Who doesn't want long, luscious eyelashes? For years all we could do was paint them and stick on falsies, then Latisse landed on the market, promising to make your natural lashes gorgeous and doe-y. But how does it work?
Lashes, like all hair, grows in a cycle, which involves 3 phases and takes 5-12 months.
Anagen - This is when the hair is growing and getting longer. This lasts 1-2 months, and the lash grows around 0.15 mm a day. In total, this means lashes will grow to about 9 mm long, with 2 mm staying under the skin.
Catagen - Once the hair has finished growing, the growing base dies and form a club under the skin. Catagen lasts about 15 days.
Telogen - This is when the lash just sits in the skin. Once anagen starts, the new hair pushes the old hair out of the follicle (exogen). Telogen lasts 4-9 months.
In humans, individual hairs are in different stages of the cycle, so we don't have a shedding period (like in dogs) where we lose lots of hair at once. About 41% of eyelashes are in the anagen phase at any time.
What is Latisse?
Latisse is a solution containing 0.03% bimatoprost, a synthetic prostamide. It was originally used as a treatment for ocular hypertension, when there's too much fluid in the eyeball. Patients reported unusual eyelash growth, and so, a new drug was born! (This happens quite a lot - scientific discoveries are usually thanks to sheer luck!)
How does bimatoprost work?
A lot of the exact mechanism of how bimatoprost works is currently unknown. What we do know:
Bimatoprost doesn't increase the number of lashes that can grow - at the moment, there's no proven way of changing the number of hair follicles.
Studies in mice suggest that it works by making lashes stay in the anagen (growing) phase for longer, which increases the lash growing time, and means longer lashes. Scalp hair grows for 6-8 years, which is why it's so much longer! This also means new lashes form quicker, and old lashes fall out slower, so there are more visible lashes coming out at any time, which gives you denser lashes.
Bimatoprost also increases the width of the bulb (the fat bit at the bottom), which makes the lash grow thicker. This effect is more noticeable with shorter hairs in the early stages of growth than longer lashes.
The darkening of lashes treated with bimatoprost comes from stimulating the production of melanin, a chemical pigment that gives skin, hair and eyes their colour.
The most common side effect is eye redness, which will happen if you put things near your eyes!
Additionally, lashes aren't the only things that have melanin - as well as making your lashes darker, bimatoprost can also make your skin and eyes darker.
Skin darkening can be noticeable after a few months of use, and usually goes away after you stop using bimatoprost.
Darkening of the irises - the coloured bit of the eye - was reported by 1.5% of people in a clinical trial when bimatoprost eyedrops are used, but when it was just used to paint the lashline, there were no reports of it happening. There's obviously less contact with the eye when using bimatoprost only on the lashline, and a lot less is used than in an eyedrop (approximately one-twentieth of the amount). However, it's a potentially permanent side effect, so light-eyed girls be careful!
Have you used Latisse? Did it work for you?
J L Cohen. Enhancing the growth of natural eyelashes: the mechanism of bimatoprost-induced eyelash growth. Dermatol Surg 2010, 36, 1361.