How to Choose the Right Professional Keratin Treatment

Choosing a professional keratin treatment should never begin with one question: “Which formula is the strongest?”

The strongest formula is not automatically the right formula for every client. A treatment that performs beautifully on dense, resistant curls can overload fine hair, while a highly nourishing formula developed for sensitized blonde hair might not provide enough control for coarse, tight curls.

Professional keratin selection must begin with a complete hair diagnosis.

At Queen’s Hair Academy, treatments are compared by hair thickness, curl pattern, hair history, damage level and porosity. Straightening strength, nourishment and film density are then evaluated together to find the most appropriate professional formula.

Why One Keratin Formula Cannot Work for Every Client

Two clients can have a similar curl pattern but require completely different treatments.

One client may have natural, coarse and resistant hair. Another may have fine, highlighted and highly porous hair. Both may want a straight result, but their hair cannot safely tolerate the same formula, heat level or number of flat-iron passes.

A professional diagnosis should always consider the complete hair profile—not one characteristic in isolation.

Step 1: Identify the Hair Thickness

Hair thickness affects how much straightening strength, nourishment and film density the fibre can tolerate.

Fine Hair

Fine hair can be easily overloaded by a heavy formula or dense protective film.

The selected treatment should provide enough smoothing strength without unnecessarily flattening the hair or removing its natural movement. Heat must be controlled carefully, particularly when the hair is blonde, highlighted or sensitized.

Medium-Thickness Hair

Medium-thickness hair can work with a broader range of professional keratin treatments.

The final choice should be refined according to the curl pattern, porosity, chemical history and damage level. Medium-thickness hair with light waves will not require the same treatment profile as medium-thickness hair with strong curls.

Coarse and Resistant Hair

Coarse and resistant hair generally requires stronger curl control and a heavier protective film.

However, coarse hair is not automatically healthy hair. Previous colouring, lightening, dryness, porosity and elasticity must still be evaluated before selecting a powerful formula or an intensive heat protocol.

Step 2: Assess the Curl Pattern

The curl pattern helps determine the amount of straightening strength required.

The Queen’s Hair Academy Keratin Selection Guide uses four profiles:

• Light waves
• Medium waves
• Curly hair
• Tight curls

Light waves may need frizz control and smoothing rather than maximum straightening. Curly and tight-curled hair generally requires greater alignment and discipline.

Curl pattern must never be evaluated alone. Fine hair can have strong curls, and coarse hair can have only a light wave. These profiles require very different professional decisions.

Step 3: Review the Hair History

Before selecting a treatment, determine whether the hair is:

• Natural
• Colour-treated
• Highlighted
• Blonde or bleached
• Previously straightened
• Chemically processed
• Dry, brittle or damaged

Natural hair does not always mean low-porosity or healthy hair. Colour-treated hair does not always mean severely damaged hair. The current elasticity, porosity and condition of the fibre must be assessed separately.

Blonde and highlighted hair require additional caution because lightening can affect porosity, elasticity and heat tolerance.

For professional safety screening, the Queen’s Hair Academy selection system disables Damage Levels 1–2 and low porosity when Blonde Hair or Highlighted Hair is selected. The professional must then choose between Levels 3–5 and medium-to-high porosity.

Step 4: Determine the Damage Level

Queen’s Hair Academy uses a five-level professional damage system.

Damage Levels 1–3

Hair within Levels 1–3 is generally suitable for keratin treatment when the formula and protocol are correctly matched to the complete hair profile.

The professional must still adjust the treatment according to thickness, porosity, curl pattern and chemical history.

Damage Level 4

Level 4 hair requires:

• A highly nourishing professional formula
• An individually adjusted heat protocol
• Careful control of the number of passes
• A mandatory strand test

Not every keratin treatment is suitable for Level 4 damage. If the hair does not tolerate the sealing process, a restorative treatment should be selected instead.

Damage Level 5

Keratin treatment is not suitable for Level 5 hair damage.

At this stage, the priority should be professional Cold Recovery or Hair Repair & Smoothing treatments. The condition of the fibre must be improved before a straightening service can be considered.

Step 5: Evaluate the Porosity

Porosity describes how the hair receives and retains moisture and treatment products.

Low Porosity

Low-porosity hair has a compact cuticle and can resist product penetration. A heavy or excessively nourishing formula may create unnecessary buildup and weight.

Medium Porosity

Medium-porosity hair generally responds more predictably and can tolerate a wider range of professional treatments. Thickness, curl and hair history must still guide the final decision.

High Porosity

High-porosity hair may absorb and lose moisture unevenly. It often requires greater nourishment, structural support and careful heat control.

High porosity does not automatically mean that the heaviest formula should be selected. The strand test must confirm how the fibre responds.

Straightening Strength, Nourishment and Film Density

These three characteristics work together, but they are not the same.

Straightening Strength

Straightening strength shows how strongly the formula can relax or straighten the curl.

A 5/5 treatment is not automatically suitable for every client who wants straight hair. The hair structure must be able to tolerate both the formula and the required sealing protocol.

Nourishment

Nourishment reflects how much support the formula provides to dry, porous or chemically sensitized hair.

Blonde and highly porous hair generally require greater nourishment than healthy natural hair.

Film Density

Film density describes the weight and protective coating created around the hair fibre.

• Light film: smoothing with minimal weight
• Medium film: balanced control and discipline
• Heavy film: greater weight and curl control for dense or resistant structures

A strong keratin can have moderate nourishment. A highly nourishing keratin can have a lighter straightening effect. These values must therefore be compared separately.

Secondary Performance Characteristics

After the primary diagnosis, the professional can compare:

• Shine
• Heat protection
• Odour intensity
• Longevity
• Processing time
• Desired straightening effect

These characteristics help refine the final choice, but they should never replace the structural diagnosis.

Why the Strand Test Is Mandatory

A strand test helps confirm:

• Heat tolerance
• Elasticity
• Colour response
• Straightening performance
• Required number of passes
• Whether the formula creates too much or too little weight
• Whether the hair can safely tolerate the full service

There is no single universal temperature or number of passes for every keratin treatment.

The professional must follow the product-specific Heat Guide, the manufacturer’s protocol and the response of the tested strand.

The Correct Selection Order

For a consistent professional consultation, follow this order:

1. Identify hair thickness
2. Assess the curl pattern
3. Review the hair history
4. Determine the damage level
5. Evaluate porosity
6. Confirm the desired result
7. Compare straightening strength, nourishment and film density
8. Perform a strand test
9. Select the individual heat and application protocol

No single characteristic should determine the entire service.