If you want to be a cosmetic chemist and make cosmetic products, there is certain essential equipment that you’ll need to get.

Here is a list of the basic equipment for setting up a cosmetic lab.

Basic cosmetic Lab equipment

1. Weighing equipment. To make proper measurements of the raw materials, you’ll need a good balance. Be sure to get one that can measure up to at least 500g.

Other weighing equipment that helps includes disposable pipettes (for measuring liquids) and weigh boats (for measuring solids).

2. Containers. The most common container you’ll use to make a cosmetic formula is a beaker. You’ll need a variety of sizes because you’ll be making different sized batches. Be sure to have a number of 500mL, 800mL, 1000mL, 1500ml and 2000mL beakers. You really want 400g to be the minimum size batch you make.

3. Mixers. In college, you most frequently used a magnetic stirrer to mix your creations. These are rarely used in a cosmetic lab. For mixing, you’ll want an industrial type mixer, something like the Lightnin mixer. It is like a single blade hand mixer with a variable speed control. Quite handy.

4. Controlling Temperature. Most cosmetic formulas require heating and cooling so a good hot plate is a must.

Sometimes you can air cool batches but for things like emulsions, you’ll want to have a water bath for cooling it down quickly. This could simply be a tub you fill with cold water and ice.

5. Testing equipment. After you’ve finished a cosmetic formulation, you’ll need to test it to ensure that it meets specifications. For this, you’ll want to have a pH meter and a viscometer (for measuring rheology).

Of course no cosmetic lab would be complete without a good stock of cosmetic raw materials. Which of these you have will depend on the type of formulas you make. Everyone will want to have a supply of deionized water. Most will also want to have a stock of common preservatives, acids, bases, and dye solutions.

Fortunately, if you work for a company they’ll have this stuff for you. They’ll also have more specific equipment for the types of formulas you’ll mostly be working on. However, if you are setting up your own lab or helping your company get into the field of cosmetic science, be sure to stock your lab with the proper equipment.

What equipment do you use for cosmetic formulations? Leave your comment below.

Innovation from the cosmetic raw material companies always makes me smile. I remember when one particularly “innovative” company would come in for a visit and always show these incredible compounds with mind blowing claims. While I always admired their attempts there was a fundamental thing they did that I found troubling; they would blur the line between cosmetic claims and drug claims.

I still frequently see this with the way both cosmetics and cosmetic raw materials are marketed. So, I thought it would be helpful to go through what is a cosmetic.

What is a cosmetic?

Let me first apologize to our International readers. This article will focus mainly on the US market. However, many of the same principles apply.

According to the FDA a cosmetic is…

“articles intended to be rubbed, poured, sprinkled, or sprayed on, introduced into, or otherwise applied to the human body…for cleansing, beautifying, promoting attractiveness, or altering the appearance” [FD&C Act, sec. 201(i)]

And to distinguish cosmetics from drugs, the FDA further defines a drug as…

“articles intended for use in the diagnosis, cure, mitigation, treatment, or prevention of disease” and “articles (other than food) intended to affect the structure or any function of the body of man or other animals” [FD&C Act, sec. 201(g)(1)].

What does this mean?

The key piece to consider is the part in the definition where it states “…articles intended to affect the structure or any function of the body of man…”

So, when companies make claims like…

Ingredient will stimulate collagen production

Ingredient will inhibit the enzyme tyrosinase

Ingredient will prevent premature gray hair

…they are making DRUG claims, not COSMETIC claims. If you use these ingredients in your formulation with the intent that they are going to have the effects claimed, you are no longer making a cosmetic. You are formulating a drug that is regulated differently than cosmetics. (Mostly, it requires more testing and validation).

What is not a cosmetic?

So to simplify the difference between cosmetics and drugs think of it this way.

A cosmetic is a product that is designed to clean or alter the appearance of the skin and hair without affecting metabolic processes. Body wash, skin moisturizers, make-up, etc. are all cosmetics as long as they are not intended to ‘stimulate collagen production’ or otherwise interfere with natural body processes.

When is a cosmetic a drug?

There are some products that are both cosmetics and drugs. This would include products like anti-dandruff shampoos, toothpaste, antiperspirants, sunscreens and anti-acne treatments. These products have to comply with the rules governing both cosmetics and drugs.

Innovation in the cosmetic field is difficult because cosmetic chemists are restricted in what type of effect they can have on the body. If you have created a formula that affects the normal functioning of the body’s cells, then you are no longer formulating a cosmetic, it’s a drug. Until they change the rules, things called cosmecuticals are just marketing fluff.

In the United States (and most other places around the world), beauty product manufacturers are required to list the ingredients used to make their products in a specific way. The current guidelines can be found on the FDA website here – FDA Cosmetic Labeling.

Since it isn’t a terribly interesting read, we’ll try to summarize the key points here. We’ll also explain to you how ingredient listings can be useful to cosmetic formulators.

Cosmetic Ingredient names

We previously wrote about how cosmetic ingredients get their names so go read that for more details. Basically, the names come from the INCI Dictionary. These are the names that are supposed to be used by everyone although some manufacturers might take liberty with their labels and include inappropriate terms (e.g. ‘purified’ water)

Order of listing

In this post on how to label cosmetics, we gave an explanation of the rules in which ingredients are supposed to be listed. Essentially, things in concentration above 1% are supposed to be listed in order of concentration and things at 1% or lower can be listed in any order. Colors are supposed to be listed at the end.

Where to find cosmetic ingredient names

When you are working with a raw material, the supplier will have the INCI name listed in the specification sheet. Often, raw materials are made up of multiple compounds so there will be a listing of multiple INCI names. To create the correct ingredient list, you have to know the % of each compound in the raw material. This can get complicated and we’ll save the topic for another time.

Sometimes the INCI names are pending (if it’s a new material) but you should generally avoid working with raw materials that don’t already have an INCI designation.

If you are searching for a raw material, a nice, free way to find them is via the INCI directory. This excellent resource was created by Specialchem4cosmetics.com and is really helpful.

Where to find ingredient lists

Now that you know how to decipher raw material lists, you need to get some so you can start using them. Of course, an obvious place to get ingredient lists is to go to the store and get products. They should be listed there right on the back of any personal care and cosmetic product.

But going to the store can be inconvenient and you can often get ingredient lists just by searching the Internet. Two excellent sources of cosmetic ingredient lists is Drugstore.com and Ulta.com. The best thing about these sources is that they also include the cosmetic claims which can also be helpful.

How to use ingredient lists

Alright, now you have an ingredient list and understand what it means, you might be wondering, so what? Good question.

Here are a few things that I’ve used ingredient lists for as a cosmetic chemist.

1. For copying competitor’s formulas – Copying (or knocking off) a competitive formula is a great exercise for any new cosmetic chemist. It gives you a great sense of what the raw materials do, which ones are important, and how they affect different performance characteristics. There is no better teacher than going through the trial and error process of copying a formula from an ingredient list.

Remember to use the few clues that you have. For example, identify the probable 1% line, do a % solids test to figure out how much water is in the formula, and take pH and viscosity readings to figure out your targets. Then make some prototypes and see how close you can get.

2. For new product ideas – Marketers are always looking for new ingredients so whenever you come upon a novel ingredient, write it down, learn about it and pitch it at the next new product meeting if you wish.

3. To learn new ingredients – Whenever you see an ingredient you don’t know, take the time to look it up. Figure out why it might be in the formula. This way you can use ingredient lists as a way to help build your cosmetic science vocabulary. When you were learning to read they told you whenever you read a word you didn’t know the meaning of you should look it up in the dictionary. Well, whenever you see a raw material you don’t know, look it up in the INCI dictionary.

Have you found useful ways to use ingredient listings? Leave a comment below and let everyone know.

“What does a formulation scientist do every day?”

This was a question I received in an email from someone who was doing some research about different chemist careers. And if this person wanted to know about it, it makes sense that some of you might be wondering the same thing. So, here it is, 75 things that a formulation scientist or cosmetic chemist might do on any given work day, conveniently presented in four categories.

Cosmetic product development

Create formulas
Gather raw materials
Get equipment for making batches
Make batches
Restock lab supplies
Keep notes in notebook
Write experimental results in notebook
Clean glassware and lab
Research formulation topics
Generate new product ideas
Create prototypes
Create dye solutions for color matching
Make samples for marketing
Supervise / make batches for home use tests
Supervise first production batches
Solve stability problems
Generate test ideas to substantiate claims
Figure out ways to make formulas less expensive
Attend focus groups
Participate in brainstorming meetings
Review product label copy
Assist in writing product concepts
Present new technologies to non-scientists

Cosmetic product testing

Take pH readings
Take viscosity readings
Fill and label glass and plastic bottles
Wash & comb hair tresses
Color matching
Bleach and color hair tresses
Conduct foam tests
Run stability tests
Conduct skin moisturization tests
Run project specific, customized tests
Try formula prototypes
View samples under a microscope
Observe salon tests
Conduct odor tests
Participate in product panel testing
Get samples for testing
Evaluate competitive products

Personal Training

Read trade journals
Read Chemists Corner and other useful blogs in your RSS reader
Attend meetings with suppliers
Go to SCC meetings
Go to industry trade shows
Take continuing education courses
Attend conferences
Review latest patents
Listen to podcasts like the Chemists Corner podcast
Read industry text books
Take online training courses
Pursue an advanced degree in cosmetic science

Business stuff

Respond to emails
Create presentations
Attend corporate meetings
Attend project planning meetings
Respond to phone calls
Do desk side interviews with beauty editors
Conduct training sessions for non-scientists
Write business travel reports
Fill out expense reports
Write monthly reports
Go to office celebrations
Engage in “water-cooler” chat with co-workers
Write memos
Sign and review contracts
Give instruction to people who report to you
Meet with your boss to update them on your progress
Interview candidates
Entertain kids during Bring Your Kid to Work week
Keep track of project progress
Engage in debates with regulatory & legal departments
Write patent applications
Write employee reviews

Whew! My brain is fried and I might be able to go on, but I think I covered practically everything I did as a cosmetic chemist.

Is there anything we missed? Leave a comment below

One of my favorite times when training new cosmetic chemists is the moment they learn that many of the ingredients cosmetic companies put in their formulas are added for reasons other than their direct function. The look of puzzled enlightenment when they realize that the beauty product marketing they’ve accepted thus far is exaggeration is…well…priceless.

Perhaps by the end of this post, you might experience that look too.

What are puffery cosmetic ingredients?

In the cosmetic science business, non-functional ingredients that are added to your formula to support marketing stories have a variety of names; puffery ingredients, featured ingredients, woofle dust, and pixie dust have all been used to describe these ingredients. They usually have some of the following features.

1. They sound impressive
2. They provide a story that consumers find compelling
3. The are trendy and probably featured in a magazine article
4. They are endorsed by some “expert”
5. They are expensive
6. They are used at low levels

Basically, these ingredients are added to help convince consumers that their beauty product is special and will provide miraculous results.

Which of these sounds more compelling to you?

“Our product combines a blend of naturally charged biominerals with powerful botanical ingredients to create an exclusive anti-aging technology”

Or

“Our product combines petrolatum with cetyl alcohol to create an exclusive anti-aging technology”

Obviously, the first one. But the truth is, the functional claims of this product are provided by ingredients like petrolatum, mineral oil and cetyl alcohol. They just don’t sound as good.

Examples of puffery ingredients

There are a wide variety of cosmetic ingredients that are added as puffery ingredients but they roughly fall under one of the following types.

Vitamins – Everyone knows that vitamins are good for your diet and you need them to live, but consumers also have the erroneous belief that if something is good to eat, then it’s good to put on your skin & hair. The truth is there is very little evidence that topically applying most vitamins to your skin will have any effect. (Vitamins A & C are exceptions and can have an effect if properly formulated). There is no evidence that vitamins in your hair care products will have much effect. Some claim Vitamin B can increase hair strength but I’m not convinced by the available science and my own experience.

Whether they are functional or not, adding vitamins makes your cosmetic products more appealing to consumers

Proteins – These are another type of compound that consumers know about and are naturally inclined to believe they are good for them. When eaten, they are good for people. When slathered on their skin and hair, not necessarily. Proteins like collagen and elastin are added to skin creams. Silk, keratin, and other exotic hydrolyzed proteins are added to hair products. These ingredients aren’t added because of the effect they have (they don’t do much). They are added because consumers and marketers like the stories they convey.

Natural ingredients – Some beauty product companies are so enamored with natural ingredients, they add dozens and dozens which make their ingredient statements look like novellas. These include extracts from all kinds of plants from fruits, vegetable and herbs, taken from exotic places in the world like the Amazon rain forest or the mountains of Switzerland. You’ll find things like marine extracts and organically grown strawberry extract. If it’s natural and someone can squeeze some juice out of it, someone might ask you to put it in your formulas.

These ingredients rely on a belief in folklore to convince people they do something. More often than not, they are non-functional.

High tech ingredients – Sometimes marketers like to impress consumers by telling them a high tech story. To help support this story, you’ll be asked to add things like Stem Cells, Nanosomes, or ingredients with completely made-up high-tech sounding names. As with the other puffery ingredients, these high tech wonders frequently have some science to back up the story but almost never to back up their functionality delivered from a product.

Is cosmetic ingredient puffery right?

Admittedly, ingredients like this have always made me a little uneasy. It seems like trickery and worse, like lying. But the truth is, people who buy beauty products do not always want the “truth”. They don’t want to think that chemicals like Sodium Lauryl Sulfate or Petrolatum are what really makes their cosmetic products work. They would rather like to believe in the story that it’s Aloe that moisturizers their skin or it’s the Coconut Oil that gently cleanses their hair.

This is what people buy.

Whether we like it or not, as a cosmetic scientist we are in the business of creating great, functional products that people buy. If you create a brilliant formula that no one ever purchases, you’ve failed. Puffery ingredients entice people to buy products.

The ethical cosmetic chemist

Here are a couple of guidelines to use when adding pixie dust ingredients to your formulas.

1. Stay honest with yourself. Be careful not to fall for your own story. If you think the great high-tech ingredient you’re adding to your formula is really making a difference, be sure to conduct a blinded, placebo controlled study to see what effect it really has.

2. Stay honest with your marketing people. Your marketing department desperately wants a product they can tell consumers is vastly different (and superior) to the competition. They will believe the marketing of other cosmetic companies. Resist the temptation to mislead your marketing group by telling them that these puffery ingredients will actually have a significant benefit. In the vast majority of cases, they won’t.

3. Always make great products. Don’t use the stories available from puffery ingredients to cover-up some low quality formulation. It is your responsibility as a cosmetic chemist to create the best formulas you possibly can.

See this article for more on what the FDA has to say about cosmetic puffery.

What do you think, is it right to add ingredients to your formulas that you know are not adding a functional benefit? Leave a comment below.

It’s the latest episode of the Chemists Corner podcast.  Please have a listen and let us know what you think.

Chemists Corner podcast is about cosmetic science and is broadcast to help educate, entertain, and inspire current and future cosmetic scientists. Each episode we’ll talk about news in the cosmetic industry, answer some of your questions, and discuss a topic in-depth, usually with an industry expert interview.

In this episode…

1.  News

• Colorado Safe Personal Care Products Act – The state of Colorado is proposing a bill that could limit the cosmetic chemist’s ability to formulate.

2.  Listener question – How do you do a Freeze / Thaw stability test?

3.  Cosmetic Science - Top 10 problems in hair care science

4.  Interview – Amanda Foxon-Hill of Realize Beauty.

• Amanda Foxon-Hill is a longtime cosmetic chemist who’s worked in both Europe and Australia. She has experience formulating a wide range of products and is currently the Director of Realize Beauty, which features a website dedicated to de-mystifying the cosmetics industry for the consumer. She works as an instructor for the Institute of Personal Care Science which offers a certified diploma course in cosmetic chemistry. Additionally, she runs workshops called Cosmetic Kitchen for adults and kids where they make a few basic products. Her latest project is writing a book called “Realize Beauty” which is a philosophical look at our relationship with our bodies.

5.  Weekly Challenge.

Perfume manufacturers are bringing out new fragrances for the coming season.

Ralph Lauren has four new fragrances, Christian Dior has five, and Givenchy has two.

How many new fragrances will be promoted by Yves Saint Laurent?

If you’ve got an answer to the challenge, have a question, or have any topics you’d like us to cover, leave a comment below.

Formulating is one of the most enjoyable aspects of being a cosmetic chemist. This is when you get to blend all the cosmetic science you’ve learned with your creative inspirations. It’s how you can make your mark as a formulation chemist.

The following 6 steps will help you take your ideas and convert them into functioning cosmetic products.

Step 1 – Define your product

Before you get started, you need to think about what you are going to make. Figure out what functions you want your product to achieve. Is it a cleansing product, a moisturizer, a coloring product, or maybe a combination of factors? Also think about the aesthetic characteristics like color, thickness, clarity, etc. and the cosmetic product form. Write these parameters down so you’ll know when you done whether you’ve been successful.

It is always helpful to have a target product with characteristics that you are trying to match. Be sure to get a sample to look at and feel.

Step 2 – Find a starting formula

Next you need to figure out a good starting formula. Starting formulas can be found from a variety of sources. You can look at some of the most useful cosmetic science books. You can also look at online formularies like the one from Happi.com or Chemidex.com. Raw material suppliers like Croda and Rhodia also have formularies that you can use. Another useful source is patents. You can use Google patents or the USPTO.gov website to find formulas. Of course, you can also talk to a colleague who may be able to share one of her starting formulas with you. Finally, if you work at a big company, they will have a big archive of old formulas that will give you a great starting basis.

Remember, starting formulas are not meant to be finished formulas

Step 3 – Prepare for your batch

Once you have your starting formula, you’ll want to determine how much you want to make and create a spreadsheet which lists out how much of each ingredient you need. Then you’ll need to list the specifications that you will test when the batch is finished. After that you’ll have to gather up all the raw materials and processing equipment needed to make the batch. Next, put on your safety glasses & start making your batch.

Step 4 – Making the batch

Making a cosmetic product is much like cooking. You weigh or measure out your ingredients, mix them together as dictated in the procedure and heat & cool as required. During the entire process you should be writing detailed notes and observations in your lab notebook. These will come in handy when you need to make refinements for future prototypes.

You almost never make a perfect batch on your first try

Step 5 – Test your batch

Once you’ve finished your formula, you’ll want to test it to see how successful you were. After letting the sample equilibrate to room temperature, take appropriate measurements like pH and viscosity to see if you are within specifications. Also, weigh the batch to see how much water weight you lost during the heating and cooling process. If you’ve lost more than a few % of water you may want to add water to make up the difference. In addition to specification tests, you should also do some performance tests to see how well the product functions. At the very least try the product on yourself. If the formula meets your satisfaction then you’ll want to do a stability test.

If you won’t use the product you made, why should anyone else?

Step 6 – Revise formula and Repeat

After you’ve tested the product and determined where it doesn’t quite measure up, you’ll need to make adjustments to see if it can be improved. I’ve found that knockout experiments are the most helpful way to figure out the effect that every ingredient has on the final formula. Once you know what the ingredients do, you’ll know which ones to increase or decrease to improve your formula.

After a dozen or so revisions, you should have a formula that meets your needs.

Cosmetic formulating is as much an art as it is a science. As you gain more experience, you’ll find ingredients that you like to work with and others that you avoid. You’ll develop your own style and ideally make products and formulas that are genuinely unique to you. I always liked to add a “signature” in my formulas by using some ingredient at a % that included the number 44. It didn’t usually have much affect on the formula but it did make me feel like the formula was my own creation. And it was.

Good luck in your formulating career!

As a cosmetic chemist you will undoubtedly be asked to make products that require you to combine materials that aren’t easily compatible.   Fortunately, there is a system that can help you get started.

Cosmetic Emulsions

Emulsions are one of the most common forms of cosmetic products. You find them in skin lotions, make-up, and even hair products. By definition an emulsion is a dispersion of two or more immiscible materials, where one phase, also know as the internal phase, is dispersed in the continuous or external phase. Cosmetic emulsions are classified as oil in water (O/W), water in oil (W/O) and water in silicone (W/Si). Multiple emulsions such as oil in water in oil (W/O/W) are also possible. Oil in water emulsions are the most common due to preferable cost and light skin feel.

In order to create an oil in water emulsion (one that remains stable for a long enough time), work must be done to overcome the interfacial tension between the two phases. This can be achieved by mixing; however mixing even at very high rates is not enough to provide long term stability.  An emulsifier or combination of emulsifiers is needed to stabilize droplets of the dispersed phase.  For example, simple oil in vinegar salad dressings will separate rapidly without the use of an emulsifier like mustard.

Using Surfactants

In this industry, we use surfactants to create emulsions. Surfactants are molecules that have a hydrophobic (oil soluble) and an effective hydrophilic (water soluble) portion. They act as emulsifiers by significantly lowering the interfacial tension and decreasing the coalescence of dispersed droplets.

HLB Formulating

Figuring out what surfactant to use for any specific formula will be a challenge you face as a cosmetic chemist. There is a great deal of research on surfactants and their behavior. But studying the thermodynamic equations and phase diagrams associated with surfactants can be a daunting task, not to mention the number of surfactants available to the formulator is vast. Luckily for us, William C. Griffin developed a way to streamline the selection of surfactants by utilizing the ratio of the hydrophobic to the hydrophilic portion of the molecule.  This method is referred to as the HLB (Hydrophile Lipophile Balance) method. Griffin first presented this method at meeting of the Chicago Chapter of the Society of Cosmetic Chemists in 1949 and it is still widely used today. He published the method shortly there after.¹ (A bit of trivia for you, the Chicago Chapter was the first chapter formed in Society of Cosmetic Chemists)

The HLB method applies to nonionic (uncharged) surfactants but attempts have been made to broaden the concepts to other surfactant types including silicone surfactants. And using the HLB system to create emulsions is quite simple. All you have to do is calculate the HLB number of your surfactant, then the Required HLB for the oil phase and match the two numbers.

Determining the HLB of a surfactant

A typical nonionic emulsifier (e.g. Laureth-4) contains an ethylene oxide groups or polyhydric alcohol hydrophilic portions with a fatty alcohol hydrophobic portion. The HLB for a nonionic surfactant can be calculated as follows:

HLB = Weight % Hydrophile/5

Example 1: HLB calculation for Laureth-4

Molecular weight of ethoxylate portion = 176

Molecular weight of lauryl alcohol = 186

Wt. % Hydrophile = (176/(176+186)) x 100 = 48.6%

HLB = 48.6/5 = 9.7

Based on the calculation, surfactants with high HLB values will be more water soluble and those with low HLB values are more oil soluble. Division by 5 just allows for a compact, easy to use scale. The calculation is simple, but you won’t usually have to figure it out since most surfactant HLB values are readily available through literature references and surfactant suppliers.

Calculating HLB of oil phase

Each lipophilic ingredient in the oil phase has its own required HLB. These required HLB values are determined experimentally, however a method utilizing solubility parameters has been proposed by Vaughan and Rice.² Required HLB values for some common oil phase ingredients are available to the formulator in literature. The Req’d HLB values are approximate and can vary by about ± 1 unit. It is also important to keep in mind that cosmetic emulsions often have complex oil phases with several components. The required HLB of an oil phase mixture can be calculated by first calculating the percent of the oil phase each ingredient contributes. This percentage is then multiplied by the required HLB for each of those ingredients and the results are summed.

Example 2: Calculation of required HLB for an oil phase mixture

The oil phase is 10% of the total formulation and consists of:

4% Shea butter, 40% of the oil phase. Req’d HLB of 8.

3% Jojoba oil, 30% of the oil phase. Req’d HLB of 6.5.

3% Sunflower seed oil, 30% of the oil phase. Req’d HLB of 7.

Total required HLB:

Shea butter contribution 0.4 x 8 = 3.20

Jojoba oil contribution 0.3 x 6.5 = 1.95

Sunflower oil contribution 0.3 x 7 = 2.10

Total Req’d HLB = 7.25

You can now select emulsifiers to match the required HLB of the oil phase and create an emulsion. A blend of high and low HLB surfactants is often used to achieve the desired value in part because of demonstrated effectiveness and efficiencies in packing at the interface. The HLB for the surfactant blend is calculated in same manner as the required HLB for a blend.

Example 3: Calculation of HLB for a surfactant mixture

The surfactant mixture is a 70/30 blend of Steareth-2 and Steareth-21.

Total HLB:

Steareth-2 contribution 0.7 x 4.9 = 3.43

Steareth-21 contribution 0.3x 15.5 = 4.65

Total HLB = 8.08

In order to match the HLB of a particular oil phase, it is easiest to set up a spreadsheet with the calculation and vary the percentages of each emulsifier in increments of 5% to find the right ratio.

Limitations of HLB

Although a very useful tool, the HLB system does have some limitations. For example additional water phase ingredients are not considered but still may impact the stability. The method also does not provide information as to how much surfactant is needed, but 2 to 4% surfactant is a good starting point to begin further optimization for stability. So it is important to keep in mind that the HLB system is not absolute in prediction of your formulations behavior, but a very good starting point for achieving emulsification.

References

1. Griffin WC; Calculation of HLB Values of Non-Ionic Surfactants, Journal of the Society of Cosmetic Chemists; 1954. Vol. 5, pp 249-235

2. Vaughan, C.D. Rice, Dennis A.; Predicting O/W Emulsion Stability by the “Required HLB Equation”; Journal of Dispersion Science and Technology; 1990. Vol. 11 (1), pp 83 – 91.

There are many different routes you can take to learn to become an expert formulation chemist but few are more powerful than conducting your own knock-out experiments. These type of experiments can help you learn a number of things such as,

• 1. The function raw materials
• 2. The performance effect of raw materials
• 3. The formula effect of raw materials

It can also potentially lead to the discovery of a new formulation and cost savings ideas.

Formulation Chemist Knockout Experiment

The term knockout experiment was taken from the field of genetic engineering. In it, scientists create organisms in which they remove or “knock out” a specific gene. Then they see what effects the removal of a certain gene has on the organism.

In the cosmetic chemist’s version of a knockout experiment, you take a known formula and “knock out” a specific raw material. You then see what effect the absence of that raw material has on the final product. It’s a simple yet powerful study that can quickly get you familiar with any formula.

What will a cosmetic knockout experiment teach you?

When you first start your cosmetic formulating job, you will often start new projects with a formula that your company had previously developed. I remember the first formula I ever made (a shampoo) was originally developed by the guy whose notebook I inherited. My boss asked me to make samples to give to our Marketing group for evaluation. I had no clue about why any of the raw materials were used, what they did, or even how hard they were to work with.

You will undoubtedly be in the same position if you are just starting in this industry. Even if you’ve been around for a long time, it’s impossible to know the effect of raw materials in any formula you haven’t personally made (or observed being made).

Knockout experiments can rapidly tell you when making a batch exactly which ingredients have the most effect, which ones can be removed and which ones interact. When you’re done making the formulas, you can learn what raw materials have the most impact on the final specifications and the product performance.

The amount of information you can learn from a single knockout study makes it well worth doing on every new formula you are asked to work on.

How to conduct a cosmetic knockout experiment

Running a knockout experiment is fairly easy. All you have to do is take your initial formula and make a series of batches in which you remove one ingredient. If it’s a water-based formula, you simply add water to replace the missing mass.

Here is an example batch sheet for conducting a knockout experiment on a shampoo formula.  (Click to enlarge) As you can see, each subsequent formula has a line where the value of one ingredient is supposed to be.

In this formula there are 8 unique ingredients which means you will need to make 8 different batches. The first batch is the control batch which should be made first. This ensures that you are able to successfully make the formula.

You should try to control as many variables as possible such as temperature, mixing speed, mixing time, etc.

Simplifying the knockout experiment

While it is best to make a new formula for each ingredient, this can become impractical and unproductive if there are dozens and dozens of different raw materials. In these cases you can minimize the number of batches to make by ignoring ingredients not expected to significantly impact the end performance such as

• 1. fragrance
• 2. dye
• 3. extracts
• 4. preservatives

If you don’t know which ingredients are superfluous, ask one of your more experienced peers. But be careful. It is wrong to make any assumptions about a formula. There could be ingredients you expect not to have any effect that do.

It’s worth noting that more complicated versions of this knockout experiment can be conducted using DOE (design of experiment) software. These experiments can give you much more information. Unfortunately, they also require many more batches to be made. In future articles we will discuss DOE further.

Evaluating your cosmetic knockout formulas

After you’ve made your batches you will end up with a series of formulas that need to be tested. At the very least you should take pH and viscosity measurements. You can then correlate the presence of any ingredient with an effect on those variables. This can be extremely useful if you need to help make adjustments on the production level in characteristics like pH, viscosity, texture, odor and appearance.

You should also conduct appropriate lab tests to see how the removal of a certain ingredient affects performance. For foaming products, conduct foam tests. For skin lotions, do a moisturizing test. Perhaps most important is to try the product out on yourself. Try to experience the product like a consumer. This will give you excellent clues about how important any raw material is to the overall effect of the formula.

Knockout your cosmetics

The knockout experiment is not a perfect way to learn all you can about a formula. There are important synergistic effects it will miss. That’s why DOE is often superior. However, you can’t beat knockout experiments for speed and ease. And you’ll definitely learn a lot about raw materials quickly. To become a great formulation chemist you have to make a lot of batches and try many different ingredients. The knockout experiment helps get you there faster.

This recent article about scientists discovering bacteria living in hairspray provides a good example of why cosmetic products need to be preserved. Microbes can grow almost anywhere! And these tiny organisms bring with them some distasteful product changes or even disease. As a cosmetic chemist it’s up to you to formulate properly and keep these invaders at bay. You typically do that by adding preservatives to your formulas. Unfortunately, you’ll have to know more than just the science as preservatives are some of the most highly regulated and restricted ingredients you will use.

Why you need cosmetic preservatives

There are two primary reasons you need preservatives.

1. To stop microbes from spoiling your products.
2. To stop microbes from causing disease.

The microbes that can infect your formulas primarily include bacteria, mold, and yeast. In small quantities they don’t represent much of a problem but when they multiply, look out. Bacteria like Pseudomonas can cause all kinds of health problems including skin and eye infections, toxic shock, strep throat, and even food poisoning. Yeast like Candida albicans can cause thrush. And many other bacteria can cause your products to smell awful, change color or otherwise break down. (This is what stability testing is for).

The following is a list of common preservatives used in cosmetic and personal care products. As a future (or current) formulator, you will undoubtedly be using many of them.

Parabens

Parabens are the most commonly used preservatives. They are derivatives of p-hydroxybenzoic acid and go by names like Methylparaben, Propylparaben, and Butylparaben. They are typically supplied as powders and can sometimes be difficult to incorporate into a system due to the water solubility limitations. They are effective against a broad spectrum of bacteria and fungi. They do have pH limitations and are not effective against all microbes so you usually will need an additional preservative.

Formaldehyde donors

Formaldehyde derivatives are the next most common preservative. These compounds interfere with membrane proteins which kills microbes. They are effective against bacteria, fungi, and mold. Bad press and real safety concerns have led cosmetic chemists to stop using formaldehyde. Instead ingredients that dissociate into formaldehyde when put in a water solution are used. These are compounds like DMDM Hydantoin, Imidazolidinyl Urea, and Gluteraldehyde. They are most often used in surfactant systems.

Phenol derivatives

Phenol derivatives have been used in cosmetics for many years and can be effective against a range of microbes. Unfortunately, they are not as effective as the previous ingredients so their use is limited. The most common examples is Phenoxyethanol.

Quats

Compounds that contain nitrogen and have a positive charge when placed in solution are called quaternary compounds (or quats). Many of them demonstrate an ability to kill microbes. This include ingredients like Benzalkonium Chlroide, Methene aommonium chloride, and Benzethonium chloride. Their cationic nature makes them less compatible with anionic surfactants which limits their application & use.

Alcohol

Ethanol is a great preservative but you need to use it in high levels and it faces significant environmental restrictions. Other compounds like benzyl alcohol, dichlorobenzyl alcohol, and even propylene glycol all have some anti-microbial effect. In lower levels, these compounds are less effective at preserving products.

Isothiazolones

Synthetic compounds like Methylchloro- Isothiazolinone and Methyl-Isothiazolinone are effective at incredibly low levels. They have been shown to work at a wide range of pHs and in many different formulas. There use has been stymied however, by at least one study that suggested it could cause skin sensitization.

Organic Acids & Others

Various other compounds are used as preservatives but all face some limitations not experienced to the same extent as the previous ingredients discussed. Some of the most important include Sodium Benzoate, Chloracetamide, Triclosan, and Iodopropynyl Butylcarbamate. Pyridine derivatives like Sodium pyrithione and zinc pyrithione are used to kill the bacteria that causes dandruff.

Why cosmetic preservatives are vilified

More than any other ingredient, preservatives are most often called out as the worst ingredients you can use in a formula. Even people who know nothing about chemistry have likely heard about the “evil” parabens and formaldehyde.

Preservatives are designed to kill cells. That’s why they are effective. Unfortunately, that’s also why they are potentially hazardous. They don’t easily discriminate between good human cells and bad microbial cells. But ultimately, the risk from using preservatives is significantly lower than that of using unpreserved cosmetics. There are safe levels of “toxic” chemicals. All chemicals can be deadly if you’re exposed to a high enough level. How many people die from water exposure (e.g. drowning)?

Remember, it’s the dose the matters!

To be sure, cosmetic science research is ongoing in the field of preservatives since many things previously deemed safe have been reclassified as hazardous. Suppliers who can come up with even safer preservatives will likely make a lot of money. Hopefully, they’ll do it soon but there do not appear to be any promising materials on the horizon.