Along with the eyelashes, eyelash extension adhesives are one of the most important supplies that are needed by professional lash technicians or beauty salons. Synthetic lashes need to be attached effectively with a quality adhesive to give you great results.
What are eyelash extension glues? What are they made of? Are they harmful to your eyes or lashes?
As an eyelash technician myself, I often find myself educating my clients about lash glue.
In this article, I wanted to share the complete ins and outs of lash adhesives whether you’re getting a new set or doing one for your first client. We’ll simplify everything you need to know so that you can make a well-informed decision about the best adhesive for you or your client.
Let’s dive in!
Understanding The Basics: What Are Eyelash Extension Adhesives
Eyelash extension adhesives are used to bond extensions onto your natural eyelashes.
The application process is fairly straightforward. Lash techs dip the bottom of the lash extension fiber, about two millimeters or three into the lash adhesive before fixing it atop the natural lashes.
If you’re thinking why not use any type of adhesive, the truth is that the wrong adhesive can not only lead to lash loss but serious allergies or even eye damage. That’s why it’s critical lash treatments are conducted by licensed professionals only.
Choosing the right lash glue plays a huge role in the quality of the service you will receive and the retention of your lash extensions.
Eyelash Extension Glue Ingredients
|Adhesive ingredient||80-95% of cyanoacrylate (eg. ethyl, methyl, butyl, ethoxyethyl, or octyl cyanoacrylate)|
|Thickening agent||5-10% of PMMA or acrylic resin|
|Coloring agent||E.g. Carbon black, anthraquinone color|
|Stabilizing agent||E.g. Hydroquinone or hydroxyanisole|
|Other compounds||E.g. latex to add flexibility|
Many other ingredients may be potentially added, and thus it is important to pay attention to what is included in the formula.
Here is an example of a typical eyelash extension adhesive.
Eyelash extension adhesives are made of adhesive ingredients, thickening agents, stabilizing agents, coloring agents, and may contain other compounds for various purposes.
The main binding ingredient of lash adhesives is ‘cyanoacrylates’ that can bind quickly and properly with the human skin, hair, and other organic tissues as well as natural fibers, wool, leather, and fiber too.
No matter where you’re getting your new eyelashes or got it, cyanoacrylate or a form of it will always be present in every type of adhesive for extensions. Popularly called ‘CA’ in the industrial world, this instant lash extension adhesive is also found in Super Glue® or Krazy Glue.
If you get down to basics, cyanide and acrylate come together to form cyanoacrylate. Cyanide thickens the adhesive while acrylate is derived from acrylic acrid that helps to harden the glue when laid in the open air.
The Royal Science of Chemistry says that cyanoacrylate is a plastic or acrylic resin that appears as a liquid but when in contact with moisture, it reacts to create polymer chains that solidify fast. Used in medical to industrial, household and now, cosmetic uses, you might’ve come into contact with cyanoacrylates while using acrylic nails.
Fun Fact: During the Vietnam War, a type of cyanoacrylate glue spray was used to cover up wounded soldiers quickly and ended up preventing many cases of fatal blood losses at the time.
You must understand that the same type of cyanoacrylate that’s used in Super Glue isn’t the same one used to bond eyelash extensions. In fact, cyanoacrylate has many derivatives from ethyl, methyl, butyl, octyl, methoxy, alkoxy, and more for binding different things to different surfaces.
Let’s zoom into the main three cyanoacrylates used for topical applications in the cosmetic industry.
- Ethyl Cyanoacrylate: This is the most common type of cyanoacrylate used in lash adhesives today. The ethyl variety of cyanoacrylate is often thicker than other lash adhesives. It is associated with a fast drying time and many manufacturers making ethyl cyanoacrylate-based adhesives claim that the retention is up to 6 weeks.
- Butyl Cyanoacrylate: Another cyanoacrylate ester used in medical applications, butyl cyanoacrylate features a slower drying time than ethyl cyanoacrylate but produces less formaldehyde during the curing process. Butyl cyanoacrylate adhesives are commonly used in the medical field.
- Ethoxyethyl cyanoacrylate: This variety of cyanoacrylate guarantees smoothness and flexibility of lash extensions atop natural lashes when affixed. It provides a soft feel. Out of the three, Ethoxyethyl cyanoacrylate glues will have the weakest bond and will take the longest to dry. However, they are also the most gentle glues and are recommended for sensitive clients.
Poly Methyl Methacrylate
The primary ingredient that makes the extension fiber stay fixed to your natural lashes owes it to PMMA or Poly Methyl Methacrylate. It’s an acrylic glass that shows mild stickiness.
The rule of thumb is if an adhesive contains higher PMMA, the longer the hold. PMMA is so strong that it’s used for bone remodeling too.
Another common element of an eyelash adhesive is hydroquinone or ‘the lash antioxidant’. Most importantly, it prevents the lash adhesive from drying out quickly. The bonus of hydroquinone is that it remains in its liquid form but instantly solidifies when it comes into contact with air.
Do you know where the rich dark color of the black lash extension comes from? It comes from carbon Black.
Carbon black is nothing but burned hydrocarbons or soot often used in a range of cosmetic products like eyeliners, mascaras, eye shadow, eyebrow pencils, and so on.
Using a black-colored adhesive will make your lash extensions look more natural when compared to a transparent adhesive.
However, transparent lash glues still have a role to play since some clients might experience sensitivities to the carbon black ingredient used in most lash adhesives.
What Is Formaldehyde And Is It Dangerous?
One of the most controversial keywords in the eyelash extension industry is ‘formaldehyde’. Let’s clear the air about it with some hard-cold facts before we go any further into lash adhesives.
Formaldehyde is a colorless chemical that’s industrially and otherwise found in the body as well. Our bodily enzymes break it into acids and gases. It’s also present in 0.03 parts per million in the air inside and outside our houses too according to the American Cancer Society.
If you’ve done hair smoothening, straightening, or even keratin treatment, you’ve been privy to formaldehyde fumes already.
During the eyelash extension treatment, formaldehyde gases are released as a by-product of curing cyanoacrylate elements present in the lash adhesive. Exposure to small amounts of formaldehyde during the lash appointment is not harmful. However, excessive exposure to formaldehyde can cause complications.
So, you might ask, is there a lash extension glue Formaldehyde-free?
The short answer is no.
Formaldehyde is NOT an ingredient of lash adhesives. It is a by-product of curing cyanoacrylate which is found in all lash glues. You will not find lash glue without cyanoacrylate.
Now, some types of cyanoacrylate will emit more formaldehyde fumes than others so it is important to choose a quality lash adhesive that will reduce exposure to a maximum while maintaining a good hold for the extensions.
How Humidity Affects Eyelash Extension Adhesives
Humidity is your best friend no matter if you’re going for a lash extension treatment or doing one. Let’s cut to the chase.
Bonding between the extension and natural lash happens due to a chemical reaction between the humidity present in the air and cyanoacrylate, the main ingredient present in lash adhesives.
You should always keep the ideal humidity for your lash extension adhesive in check. That being said, the humidity conditions for all types of lash extension adhesives on the market aren’t the same. That’s why it’s important to check the instructions from the manufacturer when using such an adhesive.
For instance, one manufacturer might suggest keeping the humidity 40% and above while another might mandate humidity of 60% and above, etcetera. Lash techs not only need humidity detectors but ways to regulate it at the salon for appropriate application of the adhesive.
Higher humidity often leads to quicker solidification of the lash adhesive called ‘shock polymerization’ where the external layer solidifies too fast without letting the inside bond aptly. On the flip side, low-humidity levels might require excess time for drying.
How Temperature Affects Eyelash Extension Adhesives
Apart from humidity, heat is a crucial factor that affects drying, curing, and even after-bonding.
As a rule of thumb, lash adhesives dry fast in hot climates and slow in colder weather. Ideally, you should maintain a temperature of 200C to 220C in your lash salon. To be honest, most of the adhesive-related problems usually begin at the onset or end of summer and winter.
Moreover, keep in mind that there’s a relationship between humidity and temperature. For example, you should keep the temperature low whenever the humidity is high and vice-versa to balance the drying-curing of the adhesive.
In addition, avoid keeping heaters and air-con vents directly at your lash station. Apart from heaters, and air conditioners, you also need a humidifier as both heater and A/C dry out the space excessively.
If you’re feeling fancy, get an aroma diffuser instead of a humidifier to neutralize the odor too. Finally, get a hygrometer to ensure good working conditions with medical-grade adhesives.
How To Choose The Best Adhesive For Your Eyelash Extension Treatment
If you’re still waiting a whole 24 hours until you get your lash extensions wet after getting them, it might be time to familiarize yourself with the latest lash adhesives. From consistency to viscosity, drying time, and curing time, a lot has changed.
Before we find the right lash adhesive for you, you must understand drying is different from curing.
Drying is the initial phase of adhering where the adhesive stops being wet. On the other hand, curing is when it has completed the adhesion process. While the former takes a few seconds to complete, the latter can take a few hours.
There are three most important things to keep in mind to help you pick the best lash extension adhesive.
Slow Drying Vs Fast Drying Adhesives
Between the slow and fast-drying varieties of lash extension adhesives, each comes with its own set of pros and cons.
- Slow-drying adhesives: Slow-drying lash glues take longer to set. As a rule of thumb, you can expect 5+ seconds for the bond to set. They are less irritating when compared to fast-drying adhesives. Because these glues take longer to set, they are more forgiving for beginners.
- Fast-drying adhesives: Fast-drying lash glues will set faster, in 1-2 seconds. These adhesives are generally preferred by experienced last stylists since they can complete a full set of lash extensions much faster. However, they may cause more irritation for sensitive clients.
Strength Of Adhesion
While false lashes last not more than a few hours, eyelash extensions are designed to last anywhere from three to eight weeks. Here’s an in-depth case study conducted by Divine Lashes on how long lash extension lasts based on our 1,100 clients.
PMMA is the key to adhesion in lash extension adhesives as it strengthens and ensures the bond between the extension and the natural lash stays intact until the real lash sheds naturally.
Ultimately, you must also consider the humidity of the place you live in when choosing the right adhesive.
You might already know that eyelash extension adhesives come mostly in black or clear hues. Most of our clients prefer black adhesive because it outlines and defines the lash line like you’re wearing a bold eyeliner.
That being said, I’ve personally seen some clients develop allergies to the carbon black element. For clients with sensitive skin, the clear adhesive comes in handy.
My Favorite Lash Adhesive (#1 Pick)
When you begin looking for the perfect lash extension adhesive, you’ll come across so many options which can make you more confused than clear.
I don’t claim to have tried them all and found the perfect one.
However, I can share with you a lash glue that I have been using for many years now and experienced great results with my clients.
Pro Plus Eyelash Extension Adhesive
This lash extension adhesive from The Lash Collection provides excellent retention and 2-3 seconds of drying duration.
It produces a low amount of fumes and is generally very well tolerated by my clients. I use it for classic or volume.
How Long Does Eyelash Extension Glue Last?
The eyelash extension glue is designed to stay fixed on the natural lash until it naturally sheds. However, excessive heat, salt, chlorine, and oil can degrade this lash bond and cause it to fall prematurely in some cases as you learned in the article on Dos and Don’ts of eyelash extensions.
Most lash extension adhesives last well over 6 months without opening if you make sure to store it the right way. For those concerned with the shelf life of lash extension adhesives, the norm is 1 month after opening the bottle.
Expired lash glue isn’t hard to distinguish. Lash adhesives may seem runny, sticky, or even different in smell when they get damaged due to drastic temperature differences.
How to Make the Curing Process Faster?
Firstly, let’s distinguish the fine differences between drying and curing.
Drying is when the lash adhesive dries from the outside so that lash techs continue adding extensions after one another without the adhesive clumping multiple lashes together.
Curing is when the adhesive dries inside-out by using the moisture present in the atmosphere. It may take 4 to 24 hours depending on the adhesive you’re using to lash together extensions. That’s why your lash tech might warn you against getting the false eyelashes wet before the curing period is over.
There are three main things that professional eyelash technicians make use of to speed up the curing time. These methods are used at the end of the lash appointment.
Cleanse the Lashes
Cleanse the lash line with shampoo!
I know this may sound counterintuitive at first but remember that humidity accelerates the curing process. Therefore, cleansing the lashes will force the curing process.
This is my preferred method because it helps remove any chemical residue from the extensions. It is also ideal for sensitive clients.
Use a Nebulizer
Creating atomized mist particles to seep into the lash adhesive and accelerate curing, lash extension nebulizers are a great tool to have in your arsenal.
How to use a Nebulizer:
- Fill the nebulizer with tap water. Don’t use distilled water.
- Hold the nebulizer about four inches from the lashes.
- Switch on the nebulizer for 10 to 15 seconds to mist the lashes.
- Remember to remove the excess moisture between clients from the nebulizer to prevent contamination of water and mildew.
Use a Nano Mister
More popular than a nebulizer, a nano mister is easy to use manually to speed up eyelash extension curing duration. Using such a device, lash techs spray mists of fine water in a regulated manner after the lash extensions are affixed to the natural lashes.
How to use a Nano Mister:
- Select a nano-mister with the smallest particle sizes, ideally under 0.5 micrometers.
- Charge your nano mister to the full.
- Remove the rubber stopper from the water tank inside the mister.
- Add distilled water to the tank.
- Keep the nano mister at a distance of 10 to 15 inches from the lashes at an upright angle. At any point in time if you see any particle forming around the eye, increase the distance between the mister and the lash.
- Switch on the mister and let it release mist for at least 15 seconds over each eye in a swaying motion from the inner corner to the outer corners of their eyes.
- Advise the client to keep their eyes closed and mist on the top layer of the eye first.
- Now, advise your client to open their eyes and carefully mist on the bottom eyelashes.
Nebulizer Vs Nano Mister: Which Is Better?
You know lash adhesives contain cyanoacrylates but what you might not know is these are acrylic resins that don’t dry but harden only under the presence of hydrogen (as in two molecules of hydrogen in every drop of water).
Using a nano mister or a nebulizer, you can introduce fine mists that can cure extensions quickly without introducing too much humidity and dissolving the adhesive.
Because these fine mists are made of water droplets, oftentimes a timely use of a nano mister or nebulizer can soothe the eyes from harmful fumes and even prevent burning sensations, tingles, itchiness, or redness.
When it comes to accelerating the curing speed, nebulizers and nano mister are both designed to harden naturally by solidifying outside and limber or flexible inside.
A nebulizer releases mist particles that are extremely fine. Hence, it polymerizes the lash glue quickly while cooling the eyes. On the flip side, a nano mister ejects bigger droplets than a nebulizer.
If you use the nano mister for too long, you risk bleaching the lashes because of the bigger water output. This leads to the whitening of lash extensions and extremely-poor retention traits.
While nebulizer is also more silent than nano misters, they can be more pricey than nano misters. That being said, experienced lash techs say nano mister is better in climates with low humidity and nebulizers in places with high humidity.
Besides reducing the curing window from 48 hours to even 10 to 4 hours, fine mists can change the curing game completely. It’s also excellent for clients with watery eyes!
How To Use And Dispense The Lash Extension Adhesive
Lash extension fibers or fans are then dipped 2mm in the adhesive and placed on the isolated natural lash.
Get started with the three simple steps below to learn how to dispense the lash glue from the bottle.
Shake: The first step is to shake the bottle thoroughly to bring together the thickener, binder, stabilizer, pigment, accelerator, etcetera. You can shake the adhesive bottle manually before application by horizontally shaking the bottle over 30 times or for a few minutes.
Drop: When you’re pouring the adhesive onto your ring or jade stone, make sure to avoid the nozzle from touching the surface as it can contaminate the glue.
Clean: The next step is to remove the excess air in the bottle that may degrade the freshness of the glue. You can do this by burping it out gently by squeezing the body.
Now you need to remove the excess adhesive from the nozzle of the bottle using a makeup sponge or lint-free applicator so that it doesn’t clog, clump, or jam the outlet.
Finally, tighten the lid and scroll away to the next session to know how to store it without damage or depreciation.
7 Tips to Store Lash Glue
Lash adhesives are medical-grade and sensitive to heat, moisture, humidity, and other weather conditions. That’s why most lash techs keep their lash adhesive in special places. Take a minute to go through our comprehensive list of things to keep in mind when storing eyelash extension glue.
- It’s best to store the adhesive bottle inside an airtight container in a dark space. To avoid any chance of moisture damaging the glue, keep a packet of silica gel or rice.
- NEVER ever keep your lash extension adhesive in the freezer, let alone the fridge. It’s best to keep it at room temperature to avoid hot/cold shocks.
- To ensure the ingredients of the adhesive mix well, shake it for two to three minutes before using it.
- It’s best to isolate the natural lash before dipping the extension in the adhesive.
- Don’t brush the adhesive onto the lash line because it can cause adverse reactions if it comes into contact with the eyes or skin.
- Sometimes lash adhesives tend to create a whitish tint on the lashes called ‘frosting’ or ‘blooming’. It’s a result of the adhesive drying out ahead of its time. You can prevent it by misting or fanning the lashes during the application or skipping out on the primer altogether.
- If your adhesive looks like it has separated, the heat or moisture has gotten to it. It’s time to say goodbye!
How long does eyelash extension glue take to dry?
It takes from 4 to 24 hours for the drying and curing process of eyelash extension glue to be completed. However, this of course depends on the type of adhesive used and environmental factors such as humidity, temperature, and airflow.
Which glue not to use for lash extensions?
Lash glue that doesn’t contain cyanoacrylate is typically never used for lash extensions. Cyanoacrylate is a compound that’s specifically designed to create strong bonds, and it’s the main ingredient that keeps your lashes in place.
What glue is used for lash extensions?
Most professional lash artists will use a fast-drying, medical-grade adhesive that is specifically designed for eyelash extensions. This type of adhesive polymerizes in a few seconds allowing the lash tech to quickly apply the lashes. DIY lash extensions will usually require a slower-drying adhesive.
The Bottom Line
Eyelash extension adhesives are a key consideration if you want beautiful lash extensions that will last for a long time. Choosing the wrong type of adhesive can lead to poor extension retention or even an allergic reaction, so it’s important to have the knowledge you need before making a decision.
The key takeaway here is that lash techs use adhesives made of cyanoacrylate derivatives only because it’s designed to adhere to human tissues and hair.
Cyanoacrylate is a mix of thickening (cyanide) and hardening (acrylic resin) agents. There are several types of cyanoacrylates but ethyl, butyl, and alkoxy are the most common additives to lash adhesives.
Each variety differs by its drying time, curing time, consistency, humidity levels, etcetera, and different eyelash extension types may demand different adhesives.
Formaldehyde is a by-product of the curing process of cyanoacrylate. While small amounts are released during a lash appointment, some people may have sensitivities and experience an allergic reaction.
Have we missed something about eyelash extension glues that you’re confused about? Ping us below with a comment and I’ll clear it up right away!
– Asako 🙂
Further Readings on DivineLashes.ca: If you want to know more about lash glues and possible interactions, check out my guide to help recognize an allergic reaction to eyelash extensions and learn how to treat red eyes from lash extensions. Also, my eyelash extension 101 article is a great place to get started. Lastly, make sure to check my best lash glues recommendations.
- Diana N. Pei, PharmD, Certified Specialist in Poison Information. Is Eyelash Glue Toxic?. Retrieved from https://www.poison.org/articles/is-eyelash-glue-toxic-203 (Accessed on 14, January 2021)
- Emma Stoye (2013). Cyanoacrylate. Retrieved from https://www.chemistryworld.com/podcasts/cyanoacrylate/6261.article (Accessed on 14, January 2021)
- American Cancer Society. Formaldehyde. Retrieved from https://www.cancer.org/cancer/cancer-causes/formaldehyde.html (Accessed on 14 January, 2021)