The main ingredient for Eyelash extension glue is Cyanoacrylate. Mostly, its molecules are dispersed in liquid phase. However, when it comes into contact with the moisture, molecules combine instantly and it causes a polymerization and becomes macromolecules which is used as an instant glue. Of all the different types of glues, this is the only one-component glue that can be hardened under the circumstance genuinely and the typical glue that dries and reacts with humidity.

✅ Cyanoacrylate 90~95%
✅ Complex Compound 5~10% (Stabilizer, Thickener, Hardening Accelerator, Colorant, etc.)

[Principles of Hardening Eyelash Extension Glue]
Step1. The stabilizer in the glue prevents adhesive molecules from combining. Step2. When the adhesive is exposed to the air, the Stabilizer combines with moisture on the surface of the object. Step3. The adhesive molecules that have been prevented themselves from combining because of the Stabilizer, polymerizes and then forms a polymer.

Eyelash extension glue contains not only cyanoacrylate that is for adhesion, but also other complex compound such as stabilizer, thickener, hardening accelerator, pigments, and so on. Then, there will be a layer separation caused by a difference in the density of each component. It is necessary to shake the glue in order to ensure the performance and retention evenly.

If you don’t shake the glue sufficiently, the color of the glue might look like it faded away as it contains various complex compounds such as cyanoacrylate for the adhesion, pigments, and so on. It is necessary to shake the glue in order to ensure the performance and retention evenly.

If you see a layer separation even though you have shaken it sufficiently more than 1 minutes, it can be a manufacturing problem that can happen once in a while. If that happens, check the item with the manufacturer with the LOT number that is usually at the bottom of the products.

Compared to other pigments, Carbon Black can be colored with a small amount. It is most commonly used not only in eyelash extension glue, but also cosmetics such as eyeliners, mascaras, eye shadows, and so on.

Carbon Black is a soot that is produced from incomplete combustion of carbon containing materials, such as coal, petroleum, wood, and so on. WHO(World Health Organization) classified this material as a Category 1 carcinogen. If inhaled for a long time, it can cause a pulmonary function insufficiency and a cognitive decline. It can be absorbed not only from the respiratory system, but also from the skin. Also, it can accelerate the skin aging. As a result, it is avoided using this material in the products that come into contact with the skin directly, such as eyeliners, eye shadows, and so on.

As the eyelash extension glue does not come into contact with the skin, it does not have any of the problems stated above. It contains a pigment that is FDA approved. However, as some countries regulated this for export, we are replacing it. If the pigment is changed in the glue, the mix of components in the glue is changed as well. Therefore, it is replaced after the thorough safety check through the research and analysis.

📌 Methyl : Different from Ethyl, Methyl type is toxic substance. Therefore, it is strictly classified and used even for the industrial purpose. Methyl type can dissolve the proteins and lead to a permanent blindness.

📌 Ethyl : It is most used for eyelash extension glue. Its drying time is fast and the adhesion is strong, but the odor and irritation are quite strong. It is widely used for industrial, medical, and general household use.

📌 Alkoxy : It is 8 times more expensive than the Ethyl type. It is developed as a hypoallergenic and low odor type product.

📌 Butyl : Instant adhesive that is made for hypoallergenic and low odor aimed at the use of medical and veterinary. Compared to Ethyl, its drying time is slower and the adhesion is weaker. It is mostly used for medical adhesive or thickener in cosmetics. Butyl type has good adhesion, but hardens after drying. Octyl type will be softer(tension) after drying. (N-Butyl2, 2-octyl, Isobutyl, etc.)

📌 Methoxy : It is the least irritating and odorless among all the Cyanoacrylates.It is developed to improve the problems caused by the irritation and odor of Ethyl and Butyl type glue. Its drying time is slower and the adhesion is weaker, compared to Ethyl and Butyl type glue.

Of all the different types of eyelash extension glues use Cyanoacrylate which is the only one-component that can be hardened under the circumstance genuinely.

There is no other substitute glue that can replace the retention and adhesion of current eyelash extension glue.

Temperature, humidity, applied amount, applied thickness, surface condition of the bonded area, level of chemical contamination, gap sizes(hair type and degree of damage), pressure(after the adhesion), light intensity and wavelengths, and so on.

Primer is a very important product and must be used before the extension, as it helps to bind molecules. If you apply extension lashes on your natural lashes without removing oil or contamination (fat, cosmetic residue, external pollution), extension lashes will combine with those oil or contamination instead of sticking to natural lashes. Therefore, the adhesion and retention will dramatically decrease.

In countries or seasons that are very hot, oil needs to be removed more thoroughly. Wipe the lashes 2 or 3 times with people who have oily or damaged eyelashes, as those eyelashes tend not to be wiped easily.

1) Due to Materials: Compatibility of extension lashes and glue, Deterioration of glue performance, inappropriate storage method and use of products, etc.
2) Due to the Extension Methods: Incorrect attachment, Re-use of once failed extension lashes, Adjustment of glue amount, inexperienced use of pretreatment, etc.
3) Due to Customers: Customers who haven’t had extensions before, inexperienced aftercare, Conditions of eyelashes, Health conditions, Use of oil-based products, etc.
4) Due to the Environment: High temperature and high humidity, Cold and dry environment, Rapid temperature difference, Procedure in a non-ventilated place, etc.

In addition, there are number of factors that affect the retention of eyelash extensions, including conditions of technicians.
If you have problems with the retention of eyelash extensions that are unusual, it is recommended to check these factors.

There are a number of factors that decrease the retention. (Refer to number 9, Causes of the adhesion and retention decrease) Among those factors, there are two major ways to improve the retention.

To begin with, it is most important to adjust the amount of glue and then attach the lashes correctly with the accurate technique. Secondly, the appropriate use of care products. By removing the oil on the eyelashes before the procedure and using coating agents after the procedure, it can help improve the retention.

Techniques are the most important part, but it is also very important to know the correct directions of care products and use them accordingly.

The adhesion and components of glue do not change from -50 to +60 Celsius degrees. However, it is recommended to maintain 22 to 26 Celsius degrees for uniform viscosity and drying time.

If the temperature is high, the viscosity of glue gets thinner and the drying time is shorter. If the temperature is low, the viscosity of glue gets thicker and the drying time is longer.

As the eyelash extension glue reacts and dries with humidity, the drying time is closely related to the humidity. Its recommended appropriate humidity is 45 to 60%. Therefore, a uniform drying time is maintained when the uniform humidity is maintained (Range of 40~70%). The higher the humidity, the shorter the drying time and time of use after the discharge. On the contrary, the lower the humidity, the longer the drying time and time of use after the discharge. However, if the humidity is over 70%, the drying time of glue will be slower again.

Let me give you a concrete example. BL’s DIU glue has 2 to 3 seconds of drying time. If the humidity is 45%, its drying time is 3 seconds and if the humidity is 60%, the drying time is 2 seconds. Even if the humidity exceeds 60%, the drying time will not be faster than 2 seconds. Instead, the drying time will be maintained at the speed of 2 seconds for a while and then it will gradually slow down after 70% of humidity.

If you are aware of the glue hardening reaction according to the humidity, you can perform a uniform procedure under any environmental conditions.

There is no glue that is not affected by humidity since Cyanoacrylate, a component reacts with moisture and dries, is the main component of the glue. Whereas temperatures affect the viscosity of the glue, so it has less influence than the humidity.

Of all the BL glues, Ultra Plus, Ulbon, and Q-1 glue are the least affected glues from damages from the oil, moisture, and external environment.

Whichever glue you use, it is important to adjust the optimal temperature and humidity. Use an air conditioning system or a fan in order to lower the temperature. Also, equip a dehumidifier or desiccant and ventilate regularly so that you can lower the humidity. By doing so, you can adjust the temperature and humidity. Finally, choose the glue according to your preference after that.

However, in hot and humid areas or weather, excess amount of oil is secreted on the skin and eyelashes. Therefore, it is recommended to use a glue that is resistant to water and oil, or to use the one that has low viscosity. Also, before the procedure, remember to remove the oil on eyelashes thoroughly. If the natural eyelashes are damaged, the oil tends not to be removed clearly. Thus, it is important to remove it 2 to 3 times before the procedure.

Humidity tends to be high in hot countries and seasons. Also, the viscosity tends to get thinner due to the high temperature. Therefore, it is recommended to use a glue that has a bit of viscosity rather than the low viscosity one.

✅ Recommended glue : DIU (2~3seconds/experts), Q-1 (4~5seconds/intermediates & beginners)
✅ Water and oil resistant glue : Q-1 (4~5seconds) Ultra Plus (3~4seconds), Ulbon (4~5seconds)

Whichever glue you use, it is important to adjust the optimal temperature and humidity. By using a heater, you can increase the temperature. Also, use a humidifier in order to adjust the temperature and humidity. Then, choose the glue according to your preference. If you still have a difficulty in increasing the humidity even with the above efforts, you can have the uniform treatment by choosing a lower viscosity glue or faster drying glue.

Below 0 Celsius degrees, be aware that the impact strength of glue is deteriorated. However, if it is maintained at the room temperature after heating or cooling for a short amount of time, there won’t be any change of qualities of the substances.

Ex) Humidity tends to be low in cold countries and seasons. Also, the viscosity tends to get thicker due to the low temperature. Therefore, it is not recommended to use a glue that has high viscosity. Otherwise, you can choose a glue according to the procedure speed.

✅ Recommended glue : MACH (1~2seconds/experts), Ultra X, Ultra +(plus) (3~4seconds/intermediates), Ultra Bonding, Ulbon (4~5seconds/beginners)

**If you do not prefer a low viscosity glue, you can use DIU, Fina, or Q-1 as the viscosity of them is higher than the recommended glues.

It is impossible to compete for superiority of the glue because it is sensitive to the treatment environment, proficiency of the technicians, and so on. Decide the best glue for each technician by considering the treatment environment, speed of the procedure, and so on. For example, if the technicians use 1~2 seconds of drying glue when they take 3~4 seconds to apply extension lashes on natural lashes, the retention will inevitably decrease because the extension lashes are applied on natural lashes after the glue is already a bit dried. Another example would be as follows; If the technicians use the slow drying glue when their speed of procedure is faster than that, it is not an appropriate glue as well because it will interfere with the procedure. In addition to these, adjust the procedure environment if the technician is living in a country where there is a big difference in weather or humidity and temperature. If it is hard to do so, it is recommended to use a glue that is suitable for the situation in order to keep the uniform retention and procedure.

Based on the classic extensions under the circumstance of appropriate temperature (22~26 Celsius degrees) and appropriate humidity (45~60%)

✅ Experts : MACH, DIU
✅ Intermediates : Ultra X, Ultra +(plus), Fina
✅ Beginners : Q-1, Mild, EZ, Ultra Bonding, Ulbon

**The above recommended glues are the guideline according to the drying time and they are not absolute. Thus, it is better to choose a glue according to the movement of the technician, procedure environment, characteristics of the clients, preferences of the technician, and so on.

Volume extension glues can be divided into two main categories; for handmade volume glue and premade volume glue.

For handmade volume lashes, as you need to make a fan, it is recommended to use a fast drying glue or the one that has a bit high viscosity. MACH glue is suitable for those who are fast when applying extension lashes. Glam glue is suitable for those who want a glue that has longer drying time.

For Premade volume lashes, it is recommended to use a glue that has fast drying time and low viscosity. This is because the adhesion parts of premade volume lashes are wide and glue can be applied excessively on those wide areas which will result in surrounded lashes sticking to them. MACH glue is suitable for those who are fast when applying extension lashes. Ultra X or Ultra Plus glue is suitable for those who want a glue that has longer drying time.

Currently, it is hard to make a quick-drying glue with the hypoallergenic and low odor cyanoacrylate base. Although hardening speed can be increased by adding a hardening accelerator called ‘Toluene’, it is not used in BL Lashes because Toluene is harmful to the human body.

The instant glue basically becomes a solid acrylic like plastic after hardening. The surface might withstand certain amount of water, but the sealing effect of the bonded area itself is not very good. Thus, it is hard to call it a water proof or oil proof.

Eyelashes do not fall off immediately when they come into contact with water or oil. However, the strength of the adhesion drops dramatically due to the hydrolysis. 

2 to 20 seconds after the extensions, the hardening progresses more than 93 to 97%. Hence, it has little possibility of forming Efflorescence once they are dried 1 to 2 minutes with the fan. However, the possibility of forming efflorescence increases when the amount of glue is excessive as the hardening takes more time.

It takes about 24 to 48 hours for glues to be dried completely. Therefore, it is recommended to use a serum or coating sealants after 24 to 48 hours from the extensions. (Other companies are selling coating sealants or serums, telling it can be used right away. It might not cause a problem as written above immediately. However, always be aware as the glue is not hardened completely, it can affect the retention adversely.)

✅ 3 to 6 months when not opened, 1 month once opened.

When the glue is contained in its bottle, it is hard to harden because the surface area that is in contact with the air is small, compared to the capacity of the liquid. However, once it is applied to the material, as the surface area becomes wider, the hardening reaction becomes active and the whole area hardens in sequence.

Since the hardening of glue is always in progress, its function is kept on deteriorating even if it is not opened and used. The period from the moment it is manufactured to the state of unavailability is called the ‘expiration date’. It is important to keep the appropriate temperature and humidity and pay attention to the storage methods in order to prolong the expiration date.

Eyelash extension glue is a reactive type adhesive. Therefore, it is important to manage the environment in the treatment room and the storage area. The glue will not deteriorate at temperatures within -50 to 60 Celsius degrees. Hence, store it where it is cool and dark, avoid from the direct sunlight and high humidity instead of storing it in the refrigerator.

When storing it, the deterioration of the glue is depending on the humidity rather than the temperature. Therefore, as long as the humidity is low, it can be stored in a place where the temperature is high. However, be aware that, in most of the high temperature areas, humidity is high as well.

BL Lashes glue has a desiccant in the zip-lock bag together, in order to prevent the performance deterioration of it, which is caused by moisture. When storing the glue, put the glue container with the desiccant together as it was manufactured and store it upright with the zipper sealed. In order to manage the glue effectively, write down the purchase date and an opening date on a glue zip-lock bag.

In order to use the glue for a long time, pay attention to the precautions and storage methods.

1) When discharging the glue, lift the outlet from the surface slightly as the dust or dirt may be sucked in the container.
2) Wipe the glue nozzle with a piece of paper immediately after use.
3) Close the lid tightly and seal it instead of just placing a lid on it in order to prevent the contact with moisture.
4) As it was manufactured, store the glue in a sealed zip-lock bag with the desiccant.
5) Store it in a dry and cool place, avoid from the direct sunlight.
6) In humid season or environment, you can purchase extra desiccants in the glue zip-lock bag. By doing so, you can prolong the expiration date.

All eyelash extension glues are cyanoacrylate-based adhesives. Therefore, the storage method is the same.

Glue hardens by the reaction with moisture in the air. The most stable storage place is in the dark and cool place. Refrigerator is not an appropriate storage place as it can affect the performance of glue adversely by causing a dew condensation, not only on the outside, but also on the inside. In the past, a dry place that can be easily found was a refrigerator which absorbed moisture. However, it is not recommended as it keeps and supplies the moisture nowadays. If you must use refrigerator inevitably, seal it as much as possible when storing and put it on the room temperature at least for 2 hours before use.

If the temperature of the glue storage place is below 60 Celsius degrees, it is recommended to use a dehumidifying box which has a function of dehumidification.

The lower the humidity, the longer the glue will stay fresh.

✅ Shake side to side, more than 20 times before use, in order to eliminate the precipitation.
✅ Discharge the glue on a glue plate film by turning the bottle upside down (90 degrees).
✅ After the use, clean the glue smeared nozzle with a piece of paper. (Do not use tissues or cotton pads that might have fibers on them, as they can contaminate the nozzle and deteriorate the performance of glue.)
✅ Discharge a new droplet of the glue every 20 minutes.
✅ Put the glue with the desiccant in a zip-lock bag and store them vertically.
✅ It is hard to be hardened in cold environment. Thus, it is better to use on a glue plate. (Use from the middle part because it hardens from the outer part)
✅ During the procedure, adjust the amount of glue so that it doesn’t flow through eyelashes and contact with the mucous membrane.
✅ Sensitive customers might experience glue side effects. Therefore, proceed the extensions with sufficient counseling. (For short-term allergy tests, either apply a small amount of glue on the back of the ear or extend 5 to 6 strands and check the progress 20 to 30 minutes later. For long-term allergy tests, check the above progress 24 hours later.)
✅ As the glue is contained in a special container(bottle), do not transfer contents to an ordinary plastic or glass container.
✅ when storing it in a refrigerator, put it on the room temperature at least for 2 hours before use.

You cannot affix some materials with the instant glue, such as Silicone, Urethane, PE, PPE, Teflon, and so on. Among them, PE is the most commonly used for the glue container. The materials and the shapes of the container are very important as the instant glue rapidly reacts with the traces of moisture in the air. Generally, PE is not used solely. Instead, it is made of laminated structure with Nylon. Since glue is manufactured using a special container like this, please do not transfer the contents to an ordinary plastic or glass container.

Eyelash extension glue might expand and explode, if it is contained in a hermetically sealed container. Therefore, it is impossible to contain it in such containers. Hence, do not transfer the contents to an ordinary plastic or glass container, as eyelash extension glue is manufactured with the special container.

Cyanoacrylate reacts with the traces of moisture in the air or on the adhesive surface, and then hardens instantly.

When it is contained in its container, it is hard to harden because the surface area that is in contact with the air is small, compared to the capacity of the liquid. However, once it is applied to the material, as the surface area becomes wider, the hardening reaction becomes active and the whole area hardens in sequence.

If the glue becomes stickier than usual, stretches like a thread, or the hardening takes longer than before, then the performance is already deteriorating. Therefore, it is better to discard the glue even if there are some contents remained.

Since the hardening of glue is always in progress, its function is kept on deteriorating even if it is not opened and used. The period from the moment it is manufactured to the state of unavailability is called the ‘life time(expiration date)’. It is important to keep the appropriate temperature and humidity and pay attention to the storage methods in order to prolong the life time(expiration date).

The clogging of the discharge port is caused by gas or bubbles that are generated in the container when discharging. And then, the bubbles rise with glue and form a layer at the entrance of the outlet. If the glue layer is visible at the entrance of the outlet once opened, the layer must be removed by discharging it. This way, it prevents the outlet from clogging, but it also keeps the glue fresh for a long time by removing the glue layer that is exposed to the air.

It can also happen when the glue bottle is kept on its side or when it is shaken vertically instead of side to side. In this case, use a glue pin that is contained with glue to pierce the clogged hole.

This happens when *the particles (Monomers of small molecular weight, such as methyl or ethyl cyanoacrylate, are vaporized in the air and polymerized into short polymers that are incompletely grown by moisture in the air.) are absorbed on the adhesive area. -> This is used for fingerprinting.

This is mainly caused when the glue comes into contact with the pre-treatment which is not dried during the procedure, or with the customer’s tears when the glue is not dried. It can also happen when the serums or coating sealants are used right after the extensions while the glue is not dried completely.

2 to 20 seconds after the extensions, the hardening progresses more than 93 to 97%. Hence, it has little possibility of forming Efflorescence once they are dried 1 to 2 minutes with the fan. However, the possibility of forming efflorescence increases when the amount of glue is excessive as the hardening takes more time.

Usually, glue dries(hardens) completely 24 to 48 hours later. Therefore, avoid using coating sealants and serums for 2 days after the extensions.

Molds and germs cannot reproduce in glue. It is the polymer (Efflorescence) that is seen as white powder in the container.

Eyelash extension glue might expand and explode, if it is contained in a hermetically sealed container. Therefore, it is impossible to contain it in such containers. Hence, do not transfer the contents to an ordinary plastic or glass container, as eyelash extension glue is manufactured with the special container.

As the glue might expand and explode if it is contained in a hermetically sealed container, it is contained in a special container to allow a small amount of air to pass through. Therefore, even if you close the lid tightly, the glue is likely to deteriorate after 3 to 6 months.

As the glue hardens in contact with moisture, gas is generated, and at this time, the traces of glue are mixed in the gas. Glue has a tendency to settle on moisture and oil. The particles are absorbed on the moisture and oil in the glue container (hand held part), making them look white. -> This is used for fingerprinting.

As the glue hardens, gas is generated, and at this time, the traces of glue are mixed in the gas. Glue has a tendency to settle on the moisture and this causes irritation in the presence of moisture. As a result, it causes sore eyes because there are tears on the surface of the eyes.

Some technicians wipe the glue onto the eye patches during the procedure, in order to adjust the amount of glue. This should be avoided as it can irritate the eyes more because the glue hardens on the surface of eye patches.

If the customer tears during the procedure, there is a high possibility that their eyes are not closed completely. Therefore, dry those tears with a fan and proceed the extensions after checking their eyes thoroughly.

If they still have problems with irritation, it is better to use hypoallergenic glue. Technicians can reduce the irritation by wearing a goggle and mask. If you put BL’s anti-allergy gel right next to the glue, you can reduce the irritation more dramatically.

Although there may be short-term sore eyes and bloodshot eyes due to the glue irritation, cyanoacrylate is not toxic unlike ordinary cyanide materials. It is not accumulated in the body and completely decomposed and discharged out of the body in about 2 months. As a result, it is used as a medical adhesives.

A sty is caused by infections of the lachrymal glands and auxiliary glands of the eyelids, mainly by staphylococci. Since the germs cannot reproduce in the glue, it is not caused by the glue itself. As it is an infectious inflammation, it is more likely to be caused by unsanitary hands or contaminated treatment environment (tools, subsidiary materials) rather than troubles result from the glue. Always make sure to disinfect your hands and tools before the procedure and pay attention to keep dust from accumulating on subsidiary materials such as extension lashes and tapes. Also, do not touch the extension lashes and glue plate with your hands.

If the extension lashes are extended to multiple strands of natural eyelashes instead of single strand or attached with the downy hair, it may be irritating or itchy. It is important to check the lashes after the extensions, to see if there are any attached eyelashes beside. Your eyes may also feel irritated when it is attached to the mucous membranes instead of away from the skin, or the lump is on the lashes due to the excessive amount of glue.

Otherwise, it can be caused when the treatment environment is not clean or the customer is immunocompromised due to the bad condition. Therefore, always keep the treatment environment clean and check the customer’s condition.