved for inadequate eyelashes and can increase lash length, thickness and darkness. Results are gradual: clinical studies assess outcomes at 16 weeks, while a 2024 review found limited evidence for many non-prostaglandin lash serums. For a cosmetic change today, use an eyelash curler and mascara. To protect your natural lashes, avoid rubbing, harsh makeup removal and prolonged use of heavy extensions.
The Best Options at a Glance
| Goal | Best option | How quickly it works | Main limitation |
|---|---|---|---|
| Grow natural lashes | Prescription bimatoprost | Noticeable improvement may take about 2 months; studies assess results around 16 weeks | Requires medical guidance and ongoing use |
| Make lashes look longer today | Eyelash curler and lengthening mascara | Immediately | Does not increase lash growth |
| Protect existing lashes | Gentle cleansing and careful makeup use | Over several weeks | Reduces breakage rather than extending the growth cycle |
| Add instant length and volume | False lashes or extensions | Immediately | Adhesives and extensions can irritate the eyes or damage natural lashes |
How Does Bimatoprost Grow Eyelashes?
Bimatoprost is a prostaglandin analog that extends or stimulates the active growth phase of the eyelash follicle. In a randomized clinical trial, 78.1% of people using bimatoprost showed at least a one-grade improvement in overall lash appearance at week 16, compared with 18.4% using the control solution. The treatment also increased lash length, thickness and darkness.
Bimatoprost does not produce permanent growth. After treatment stops, lash growth gradually returns toward its original level. Applying more than directed does not produce extra growth, according to the FDA-approved label.
How to Use Prescription Bimatoprost Safely
Use bimatoprost only as directed by a healthcare professional and the product label:
- Remove makeup and contact lenses.
- Apply one drop to the supplied sterile applicator.
- Brush it along the skin of the upper eyelid margin, at the base of the lashes.
- Use a new applicator for the other eye.
- Blot away excess solution.
- Do not apply it to the lower eyelid or use a homemade brush.
Possible side effects include itching, eye redness, darkening of the eyelid skin and hair growth outside the application area. Bimatoprost can also change iris pigmentation. Increased brown pigmentation of the iris may be permanent. Anyone using glaucoma medication or another product that lowers eye pressure should speak with an eye-care professional before using bimatoprost.
Do Over-the-Counter Lash Serums Work?
Some nonprescription lash serums may condition the lashes or make them look darker and fuller, but their growth claims have less supporting evidence than bimatoprost. The 2024 review cited above found that non-prostaglandin ingredients show potential, but clinical research remains limited. Other prostaglandin ingredients may affect lash growth, but their safety profiles need more study.
Check the ingredient list before applying any serum near the eye. Cosmetics generally do not receive FDA approval before sale, so treat "FDA-approved" claims for cosmetic lash serums with caution.
Can Castor Oil Make Eyelashes Grow?
There is no good evidence that castor oil makes eyelashes grow longer. It may coat the lashes and make them look shinier, but a coating does not change the lash growth cycle. Keep castor oil and other household oils out of the eye because they can cause irritation or blurred vision.
How to Make Lashes Look Longer Immediately
For same-day results:
- Curl clean lashes before applying mascara.
- Choose a lengthening or tubing mascara.
- Apply mascara from the roots toward the tips in a light, even coat.
- Add a second coat while the first is still workable.
- Remove mascara at night without pulling the lashes.
- Replace old or dried mascara instead of adding water or saliva.
The FDA advises following the manufacturer's instructions for discarding mascara, avoiding shared eye cosmetics and stopping use if irritation develops. Manufacturers commonly recommend replacing mascara two to four months after purchase.
How to Protect Natural Lash Length
Lashes can look shorter when they break or shed before their normal growth cycle ends. Reduce avoidable damage by:
- Removing eye makeup without scrubbing.
- Avoiding repeated pulling with eyelash curlers.
- Not picking at mascara or lash glue.
- Keeping makeup tools clean.
- Avoiding eye cosmetics when the eyelids are inflamed or infected.
- Taking breaks from false lashes and extensions if your natural lashes are thinning.
Eyelash extensions can cause allergic blepharitis, irritation, infection and traction alopecia, which is lash loss caused by repeated pulling. The American Academy of Ophthalmology warns that rubbing, tugging or pulling extensions can damage natural lashes and, in some cases, the follicles.
When Short or Thinning Lashes Need Medical Attention
See a dermatologist or ophthalmologist if your lashes suddenly become sparse, fall out in patches or stop growing. Eyelash loss can be linked to alopecia areata, eyelid inflammation, thyroid disorders, skin disease, medication effects or repeated trauma. Treating the underlying cause may allow the lashes to grow back.
Bottom Line
Choose prescription bimatoprost for evidence-backed lash growth, or a curler and mascara for a same-day change. Castor oil and most nonprescription lash serums do not have comparable evidence for making eyelashes grow longer.