Hair Theory 101: A Comprehensive Guide to The Science of Hair

By | July 29, 2022

Hair Theory 101: A Comprehensive Guide to The Science of Hair

Let’s speak about primary hair concept– the science of hair and the way it all works!

In magnificence college, hairstylists study all the pieces you may think about about hair. This consists of hair shade concept, chemistry, anatomy, hair construction… and even the enterprise facet of operating a salon.

Actually, all of this stuff are tremendous vitalAre you able to think about what occurs to your consumer’s scalp in the event you don’t combine the bleach accuratelyDangerousdangerous issues can occur with out the right coaching

Howeverdon’t have any worryThis text will infuse you with all the fundamental hair data you want!

So do you assume you’ve what it takes to do hair? Hold studying to seek out out…

💡TIP: Pin this text to your Hair Colour board on Pinterest so you may all the time come again when it’s worthwhile to! 👇🏼👇🏼👇🏼

There's so much more to hairstyling than you realize. Find out everything you need to know about basic hair theory with this ultimate guide.

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Hair Idea 101

Human hair under the microscope.

So what’s hair?

Hair is a filamentous biomaterial, primarily composed of Keratin. It grows from hair follicles discovered within the dermis and covers many of the human physique.

It’s additionally a novel attribute of mammals.

Hair Construction 101

Every strand of hair consists of three separate layers: the cuticle, medulla, and cortex.

Hair Structure: Cuticle, Medulla, Cortex

The Cuticle

The cuticle is the outermost layer, containing arduous, shingle-like cells that overlap one another. Its objective is to strengthen the hair and shield the inside layers.

This layer determines how wholesome your hair seems to be.

In wholesome hair, the scales lay flat on one another, giving the hair a smooth, shiny look. Quite the oppositebroken hair has raised scales, making the hair seem like tough and textured.

That being statedyou may alter the state of the cuticle in numerous methodsLet me clarify

Delicate warmth (like a towel wrapped round your head after the bathe) or acidic hair merchandise clean down the cuticle; alkaline merchandise swell the hair and lift the scales again up.

The Cuticle of Healthy Hair vs Damaged Hair

The Cortex & Medulla

Beneath the cuticle lies the cortex. This layer resides in the midst of the hair shaft and makes up the majority of the hair.

Melanin, aka shade pigment, is discovered within the cortex and determines the colour of the hair. Moreoverthe form of the cortex determines if the hair is straight, wavy, or curly.

This layer additionally holds water and keratin proteins. All chemical therapies (hair shade, perms, relaxers, and so forth.) happen within the cortex.

Final however not least, the innermost layer of the hair known as the medulla, and its objective remains to be unknown. The truth is, you gained’t even discover it in individuals with positive hair.

Now that you’ve a stable understanding of hair construction, let’s dive into hair shade concept

Hair Colour Idea 101

Hair color ranges are organized from 1-10. Stage 1 refers to black hair, whereas stage 10 is the lightest shade of blonde.

Hair color numbers/level chart system.

Colour Idea

All naturally occurring hair colours are created from completely different mixtures of the three major colourspink, blue, and yellow.

Color wheel or color circle with twelve colors

Okay, so check out the colour wheel. Do you discover that the first colours divide it into three sections? This makes it a lot simpler to visualise shade concept.

Now we are able to see the secondary coloursthat are made by mixing two major colours collectively; they sit straight between the 2 major colours on the wheel.

These colours are inexperienced (blue + yellow), orange (pink + yellow), and violet (blue + pink).

The cool factor in regards to the shade wheel is that it reveals you the way colours work collectivelythe colour that sits straight throughout from one other is its complementary shade.

That is tremendous vital with hair shade… as a result of complementary colours both intensify or neutralize one another.

So take into consideration this… when hair is bleached, it normally turns pale yellow. A violet-based toner will cancel out the yellow tones and make the hair seem platinum-blonde.

Likewise, orange hair might be toned with a blue (ash)-based toner. For this reason “blonde” shampoos are likely to have blue or purple pigments in them.

How Hair Colour Works

Two primary chemical substances present in everlasting hair shade are hydrogen peroxide and ammonia.

Ammonia separates the cuticle scales, permitting the colour to get contained in the hair; peroxide oxidizes the pigment. When hair shade penetrates the cortex, it deposits shade molecules too huge to flee.

For this reason it’s arduous to get shade out as soon as you set it in.

Bleaching hair includes an identical course of. The peroxide softens and lifts the cuticle so the bleach can go in and disperse the colour molecules within the cortex.

Developer is the peroxide element we combine with hair shade once we’re prepared to use it… and there are completely different levels of developer that every do various things.

5V and 10V (V=quantity) are deposit solelythat means they’ll’t raise the hair to a lighter shade. Due to this factyou must solely use these guys when going darker.

20V lifts as much as 2 ranges and deposits some shade. That is probably the most generally used developer and is greatest for gray protection.

Likewise, 30V lifts as much as 3 ranges and 40V as much as 4 ranges.

40V isn’t used typicallybecause it causes probably the most harm and may injure the scalp if misused; it’s usually solely used with high-lift blondes and bleach.

Forms of Hair Colour

There's so much more to hairstyling than you realize. Find out everything you need to know about basic hair theory with this ultimate guide.

When eager about what sort of shade to make use oftake into account how lengthy it’s going to final, how a lot harm it causes, and if it will probably lighten your hair or not.

Some hair colours are “deposit” solelywhereas others can “raise” your hair to a lighter shade.

  • Everlasting colours can raise hair as much as three ranges and final till the hair grows out.
  • Excessive-lift colours can raise the hair about 4 ranges; these are kinds of everlasting hair shade meant for lighter blondes.
  • Demi-permanent colours final about 4-6 weeks and ultimately wash out with no line of demarcation; these can’t raise hair to a lighter shade.
  • Semi-permanent colors solely coat the hair shaft with out penetrating into the cortex. When utilized accurately, these colours can final a couple of weeks.
  • Temporary color washes out within the bathe.

There's so much more to hairstyling than you realize. Find out everything you need to know about basic hair theory with this ultimate guide.

Colour Correction 101

So… generally your shade doesn’t prove the way you anticipatedWhat do you do then?

Whereas a number of components are at play (if the hair is mild sufficient, how even the appliance was, situation of the hair, and so forth.), hair toners can normally assist. These distinctive hair colours are designed to deposit pigment and alter the tone.

As beforehand talked aboutyou should use an ash shade to neutralize the brassy tones… or a violet-based toner to kill the yellow hues.

💡RELATED: How To Use a Hair Toner For Brassiness

Except you want yellow hair, you must all the time tone bleached hair. That is the way you get the completely different blonde shades like ash, platinum, strawberry, and so forth.


Let’s say you’ve platinum blonde hair however wish to go darker. You’re gonna wanna repigment or “fill” the hair first… in any other case, you’ll find yourself with light, ashy hair shade.

To repigment the hair, you typically wish to use reddish-gold colours which might be one stage lighter than the specified shade.

Whereas all shade strains are completely differentyou may normally discover a “repigmentation” system for the particular shade you wish to use. At all times observe the instructions for the very best outcomes.

An instance repigmentation course of: For Paul Mitchell shade, you’ll combine equal components of the formulation with 10V developer and apply to damp hair.

Course of for 10 minutes after which apply the goal shade over the repigmentation system (except the goal system is cool/impartial, then wipe off the repigmentation system first).

Course of the entire thing for a further 35 minutes, after which BAM… repigmented hair.

There’s a cause why hair shade specialists receives a commission the large bucks…

The Golden Rule of Hair Colour

A brilliant vital factor to find out about hair shade concept is that color will not lift previously colored hair predictably.

This mainly signifies that in case your hair was beforehand coloured darkish brown, and also you wish to raise it to a lighter shade, you’ll must bleach/strip your hair earlier than you may shade it.

Think about all the pieces we’ve talked about to this point… In case your hair already has darkish shade molecules within the cortex, and you set one other shade on prime of it… you’re simply smashing extra shade molecules into the cortex.

Colour will raise virgin hair, however not hair that has already been coloured.

Perms / Straighteners 101

Woman getting permanent wave done on her hair.

We will’t speak about hair concept with out bearing on perms.

First off, there are two kinds of perms: acid and alkaline. Alkaline perms are used for normal-to-coarse hair, whereas acid perms are higher for brokencoloured, and/or finer hair varieties.

Acid Perms are much less damaging however require exterior warmth to course of.

How you can do a Perm

Earlier than beginning a perm, the hair ought to all the time be clarified to take away buildup and different issues that present up within the hair (like drugs). Skip on the conditioner, which interferes with the perm resolution.

Towel dry the hair; when damp, the hair needs to be wrapped with perm rods, utilizing sections which might be the identical size and width because the perm rod.

Likewise, the width of the perm rod will dictate how huge the curls shall be.

When all hair has been wrapped into perm rods, perm resolution needs to be utilized to every rod individually. As soon as the hair has been solely saturated, let it course of for the period of time listed on the field (usually round 20 minutes).

Perm options work by breaking down the disulfide bonds in your hair (the proteins that give your hair form).

As soon as the hair has been absolutely processed, the perm resolution needs to be fully rinsed out, and the hair needs to be blotted with a towel till barely damp.

At this level, a neutralizer is utilized to every perm rod; this rebuilds the disulfide bonds within the new form of the perm rod. Let it sit there for five minutes earlier than eradicating the perm rods and rinsing.

Voila! Now you’ve curly hair!


FAQ Icon
What’s hair concept?

Hair concept is mainly the science of doing hair and studying all of the completely different parts wanted to be a profitable hairstylist. This consists of shade concept, anatomy, chemistry, and even the enterprise facet of operating a salon.

Why is it vital to study concept in hairdressing?

It might be unimaginable to be a very good hairstylist with out understanding how issues work. Lots of science goes into hair shade… and even haircuts, curling, and so forththat’s essential to study.

Closing Ideas

Final Thoughts Icon

Hairstylists must study so many various points of hair by way of concept and expertiseBecause of this, there’s much more that goes into hairdressing than one may assume.

Subsequent time you see your stylist, don’t overlook to understand how a lot work they do to maintain you trying your greatest!

Till subsequent time,


Your Flip: Did you study something cool about hair concept? Is there anything I ought to add to this submit? Drop your ideas within the feedback part beneath!

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