The Ultimate Guide to Laser Hair Removal

Laser hair removal has been commercially available since the mid 1990’s. Its efficacy is now generally accepted, and its popularity is growing steadily.

According to the American Society for Aesthetic Plastic Surgery, laser hair removal was the third most popular non-surgical aesthetic procedure carried out in 2012 (with the number of treatments exceeding 1.2 million).

What is Laser Hair Removal?

Laser hair removal is the removal of unwanted hair by the process of selective photothermalysis. That is to say that the area being treated is exposed to pulses of laser light with the aim of destroying the hair follicle, causing the hair to fall out.

Laser Hair Removal Regulation

The FDA, which is the US Federation for Drug Administration is responsible for the protection of public health. The FDA’s Center for Devices and Radiological Health regulates laser equipment, whilst the practice of professional hair removal generally is regulated by state and local authorities.

Therefore, providing a laser device is FDA registered and approved for commercial use, you can be sure that it has been rigorously tested for safety.

Conversely, regulation surrounding the qualifications of the operator of this equipment is less stringent, and varies from state to state.

How Laser Hair Removal Works

Laser hair removal devices use visible and invisible (infrared) light to target the dark pigment, melanin, found in hair and skin.

Melanin, which is prevalent around the base of the hair follicle, absorbs the light which is converted to hot energy.  This, in turn, damages the follicle sufficiently to cause the hair to fall out, usually 1 - 2 weeks following treatment.

The process matches a specific wavelength of light and pulse duration, determined by the skin and hair type of each individual. The ultimate goal is to try to cause sufficient damage to prevent regrowth.

Hair removal lasers operate between 700 - 1400 nanometers (nms) depending on which type of laser is being used. (A nanometer is the unit of measurement for the wavelengths of light and infrared radiation).

How Long to see Results?

There is no single definitive answer to this question as it depends upon a number of variables, including the skin and hair type of the individual,  the part of the body being treated, how large the area is, how well the area responds at each session and the type of laser used. 

It is fair to say that laser hair removal, in any case, is not a one-off treatment and multiple sessions will be required, probably between 6 – 8 at intervals of several weeks.

The hair in the treated area will fall out 1 - 2 weeks following the treatment.  Results should become more noticeable after​ about the 3rd session, and progressively after each following session.

Why Multiple Sessions?

To fully understand why many sessions of treatment are required, it is necessary to first have a basic understanding of the structure of the hair follicle and the growth cycle of hair.

Structure of the hair follicle

The hair follicle is the skin organ which produces hairs.

The papilla is a large structure located at the base of the follicle, which is mainly made up of connective tissue.

The matrix, which surrounds the papilla consists of dividing cells, including melanocytes which are the cells which produce melanin, a dark pigment responsible for the colour in skin and hair.

It is cell division in the matrix that form the major structures of the hair fibre.

Growth Cycle of Hair

The hair growth cycle consists of three stages: the growth stage (known as Anagen), the end of growth stage (known as Catagen) and the resting stage (known as Telogen).

During the active growing stage, the cells in the matrix divide to produce new hair fibres and the follicle buries itself into the dermal layer of the skin to provide nourishment for the strand. This is followed by the Catagen stage.

During the Catagen, transitional stage, the follicle shrinks and the papilla detaches, cutting the hair strand off from its blood supply. As the follicle shrinks it pushes the hair upwards.

During the resting stage the follicle remains dormant. At some point, the follicle will begin to grow again, the hair base will break free from the root and the hair will be shed.

The length of the growth cycle depends on which part of the body it inhabits. It is genetically determined and so varies from person to person.

The table below gives an indication based on averages only.

Body Part



Cycle Duration


3 months

1-2 weeks

10 months


3 months

1-2 weeks

10 months


10 weeks

2-3 weeks

14 months

Upper Lip

6 weeks

2-3 weeks

5 months


3 weeks

2-3 weeks

5 months


3 months

2-3 weeks

8 months


16 weeks

2-3 weeks

10 months


24 weeks

3-6 weeks

11-12 months

Significance to Laser Hair Removal

All hair is not in the same growing stage at the same time, so when an area is treated only a percentage of the hair follicles will be affected.

Close up of hair growth

Therefore, it is necessary to re-treat the area several times to make sure all the follicles are caught at the correct time.

Is Laser Hair Removal Permanent?

The FDA has recognised and approved certain devices as providing permanent hair reduction.

Their definition of this is:  "the long​ term, stable reduction in the number of hairs re-growing after a treatment regime, which may include several sessions.  

Man having laser hair removal on back

Permanent hair reduction does not necessarily imply the elimination of all hairs in the treatment area."

What Does Permanent Hair Reduction Mean?

​The FDA further states that the number of hairs re-growing must be stable over time greater than the duration of the complete growth cycle of hair follicles.

As can be seen from the table above, this can vary from 4 - 12 months depending on body location.  So in terms of the FDA definition, "permanent" can vary.

​Good results can be achieved,  of up to 80% reduction or more.  It is most likely that, following initial treatment regime, top-up maintenance sessions will be required at least annually.

Is Success Guaranteed?​

​According to the American Society for Dermatologic Surgery it is impossible to determine in advance who will require how many treatments and how long hair will remain gone.

​In fact, success generally is impossible to determine in advance.  Inexplicably, some individuals who are seemingly "ideal" candidates i.e. with light skin and dark hair, will not respond well to the treatment.

Conversely, some have reported complete hair removal (this is not necessarily common and should not be expected).​

It is true to say, however, that good results have been achieved in the majority of cases and that many individuals have expressed themselves very happy with the outcome of their treatment.

Laser Hair Removal - Limitations

3 women with different hair and skin types

​Whilst certain lasers for hair removal are now able to successfully treat darker skin, there are still none suitable for fair, grey or light red hair.

Although it is likely that this will be remedied at some time, in the not too distant future, the only permanent solution in these cases currently available is electrolysis.

What are the Different Types of Laser?

With the popularity of laser hair removal steadily increasing all the time it is no surprise that the technology is advancing in leaps and bounds.

There are many different devices currently in use, utilising various laser systems, namely Ruby, Alexandrite, Diode and Nd:YAG.

​The following gives a brief summary of each type of laser, their relative merits and disadvantages and for which skin tone on the Fitzpatrick scale (shown below) each can be used.

The Fitzpatrick Scale

The Fitzpatrick scale was developed in 1975 to classify complexions and their tolerance to sunlight.  It is widely used as an aid to determining which laser hair removal treatment is most suitable for each individual.

Skin Type

Skin Colour

Hair Color (darkest)

Eye Colour



White or very pale


Blue, grey, green

Always burns, never tans


Pale white with beige tint

Chestnut or dark blond


Always burns, sometimes tans


Beige to light brown (olive)

Dark brown

Dark brown

Sometimes burns, always tans


Light to moderate brown



Rarely Burns, always tans


Medium to Dark Brown


Brownish black

Rarely burns, tans more than average


Dark brown to black



Never burns

The Ruby Laser

The Ruby Laser (epilaser) was the first to be developed for use commercially as a laser hair removal system.  It has a proven track record for both efficacy and safety.

It works best for those with light skin and dark hair, and has an inbuilt cooling system which conducts heat away from the skin before, during and after each pulse of the laser.

There is a 2 second delay between each laser pulse in order to take the heat from the skin, thus reducing the risks of burns.  This also reduces the pain - the quicker the laser pulse, the more discomfort is felt.



Which Skin Type?

Skin types I and II on the Fitzpatrick scale.

Pros of Ruby Laser

  • Long term hair reduction can be achieved.
  • Less painful than other laser hair removal systems
  • Hair regrowth is often finer and sparser
  • Built in  cooling equipment minimizes risk of burns and other side effects

Cons of Ruby Laser

  • Not suitable for tanned or dark skin
  • Relatively small treatment area
  • slow laser repetition rate means longer treatment times
  • some risk of burns, scars, redness, swelling, and skin discoloration
  • Technology has become somewhat outdated as newer, more sophisticated systems have been developed


The Ruby laser has a long track record of achieving good results in hair reduction for those with dark hair and fair skin.

There are other, newer types of laser devices which have been developed to treat individuals which fall outside of these parameters.

The Alexandrite Laser

The Alexandrite laser uses an alexandrite crystal as the laser medium, emitting red, near infrared light.

This laser has a relatively large spot size and so is considered to be the fastest of the lasers.  It has the ability to treat large areas, e.g. back and chest very quickly.

It is most effective for light - olive skin tones and dark hair.​



Which Skin Type?

Skin types I - III on the Fitzpatrick Scale

Pros of Alexandrite  Laser

  • Rapid laser repetition means short treatment times
  • Effective on skin types from white to olive tones
  • Can effectively treat thinner hair types than other lasers
  • Covers large areas of skin, with excellent penetration rate

Cons of Alexandrite Laser

  • Not suitable for tanned or dark skin
  • Can cause changes to your skins pigment
  • Can be more painful due to high repitition rate


​The Alexandrite laser hair removal system is ideal for treating large areas and is best suited to those at the lower end of the Fitzpatrick scale, who have dark hair.

The Diode Laser

These machines are relatively new and are different to other systems in that diodes or semiconductors  are used to form the light source of the laser..

The laser wavelength can be adjusted to suit your needs by changing the current applied to the diodes.

Diode laser hair removal systems are suitable for use on darker skin types and best for thick, coarse hair, making them ideal for treating back and chest areas.


800nm - 810nm​

Which Skin Type?

Skin types  I - IV on the Fitzpatrick Scale

Pros of Diode Laser

  • Longer wavelength allows deeper skin penetration
  • Large areas of skin can be treated
  • Fast recovery
  •  Adjustable laser wavelength - flexibility
  • Can effectively treat  darker skin types
  • Reduced risk of epidermis damage

Cons of Diode Laser

  • Side effects may include burns and skin discolouration
  • Have been linked to urticaria (hives)
  • Limited research available on long term results


Diode laser systems effectively treat large areas, quickly.

They are suitable for all skin types, but particularly for I - IV on the Fitzpatrick scale.

There is limited research available on which to form conclusions as to long term efficacy and safety as they are the newest of the laser hair removal systems currently available.​

​Nd: YAG

Nd:YAG (Neodymium-doped Yttrium Aluminum Garnet) laser hair removal systems were developed specifically to be effective on all skin tones, including Asian, for which other systems are ineffective and can be unsafe.

It operates at a higher frequency than other lasers and can therefore penetrate the skin more deeply.  It can also operate at a lower frequency, emitting green light to penetrate hair follicles closer to the skin's surface.

It has a large spot size and fast repetition rate, making it suitable and effective for larger areas of skin such as the back, chest and legs.


​1064nm  / 532nm

Which Skin Type?

Skin types I - VI (all) on the Fitzpatrick Scale

Pros of Nd:YAG

  • This system can work on all skin types including asian and dark skin tones
  • Large areas of the skin can be treated quickly and efficiently
  • There may be a  longer delay in hair regrowth than with other laser hair removal systems
  • Currently offers the most advanced technology on the market 

Cons of Nd:YAG

  • Can be painful
  • Less effective clearance of fine, lighter hair
  • Limited research available on long term results


​Nd:YAG Laser hair removal systems provide the newest most advanced technology currently on the market.  They are suitable for all skin types, but most effective for darker skin and coarse dark hair.

​Can treat large areas quickly and effectively, but can be more painful than other systems.

What About IPL​?

Stricly speaking, IPL (intense pulsed light) is not a laser system, the main difference being the way in which light is used.  In order to avoid confusion, we have included a brief outline below,  as some clinics still offer IPL hair removal.

Whereas lasers emit light rays of a single wavelength (monochromatic), IPL  uses full spectrum light (polychromatic) and low-range infrared radiation.

The rays are filtered to allow range of wavelengths (between 500 – 1200 nm’s).  This means that IPL uses a scattered approach, covering a larger area than lasers, but in a less targeted way.

 For more a more in-depth comparison see here


Variable 500 - 1200nm​

​Which Skin Type?

Skin type I - II on the Fitzpatrick Scale​

Pros of IPL

  • Can treat large areas
  • May be less painful than laser treatment
  • Cheaper alternative to laser

Cons of IPL

  • Only effective for light skin
  • Generally considered to be less effective than laser hair removal
  • Outdated technology


IPL is most suited to treating individuals with light skin and dark, coarse hair, but the technology is rather outdated and generally considered less effective than laser hair removal.

Potential Side Effects of Laser Hair Removal

Laser hair removal, as with all surgical procedures, involves a certain level of risk and potential side effects.

Some of these are transient and more or less to be expected whereas​ for other, more serious side effects precautions need to be taken to minimise the risk.

"Normal" Side Effects

Itching, redness and swelling following treatment are very common and only temporary.

This is a more severe example of a rash from laser hair removal

These should be fully explained at the initial consultation prior to  treatment , together with advice as to what you can do to alleviate them.

Patch tests i.e. laser treatment carried out on a small, unobtrusive area several days prior to treatment will minimise potential risks, enable the clinician to ensure that the laser is set correctly for your hair and skin type and act as a gauge to likely effectiveness.

Less Common Side Effects​

Some of the potentially more serious but less common side effects are:

  • Allergic reactions – numbing creams are sometimes used to minimise pain, which could cause an allergic reaction, however the patch test should detect this prior to treatment of a larger area
  • Burns – these are not usually severe, if equipment is properly used, and are transient and comparative to minor sunburn.
  • Hyperpigmentation – It is possible that your skin may react to the laser light by producing additional pigment cells and causing patches of darker skin (particularly in individuals with light skin)
  • Hypopigmentation –  If the laser is set incorrectly it will also attack the pigment in the skin of the treatment area, causing lighter patches (particularly in individuals with darker skin).
  • Scabs –  Laser light can cause scabbing to occur – usually fairly minor, similar to those produced by tattooing.
  • Infections – Incorrectly used lasers can easily cause damage to the skin which is then prone to infections.  These have the potential to become serious.
  • Bruising – Bruises can occur as a result of damage to the small blood vessels near the surface of the skin.
  • Changes in Sensation – occurs if the nerve endings are damaged, resulting in tingling or numbness.
  • Increased Hair Growth – a rarity for which there is no current understanding of the cause.

Precautions to Minimize Risks

Before Treatment​

Before embarking on any laser hair removal treatment you should carry out the following precautionary measures to minimize any potential risks:

  • Check that the laser device to be used is FDA approved for hair removal
  • Carry out research to check that the clinician is medically trained, fully qualified and experienced for the equipment being used
  • Consult with your dermatologist - they can advise you as to whether your skin is suitable for  laser hair removal as well as explaining what you can expect during the treatment programme and the associated risks and benefits
  • If you are taking any medication, consult your doctor - some medications cause the skin to become more sensitive
  • Avoid exposure to the sun for as long as possible, and at least 4 weeks prior to treatment
  • You should avoid artificial tanning products and lotions
  • Plucking, waxing or any other type of hair removal involving pulling hair out by the root should be avoided (shaving is, however, fine and can even increase the effectiveness of the treatment)
  • For underarm hair removal, use of deodorant should be avoided for couple of days prior to treatment
  • Moisturizing lotion or other creams should be avoided for 24 hours before each session

After Treatment

  • For any minor irritations e.g. itching, redness and swelling, a soothing lotion can be used.  This should be very temporary - if it persists take advice from your dermatologist
  • Gently exfoliate the treated area with a loofah sponge or washcloth to shed dead hair cells two or three times per week
  • Treat any regrowth by shaving, do not remove hair from the roots (by plucking or waxing etc. in between sessions
  • Avoid sunlight as much as possible, and use sunscreen liberally if you are going to be exposed to sunlight for long.  (Your skin will be more sensitive and prone to sunburn)

How painful is Laser hair Removal?

​Most individuals find the pain from laser hair removal to be tolerable.  It has been compared to having an elastic band pinged against the skin.

However, some people have more sensitive skin than others and some a lower threshold for pain.

How to Reduce the Pain

  • Having a patch test prior to treatment will give an idea of what to expect.
  • Sometimes a numbing cream can be used, or painkillers taken prior to treatment.
  • Discuss the options with the physician at the time of the patch test.​

Cost of Laser Hair Removal

The overall cost of any hair removal treatment programme will obviously vary depending upon a number of factors.

The cost of each individual session can range from $150 - $250 for underarm and from $600 - $1,100 for full arms/legs

Given that full treatment is likely ​to consist of up to 8 sessions, it is easy to see that a significant outlay will required.

It is important to "shop around" before making a choice, but we would advise against making the choice purely based on cost alone. We would also advise a cautious approach to cut price deals.

Is Laser Hair Removal Safe?

​Laser hair removal is inherently safe, provided it is carried out by a suitably trained, qualified and experienced practitioner in a safe and controlled environment.

Non Physician Operators are responsible for a high rate or laser hair removal injuries due to treatment errors

A recent clinical survey entitled “Treatment Errors resulting from use of lasers and IPL by medical laypersons: results of a nationwide survey”  concluded that laser hair removal should not be carried out by insufficiently trained, non-medical operators with inadequate diagnostic abilities.

In addition, that their lack of knowledge often led them to make unrealistic promises to the consumer.

What about Radiation from Laser Hair Removal?

It is ionizing electromagnetic radiation which is associated with ​burns, radiation sickness, genetic damage and cancer.

​The type of radiation used in laser hair removal systems is non-ionizing electromagnetic radiation and therefore does not pose a serious health risk.

​Further Information

For more in-depth information regarding the safety of laser hair removal see our articles:


For the past 12 months, I have been testing and playing with all sorts of hair removal products for Hair Free Life. My goal is to provide the most accurate and up-to-date hair removal consumer information on the internet. When I'm not photographing, reviewing and researching hair removal products I play the drums in a samba band and am a volunteer for the Swindon Lions! Got any questions? Write to us below: