What Is Isopropyl Cloprostenate?
Part of Series on Lash Serum Safety
Isopropyl cloprostenate (ICP) is a synthetic prostaglandin F2-alpha analog used in some over-the-counter cosmetic eyelash serums. It binds to the same FP prostaglandin receptors as prescription prostaglandin drugs like bimatoprost (the active in Latisse), which classifies it pharmacologically as a drug ingredient. Health Canada banned ICP from Canadian cosmetics in 2019, though it remains in some US over-the-counter products. If you're searching for a prostaglandin-free lash serum, look for formulas that omit ICP and related compounds entirely.
How ICP works
Prostaglandin F2-alpha analogs activate FP receptors on the dermal papilla — the cluster of cells at the base of each hair follicle that controls the growth cycle. Activation extends the anagen phase of the follicle, which is why prostaglandins were originally developed for treating glaucoma and were later observed to lengthen eyelashes as a side effect. Bimatoprost was eventually FDA-approved as the prescription drug Latisse for hypotrichosis (inadequate eyelashes), with physician supervision.
Where ICP appears
ICP is the active ingredient in GrandeLASH-MD, and it appears in several other over-the-counter lash serums sold in the US. Because ICP is sometimes labeled under chemical synonyms, the same compound may also be listed as cloprostenol isopropyl ester, or with prostaglandin-suffix variants ending in -prostenol, -prostal, or -prostenolamide.
Documented side effects
ICP shares the side-effect profile of other prostaglandin analogs. Ophthalmologists describe these collectively as prostaglandin-associated periorbitopathy (PAP):
- Iris pigmentation: permanent darkening of the iris, most noticeable in mixed-color (hazel, green-brown) eyes. Documented in the FDA prescribing information for bimatoprost.
- Orbital fat atrophy: loss of fat around the eye, producing a sunken or hollowed appearance.
- Eyelid hyperpigmentation: skin darkening around the eyelid margin.
- Deepening of the upper eyelid sulcus: change in the upper eyelid contour.
- Dry eye, redness, and chronic irritation.
Recovery after discontinuation is variable and not guaranteed. Some changes — particularly iris pigmentation — are considered permanent.
The 2019 Canadian ban
In 2019, Health Canada formally classified ICP as a drug ingredient and prohibited its inclusion in cosmetic products. The decision reflected ICP's pharmacological similarity to prescription prostaglandin drugs and the absence of physician oversight in over-the-counter cosmetic use. The compound remains permitted in US OTC cosmetics, with no equivalent federal action.
Cosmetic class action context
In 2018, Grande Cosmetics settled Lopez v. Grande Cosmetics for $6.25 million over claims that GrandeLASH-MD's marketing did not adequately disclose ICP's drug-like effects.
Avoiding ICP and other prostaglandin analogs
To avoid ICP, check the ingredient list for the names above and the prostaglandin-suffix patterns. Peptide-based and plant-based serums offer a different mechanism — both categories qualify as hormone-free lash serums. For a competitive breakdown of named brands, see the prostaglandin-free lash serum comparison.
Plume Elite uses a 5-peptide clinical complex paired with a patented forskolin and ricinoleic acid blend to support the look of visibly fuller-looking lashes and brows. The formula is prostaglandin-free, hormone-free, and ophthalmologist-endorsed.
Looking for the hormone-disruption angle specifically? See what makes a lash serum genuinely hormone-free.