Ingredient review
Cyclopropylbimatoprost
INCI: Cyclopropylbimatoprost
A potent eyelash growth ingredient that works but can cause irritation and darkening of the eyelid skin or iris.
In plain English
Cyclopropylbimatoprost is a lab-made ingredient similar to a natural substance called prostaglandin. When applied to the lash line, it encourages eyelashes to grow longer, thicker, and darker. However, it can also cause side effects like redness, itching, and darkening of the skin where applied, and in rare cases, it may permanently darken the iris (the colored part of the eye). It is not a moisturizer or conditioner—it actively changes hair growth cycles.
Review score
Safety, usefulness, and evidence
Potentially useful with some tradeoffs
The evidence base is useful, but some claims depend heavily on the formula.
Main practical flags: irritation is moderate; clogging risk is low.
- Source
- synthetic
- Evidence
- moderate
- Irritation
- moderate
- Clogging risk
- low
Quick decision guide
Useful, but context matters
Cyclopropylbimatoprost can be useful, but watch for some irritation potential.
Plain-English read
Treat this as a practical screening step before you compare products that contain this ingredient.
- Step 1Start with the score, then check the irritation and clogging risk before judging Cyclopropylbimatoprost.
- Step 2Use the "Best for" and "Use caution if" sections to match the ingredient to your skin, not just to a marketing claim.
- Step 3If a product stings, breaks you out, or worsens irritation, judge the finished formula and stop using it even if the ingredient scores well.
Score terms in plain English
Irritation risk
moderateCan bother some users, especially with frequent use, damaged skin, or strong companion ingredients.
Clogging risk
lowLess likely to feel heavy or contribute to clogged pores for most skin types.
Evidence level
moderateThere is useful support, but formula details and claim strength still matter.
What it is
A synthetic analog of bimatoprost, which is a prostaglandin analog originally developed for glaucoma treatment. It is used in cosmetic eyelash serums to enhance lash growth.
How it works
It binds to prostaglandin receptors in the hair follicle, prolonging the anagen (growth) phase of the eyelash hair cycle and increasing the number of hairs that are actively growing. This results in longer, thicker, and darker lashes over several weeks of consistent use.
Pros
Effective lash growth
Clinical studies show it significantly increases lash length and thickness within weeks.
Long-lasting results
With continued use, lashes stay longer and fuller, and results can be maintained with regular application.
Cons and cautions
Eye irritation risk
Common side effects include redness, itching, and a burning sensation around the eyes.
Permanent pigment changes
It can darken the eyelid skin and, rarely, the iris, which may be irreversible.
Best for
- People seeking visibly longer and fuller eyelashes
- Those who have tried gentler lash serums without results
Use caution if
- People with glaucoma or other eye conditions
- Those with sensitive eyes or a history of eye irritation
Usage tips
Safety summary
Cyclopropylbimatoprost is effective for eyelash growth but carries moderate risks of eye irritation and pigment changes. It should be used with caution, especially by those with sensitive eyes or eye conditions.
Research notes
Studies show it reliably increases lash length and thickness, but most evidence comes from its parent compound bimatoprost. Long-term safety data for cosmetic use is limited.
Common label clues
- Typical concentration
- Typically 0.01% to 0.03%
- Regulatory status
- Approved as a prescription drug for glaucoma; used in cosmetics at lower concentrations, but not FDA-approved for cosmetic use.
- Common uses
- Eyelash serums
- Environmental note
- Synthetically produced, so no direct environmental impact from harvesting, but disposal of unused product should follow local guidelines.
Good to know
- This ingredient is often found in prescription-strength lash serums; over-the-counter versions may contain lower concentrations.
- If you wear contact lenses, remove them before application and wait 15 minutes before reinserting.
Common questions
What is Cyclopropylbimatoprost in beauty products?
Cyclopropylbimatoprost is a lab-made ingredient similar to a natural substance called prostaglandin. When applied to the lash line, it encourages eyelashes to grow longer, thicker, and darker. However, it can also cause side effects like redness, itching, and darkening of the skin where applied, and in rare cases, it may permanently darken the iris (the colored part of the eye). It is not a moisturizer or conditioner—it actively changes hair growth cycles.
What does Cyclopropylbimatoprost do in a beauty product?
It binds to prostaglandin receptors in the hair follicle, prolonging the anagen (growth) phase of the eyelash hair cycle and increasing the number of hairs that are actively growing. This results in longer, thicker, and darker lashes over several weeks of consistent use.
Is Cyclopropylbimatoprost safe for most people?
Cyclopropylbimatoprost is effective for eyelash growth but carries moderate risks of eye irritation and pigment changes. It should be used with caution, especially by those with sensitive eyes or eye conditions.
Who should be careful with Cyclopropylbimatoprost?
People with glaucoma or other eye conditions Those with sensitive eyes or a history of eye irritation
Research sources
Ingredient reviews are educational and are not medical advice. Patch test new products and ask a licensed clinician about persistent irritation, allergies, pregnancy-specific questions, or diagnosed skin conditions.