Tested on animals:Yes
RapidLash is a cosmetic product claiming to grow lashes. Like many companies with their version of lash-growing products, RapidLash seems in to compete with Allergan’s expensive prescription-only version called Latisse, which costs considerably more. Most of these Latisse-wannabes are nothing more than colorless liquid eyeliners with some peptides or plant extracts thrown in even though these have no research showing they can affect hair growth.
The original formula of RapidLash stood apart not only because it costs considerably less than Latisse but it did, at least in theory, work to grow lashes. Sadly, a legal threat from Allergan led to the company changing RapidLash's formula, and the new version no longer contains the potentially effective ingredient found in the original, as we discuss below.
A serious distinction between Latisse and original formula RapidLash is Latisse, as a prescription-only drug, is subject to intense scrutiny, proof of safety and efficacy by the FDA that RapidLash is not. Rocasuba, the company that distributes RapidLash, has done some amount of their own testing, but it pales in comparison to the level of testing Latisse went through to prove what it can and can't do and what risks accompany its benefits.
Claims for RapidLash are carefully worded so they remain strictly cosmetic and not like a drug but here's the difference: the original formula of RapidLash contained an ingredient that quite possibly allows it to work like Lattise. However, as mentioned above, the current formula does NOT contain this ingredient, which is why we no longer recommend RapidLash.
Back to the original RapidLash formula: The active ingredient in Latisse is bimatoprost. Bimatoprost is the active ingredient in the prescription medication Lumigan used to treat glaucoma. Patients with glaucoma who used Lumigan noticed their eyelashes really grew and got darker. Allergan owns Lumigan and so they took advantage of this side effect and obtained FDA approval to sell the active ingredient as a lash growing treatment.
RapidLash's original formula contained an ingredient called isopropyl cloprostenate, which has some distant molecular similarities to bimatoprost. While there is no published research showing isopropyl cloprostenate can grow lashes, its relation to bimatoprost clearly exists.
This association is the likely explanation behind RapidLash original formula's effectiveness. Given the original formula worked similarly to Latisse, it was also possible that the same side effects associated with Latisse could occur when using original formula RapidLash, yet those concerns don't exist for the current formula.
So should you consider trying the latest RapidLash formula for longer lashes and fuller eyebrows? Sadly, no. The Paula's Choice Research Team has used the original formula with much success, though some of us also got a bluish-red discoloration along the lashline. The current formula replaced the isopropyl cloprostenate with a blend of peptides and plant extracts that do not have any substantiated research proving they effect lash growth, volume, or color, and this is the version the majority of online and in-store retailers are selling now.
NOTE: A pricier version of RapidLash is sold as Neulash. These lash-enhancing products are nearly identical and neither is all that effective, so there's no need to spend almost twice as much on Neulash (you may see it on cosmetic counters at Neiman Marcus department stores).