In chemistry, pH means “potential of hydrogen” – the concentration of hydrogen ions in a solution. It’s a scale used to specify the acidity or basicity of the solution. 

Pure water has a pH of 7, considered pH neutral; all other solutions are compared against that pH level. Solutions are measured at 25 degrees Celsius: a pH of less than seven is considered acidic, and solutions with a pH greater than seven are considered basic or alkaline. 

In a normal state, our bodies (skin, eyelashes, eyebrows, etc.) have a pH value of about 5.5, which is slightly more acidic than water-neutral pH, which is called “body neutral pH.” Body neutral pH is therefore 5.5-7 meaning any solution up to 7 is still neutral to our bodies:  

Changing the pH level of lashes or eyebrows opens their cuticles and allows us to make permanent changes in their shape. 

What’s the difference between pH neutral and pH balanced?

A pH of 5.5-7 is considered “neutral” since it’s the pH of water.

Healthy skin, eyelashes, hair, and nails pH is around 5.5. So, any cosmetic product with the same pH level of 5.5 is considered pH balanced. Using pH-balanced cosmetics daily is recommended because they don’t change the pH of skin, eyelashes, hair, and nails. Any pH different from 5.5 impacts skin, eyelashes, hair, and nails. The bigger the difference between the pH of the cosmetic product and skin, eyelashes, hair, and nails, the more impact the product has.


Alcohol is widely used in lash & brow products due to its main valuable properties:

  • Opens lash & brow cuticles
  • Strips lashes, brows, and skin from natural oils
  • Speeds up adhesive curing speed
  • Can lower pH

The downside is that alcohol is very aggressive – it damages cuticles and even burns some cuticles off! Since cuticles lock in moisture inside lashes and brows, damaging them means lashes (or brows) become dehydrated and brittle.

Alcohol also makes cyanoacrylate more porous. This means using alcohol-based products during treatments will make your lash adhesive emit more vapors. This means that your lash adhesive fumes (the most irritating part of lash glues) will irritate your customers more than they would if you weren’t using alcohol-based products. Which, in the long run, will increase the likelihood of your customers developing a sensitivity/allergy toward lash adhesive.

This effect is readily observable if you pour alcohol on your glue dot. Look for the whitish color and cracks:

Alcohol also makes cyanoacrylate more brittle. This means that when your customers touch their extensions with their fingers or brush them, the glue bond will more likely break, losing retention.

Because of this, I don’t recommend using products that are alcohol based (that means that they have a high % of alcohol in them). Unfortunately, alcohol-based products used to be the only option in our industry, and many lash artists still use them. However, nowadays, you can choose products that achieve the same goal without harmful side effects.

The main alcohol-based products used in the lash industry that safer alternatives should replace:

Heating Mask

Disposable or re-usable (USB-charged) heating masks can be used for lash and brow lifting treatments to make the lotions work more efficiently. However, they may only be used for products with a very gentle formula, as adding heat to aggressive products will most likely over-process lashes. Use it ONLY if the manufacturer has confirmed that their products are ok to use with heat.

NB! Since heating masks make all lotions work more efficiently, be mindful of lifting lotion processing times as they usually need to be reduced when used with a heating mask


NB! Some products require heat to perform like they are supposed to. For example, keratin products need heat from 38-41 degrees Celsius (100-106 degrees Fahrenheit) to activate keratin’s beneficial properties!

Chemistry of Lash/Brow Lift Products

As lashes and brow hairs are very similar in anatomy, you can apply the following chemistry information to both eyelashes and eyebrows. 

To curl lashes permanently so that the curl doesn’t drop in the presence of water or heat, the cuticles of the lashes must first be opened and pH raised (the result of the curling lotion stage). Then pH was brought back to as neutral as possible, and the cuticles closed as much as possible (effect of the fixing lotion).  

All Lash Lift procedures in the world are based on the same principle: 

  1. Changing the pH towards alkaline with a curling lotion to open the cuticle scales and break down disulfide bonds.
  2. Then restoring the pH and disulfide bonds with fixing lotion and closing the cuticles.

Chemistry of Lash Primers

Primers have a dual purpose – to remove natural oils and to open lash cuticles. They are very effective in achieving these goals, but the problem is that alcohol (the main active ingredient in primers) is very aggressive. Just think about how your skin feels when you pour alcohol on it. If you haven't experienced this, I highly recommend giving it a try as it teaches a lot about alcohol's effect on the skin and, therefore, on lashes/brows – notice how quickly it evaporates and how dry your skin feels afterward. 

Primers fulfill their purpose in just 1-2 seconds, and while they achieve their goals fast, they do hurt lashes because they are so aggressive that they burn off some of the cuticles, and these cuticles will never grow back. In addition, the burnt cuticles mean lashes will be left dehydrated after primers use. 

Also, because alcohol evaporates so quickly, primers only have the time to cover some cuticles evenly. So what happens is that when you apply primer onto lashes, the parts of the lashes that you touch first will get a strong hit of alcohol, open to 100% in a second or two. Then some cuticles that are further away (for example, lower level cuticles, bottom layer lashes if you start applying from the top, and top layer lashes if you start applying from the bottom row) don't get primed. So some cuticles will open 100%, but some only like 75%, some halfway, etc., and some don't open. That is if you apply a regular amount of primer. If you add a lot more, then all cuticles will be soaked and open 100%, but also, a lot more cuticles will be burnt off, never to grow back, and lashes will be super dehydrated afterward.

Lifting lotion (also known as curling lotion)

The purpose of the lifting lotion is to make lashes super soft (like cooked spaghetti!) to give them a new shape with fixing lotion. Lashes mainly consist of keratin, so the lifting lotion must contain ingredients that split the disulfide bonds in the keratin to make it possible to give lashes a new shape. Due to this, the curling lotion is the most aggressive product of all lotions used during lash lifting and can cause the most damage if misused.

The harsh ingredients in lifting/curling lotions are often used to break down keratin. Usually, a mixture of them is used to achieve the desired result:

  • thioglycolate
  • ammonium bicarbonate
  • anything with ammonium in the name
  • ethanolamine

Different proportions of these ingredients and how they are mixed together determine how aggressive or gentle a specific curling lotion is for natural lashes. There are MAJOR differences between the effect aggressive and gentle lash lift products have on natural lashes!

The only thing that all lash lift or ‘lamination’ products have in common is that the pH of the lifting lotion is at pH 8.1 – 9.5. Under a pH of 8.1, the lotion does not break down keratin easily as it’s too close to neutral pH, and from pH 9.5, the cuticles start ‘burning’ = which means dying = that’s where hair removal begins. I had a pH of 7.9 for my lifting lotion a while ago. However, I realized that this only provided beautiful results when the tiniest amount of adhesive was used, so I changed the pH slightly higher for the products to always give a nice effect, even when using more glue.

Can lash lift curling lotion be used on eyebrows too?

Since lash lift curling lotion (the only aggressive product in the lifting process) has been developed not to touch the skin, it may NOT be used on eyebrows! There is a horrendous trend where some brands claim that their curling lotion suits eyelashes and eyebrows. It is ONLY a marketing ploy – it leaves skin under and around the eyebrows red and irritated. It can cause brows to look wonky or even break off. Remember – curling lotions include harsh chemicals such as thioglycolate, ammonia, and ethanolamine in proportions that are ok to use on hair but not on the skin. 

Brow lamination products have to be a bit stronger on the hair yet softer on the skin than lash-lifting products to lift the brows and not cause damage to the skin. The skin around the eyebrows SHOULD NOT BE RED/IRRITATED after the lifting process! The only irritation that’s ok during brow lamination is from waxing/threading/plucking. If you see redness after lifting, you should reconsider the products you are using as it damages the skin, causes dehydration and flakiness, and may cause brow hairs to fall out!

Fixing Lotion

The purpose of fixing lotion is always to neutralize the pH and close lash cuticles as much as possible and, therefore, “fix” the new shape of the lashes. This is very important to understand because this means that the shape of lashes or eyebrows (during brow lamination) is NOT crucial during the lifting phase when they are soft like spaghetti. It’s important to keep lashes and brows (during brow lift) in the correct position during the fixing stage = if any lashes pop off the rod before you remove the fixing lotion, they will NOT be curled, as well as the rest of the lashes. To achieve a sleek look during brow lamination, pressing the cling film down tight during the fixing stage is essential, not perming. 

Since the purpose of the fixing lotion is to restore disulfide bonds in the lashes by neutralizing the pH, it is not an aggressive product. Therefore the same fixing lotion may be used for eyelashes and eyebrows during brow lifting.

Usually, sodium bromate or hydrogen peroxide is used to fix lotion ingredients to fix the new shape and close the lash cuticles. Simply, the effect of sodium bromate/hydrogen peroxide can be compared to that of a hair conditioner after shampooing. 

Does it make a difference whether sodium bromate or hydrogen peroxide has been used? 

Yes, it does make a difference as these ingredients break down into different compounds after they have done their job. For example, sodium bromate breaks down into acidic bromate salts that stay on the lashes even after the treatment is over, and this has a dehydrating effect on the lashes. This is the reason higher quality brands use hydrogen peroxide instead – the disintegration of hydrogen peroxide (H2O2) only produces H2O (water) and O (oxygen):

NB! Sodium bromate is also banned in cosmetic products in several countries, such as Italy and Canada. If you live in those countries, make sure you do not use a lash lift brand that uses it in their fixing lotion, as your insurance will not cover you if you use products that contain illegal ingredients!

Most fixing lotions close cuticles down to about 70% on average which is slightly less than most people’s average before any lifting treatment.

This is why most lash brands recommend not getting lashes wet for 24h after the treatment – until cuticles are at least as closed as before. This is because lashes and brows are sensitive to the outside environment and can change shape. It takes lashes and brow hairs to naturally close cuticles to their normal state about 12-24h after the lifting treatment. After that time, the lift is “set” and will no longer be affected by the outside environment, like heat and water. 

After the setting time, a lash lift can not drop unless the hair is treated again chemically – this is the whole point of lash lifting. So if your customers tell you that their lift has “dropped” after a few weeks, it has, in fact, just grown out and not dropped.

Lash Chemistry: what are the differences between various lash lift brands?

All the lash lifting and brow lamination products in the world have one main character to determine them – how damaging or healthy they are for lashes and brows. You might think that the difference is not that big, but the products differ like night and day! A good comparison is about bleaching your hair at a professional hair salon or at home. Yes, the result of both is blonde hair, but your hair's state is VERY different, depending on the products used. 

It's the same when doing lash lifting with gentle VS aggressive products – they both lift lashes, but the former leaves lashes dehydrated and has a great potential of over-processing lashes; the latter only takes a little bit more time but leaves lashes looking healthy, shiny and not prone to break.

Where does the difference come from?

As mentioned before the key player is the curling lotion, the most aggressive stage of lash lifting. Aggressive products have very short processing times as they are so strong that they only need a little time to penetrate lashes fully and completely break down disulfide bridges in the lash keratin. Then, they shock lashes to open cuticles, raise the pH in just a few seconds and soften disulfide bridges in just a few minutes. All of this puts a huge amount of stress on lashes, and the state of lashes after that stage is like night and day compared to gentle products (remember the hair bleaching comparison). 

What damages lashes is: 

  • pH shooting up in seconds: the quicker it rises, the more damaging it is to natural lashes 
  • the pH of the curling lotion: the higher the pH, the worse it is for natural lashes 
  • the quality of the ingredients: the lower the rate, the more damaging it is to natural lashes 
  • over-processing happens when lashes are at a heightened pH level for too long 

More gentle products need more time to achieve the same thing gently. For example, our curling lotion: 

  • Rises the pH in about 3 minutes (instead of seconds) 
  • The pH of the curling lotion (and therefore the pH of lashes during the curling stage) is lower (ours is currently at 8.4). The special formulation of the curling lotion brings the pH down to neutral after about 15mins, so there is no risk of over-processing. After about 15mins, the curling lotion has no further effect on the lashes.

When you work with aggressive products, it is paramount to time curling lotion processing time very precisely as keeping it on for even 1 minute too long may over-process them. However, when working with gentle lash/brow lift products, you can test different processing times without worrying about over-processing lashes/brows!! 

How do I know how aggressive or gentle is the brand I’m working with?

There are a few telltale signs: 

  • Processing times: the shorter the processing times, the harsher the products. NB! This does not automatically mean that products with longer processing times are automatically gentle! 
  • Processing times are exact. Lashes get over-processed easily if the curling lotion processing time is one minute off. With gentle brands, you can safely test different processing times. 
  • The smell of the curling lotion: ammonia has a very distinct rotten egg smell, so the nastier the lotion smells, the more ammonia or its derivates it usually contains 
  • Products that come in larger containers than just 1-3 treatments: if your curling lotion comes in a regular small bottle that you can open and close again without the pH dropping, it is STRONG. Gentle lotions are oxygen sensitive and are packed in airless pump bottles. 
  • The manufacturer recommends taking a break after a few lifts to give lashes a chance to restore. When we were testing our curling lotion, we did FOUR lash lifts in a row without the model even getting off the bed to check the state of the lashes after that. And you know what? There was NO DAMAGE to lashes whatsoever! Your customers never have to take a break from lifting treatments when they have been performed with Ruthie Belle products. 
  • Customers must use a home care product to hydrate and nourish lashes and brows. Without it, lashes/brows look dry and wonky. With gentle lash lift products, customers don’t have to use anything extra at home besides their regular beauty routine. They can do it, of course, if they want to do something good for their lashes, but it is not mandatory, and their lashes will not end up looking weird if they don’t

I also made a Youtube video that explains this: ignore the difference in the pH level compared to the picture in the blog, as the video is much older, and we’ve changed the formula since. 

What is a “keratin lash lift” and is it nourishing for lashes?

"Keratin lash lift" usually means that keratin has been used as one of the ingredients in more products than just the last nourishing step of the treatment. It is often advertised as a "nourishing" treatment for your lashes, implying that the inclusion of keratin in the curling or fixing lotion makes the whole treatment somehow "healthier" than "regular" lash lamination (referring to curling lotions without keratin).

Firstly, keratin needs heat to be activated, so for any of those products to offer keratin's benefits, they would have to be used only with a heating mask. 

Secondly, harsh chemicals such as:

  • thioglycolate
  • ammonium bicarbonate 
  • anything with ammonium in the name 
  • ethanolamine 

…neutralize (remove) the effect of those nourishing agents in the curling lotion, which means that including keratin in the curling lotion doesn't make much of a difference.

So the only way a "keratin lash lift" can be better than a "regular" lash lift is when the curling lotion is: 

  • Truly organic (meaning without these aggressive ingredients) 
  • Supposed to be used with added heat 

If one of those conditions is not filled, the added keratin in the lotions doesn't make any noticeable difference to lashes or eyebrows.

Lash Serums

The working mechanism of lash serums is to artificially elongate lash growth cycles and thus make lashes grow longer than they naturally would. After you stop using the serum, lashes will return to their normal growth cycle – that's why it's common to shed a lot of lashes initially after stopping the serum. 

Lash growth serums were invented when people noticed that the medication for glaucoma (eye pressure condition) made lashes grow longer. Bimatoprost is one of those medications, so initially, people who wanted longer lashes would use bimatoprost as a lash serum. However, soon after it was discovered the dangers of this practice – it not only made eyelashes grow longer but also:

  • Changes the pressure in otherwise healthy eyes
  • Changes the color of the iris
  • Enlarges veins in the eye area (on the eyelids)
  • It makes the skin around the eyes look darker

Since these negative permanent side effects were discovered, it was prohibited to market prostaglandin/bimatoprost as a lash serum, and scientists began to look for an alternative solution. The problem is that prostaglandin/bimatoprost are very effective in growing lashes longer fast, so while some scientists started looking for safe alternatives, others only began to look for ways to alternate the original ingredient enough not to eradicate the dangerous side effects but only be able to invent a new component that still has these side effect but can be given a new name to get around restrictions for prostaglandin/bimatoprost.

Some companies STILL use bimatoprost or its derivates that have the same nasty side effects because they give fast results in growing lashes longer, so I decided to make an explanatory post to explain this to allow you to make an educated decision about which serum to go with and not fall for direct marketing.

The best explanation is that the derivates of bimatoprost are essential ingredients that have very similar properties to the original component. Still, since bimatoprost has a bad rep, chemists have changed its composition just enough to be able to give a new name to the ingredient but not enough to escape its adverse side effects.

The most popular prostaglandin derivates used in lash serums are:

  • Dechloro Dihydroxy Difluoro Ethylcloprostenolamide
  • Ethyl Tafluprostamide
  • Latanoprost
  • Travoprost
  • Tafluprost
  • Noralfaprostal
  • Methylamido-Dihydro-Noralfaprostal
  • Isopropyl Cloprostenate

You can recognize them in the ingredients list as they have "prost" as part of the active ingredient's name. You can also quickly identify the effect on the lashes as they grow super long but look wonky and "spidery."

Today, scientists have also invented alternative ingredients that don't have prostaglandin's side effects. They usually take about 2-3 weeks longer to achieve longer lashes but don't have prostaglandin's adverse side effects, nor do they make lashes look so crazy. 

The most popular alternatives to prostaglandin used in lash serums:

  • Myristoyl pentapeptide-17 (that's what we use in our lash serum)
  • Myristoyl hexapeptide-16

All of the serums that contain any of these ingredients make eyelashes grow. The difference is how much of the activating ingredient has been included – this decides the serum's efficiency in making lashes grow longer. Some manufacturers also add ingredients to help provide food for lashes so that they don't only grow longer but also stronger. Also, most manufacturers add filler ingredients to lash serums to bulk them up or to make them look more appealing to customers.

How to use lash serums?

It’s enough to use lash serums once a day because the active ingredient is so potent that it is enough to make lashes grow. Use it at night (after removing makeup) as your body restores itself overnight the most. Using it twice won’t make lashes grow faster. It will only deplete your product more quickly. As long as the product is full, you don’t have to double dip – there is enough product on the wand for both eyes. Double dip for the second eye only when you feel your product is getting low in the tube.

Why retail lash serum to your customers?

We recommend retailing lash serums to your lash lift customers, as it will enhance their lift's look and add to your bottom line!

However, I don't recommend retailing serums to your lash extension customers as it will only make their extensions grow out faster, not grow their lashes stronger.

The only exception is customers with super short lashes that can't hold the length of extensions that they want to go for.

This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.

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