How to Analyze Your Client's Hair

Hair analysis is an important element of client consultation helping you to determine the condition of the hair and scalp.


Always explain any procedure before starting a treatment; if there is any doubt about the end result, the client must be informed. It is recommended that a diagnostic record card be used to record all aspects of a consultation. It may be appropriate to ask the client to sign a document, stating they are in agreement with the suggested course of action and are aware of any reservations you may have.


The senses of sight, smell and touch provide a wealth of information to the skilled stylist. However, further direct testing is required to confirm the condition of the cortex, the porosity of hair, any allergic sensitivity to a product, and the presence of chemicals from previous treatments.


Porosity Test
Porosity is a measure of the hair’s capacity to absorb moisture. Damaged hair (usually negatively charged) will be highly porous, with an open cuticle layer exposing the inner cortex. Hair in this condition will look dull and dry, and may be prone to breaking. The more porous hair is, the faster a treatment will take effect, and processing times should be adjusted accordingly.


Ideally, damaged, very porous hair needs to be cut out before coloring or perming goes ahead. Sometimes porosity will vary; this is particularly common in long hair, with oily roots and dry ends.


With one hand, select an individual hair or group of hairs at the tip of the shaft. With the other hand, slide thumb and first finger down the hair shaft(s) from the tip to the base. Assess how rough or smooth the hair is, using the following guidelines to determine a course of action:


Smooth and glassy
The cuticle is dense and hard. Hair with poor porosity may lack moisture and will be resilient to treatment.


Slightly rough
This usually indicates healthy, normal hair.


Too porous: hair may have been treated previously. Use a pre-conditioning product.


Very rough, brittle and dry
Indicates damaged hair, which may be the result of over processing. Use a repair treatment or cut out the damaged parts.


Diameter Test
Fine hair will normally be more prone to excessive oil or overloading; conversely, thick hair may take longer to react to a treatment. Assessing the diameter of hair will provide useful information when deciding on a repair treatment or adding color or curl.


With experience, feeling the hair is often all that is required, however a calibrator will accurately test hair diameter. Place an individual hair between the gauges and read the scale to determine hair type. It is worth noting that hair is often oval, or slightly flattened in profile, and so several readings should be taken in order to analyze the diameter correctly.


Elasticity Test
The elasticity of hair can determine the condition of the cortex; well-conditioned hair is springy and bouncy. In order to test for elasticity, take a single strand of hair between both thumbs and forefingers and stretch the hair (it may be necessary to detach a hair from the client’s head).


Healthy hair will stretch roughly an extra 1/3 its length and return to original size. Damaged hair may not return fully to original size, whilst dry or brittle hair may break when put under tension. Use the results from this test to determine whether additional care is required prior to any treatment or style.


Allergy Alert Test (AAT)
In rare cases an allergic reaction can produce redness, itching and blistering. Therefore an allergy alert test or another evaluation should be performed, before each product use, even by clients who have already used coloring products before. Remember that the allergy alert test has to be performed 48h before use. Your client should perform the allergy alert test on an area of skin sized approximately 1cm x 1cm on the inside of the elbow.

  • Apply a small amount (app. size of a pea) of the Color Cream in a thin layer on the inside of the elbow with a cotton bud
  • Leave it uncovered for 45 minutes
  • After 45 minutes, wash off the Color Cream carefully with lukewarm water

If any reaction occurs during the processing time or during the following 48 hours, your client should rinse immediately and a coloration should not be performed.

This test represents an important precaution. However, be aware that even if an allergy alert test has been carried out the client may still experience an allergic reaction when coloring the hair. The allergy alert test is not a guarantee of avoiding future allergic reactions. Please ask your client to consult a doctor if there are any doubts.


Incompatibility Test / Metallic Salts Test
Some products that a client may have used on their hair can react badly to chemicals used within the salon. These typically include hair color restorers, which leave behind a chemical residue of metallic salts that can cause hair to turn green, steam or break off when combined with hydrogen peroxide or similar.


Often a client will forget or fail to mention the use of a product, and in the context of hair restorers the terminology implies that hair is truly restored to its original color; this is obviously not the case!


If the previous use of a chemically based product is suspected, or there is a possibility that a previous treatment hasn’t been removed, use the following test:

  • Mix 40ml of 20 volume (6%) hydrogen peroxide with 2ml of ammonia
  • Cut a few hair samples from the client’s head (make sure this is from the suspected area) and hold them together with cotton or sticky tape
  • Place the hair samples in the solution and leave for up to 30 minutes

If the hair has changed color or bubbles have formed, or if the solution is warm, do not proceed with any hairdressing process that contains hydrogen peroxide.