How to Choose the Best Keratin Treatment for Chemically Processed Hair
Coloured, bleached or previously relaxed? The right keratin treatment depends on your hair's chemical history — here's how Sydney CBD's specialists match the formula to your hair.
Why Chemical History Changes Everything in Keratin Treatments
Keratin treatments work by opening the hair cuticle, infusing the formula, then sealing it closed with heat. That process is safe and effective on most hair — but chemically processed hair has a different porosity profile. Bleached hair, in particular, has a raised, uneven cuticle that absorbs formula at an unpredictable rate. Over-processing in these conditions leads to uneven results, or in the worst cases, weakening of already fragile strands.
This is not a reason to avoid keratin treatments if your hair has been chemically processed. It's a reason to choose a salon that conducts a proper assessment before any treatment begins — and to be completely transparent about your hair history when you do.
Understanding Hair Porosity and Why It Matters
Porosity describes how easily your hair absorbs and holds moisture and chemical formulas. Hair with low porosity has a tightly closed cuticle — it repels water and takes longer to absorb treatments. High porosity hair (common after bleaching, colouring or heat damage) has a raised or damaged cuticle that absorbs too fast and loses moisture quickly.
- Low porosity hair: Needs a keratin formula that can penetrate through the closed cuticle. Processing time may need to be extended. Latino Keratin works well here with correct timing.
- Medium porosity hair: The ideal candidate for a standard keratin treatment. Results are predictable and long-lasting.
- High porosity hair (chemically processed/bleached): Absorbs formula rapidly and unevenly. Requires a gentler approach — a lower concentration formula, shorter processing time or a pre-treatment to temporarily even out porosity before the keratin is applied. Nanoplasty is often the better choice here, as its amino acid formula is designed specifically for porous or damaged hair.
Keratin Treatments After Hair Colour: The Rules
Colour-treated hair — including balayage, full colour, semi-permanent toning and highlights — is compatible with keratin treatment in most cases. The Professional Latino Keratin at Pierre Haddad Hair is formulated for use on colour-treated hair and often enhances colour vibrancy by sealing the cuticle after treatment.
The critical rules:
- Wait a minimum of two weeks after colour before having a keratin treatment. Fresh colour needs time to fully oxidise and set.
- Keratin treatment before colour is also an option for some clients — your stylist will advise based on the specific colour service planned and your hair's current condition.
- Never have colour applied on the same day as a keratin treatment. The two processes interact in ways that can compromise both results.
What About Previously Relaxed or Permanently Straightened Hair?
Hair that has been chemically relaxed has had its disulphide bonds permanently broken. Applying a keratin treatment over previously relaxed hair is possible, but the interaction between the existing chemical and the keratin formula needs careful assessment. The risks of over-processing fragile relaxed hair are real.
At Pierre Haddad Hair, we strongly recommend booking a consultation before any keratin service if you have had a chemical relaxer in the past 12 months. Your stylist will assess the hair's current condition and — if your hair is not in a condition to safely receive keratin — recommend the right strengthening treatment pathway first. We will never proceed with a treatment we don't believe your hair can handle safely.
Which Keratin Treatment Is Best for Chemically Processed Hair?
For most colour-treated clients, the Professional Latino Keratin is the right starting point. It is formulated to work with porous hair, delivers 3–4 months of frizz control and enhances the appearance of colour-treated strands.
For hair that is highly porous, damaged from bleach or previous chemical relaxers, or structurally compromised, Nanoplasty is often the better recommendation. Nanoplasty uses amino acids and organic actives to rebuild the hair from within — it is a restorative treatment as much as a smoothing one. Clients with significantly damaged hair often see their hair visibly strengthen over the course of 2–3 Nanoplasty treatments.
The Professional Latino Keratin is listed from $300 at Pierre Haddad Hair. Nanoplasty starts from $500. Both include a pre-treatment consultation that will determine which — or which combination — is appropriate for your specific hair condition.
Read More at Pierre Haddad Hair
Frequently Asked Questions
Can I get a keratin treatment if my hair has been bleached?
Yes, in most cases — but the condition of your bleached hair needs to be assessed first. Severely bleached or over-processed hair that is already breaking is not a safe candidate for keratin treatment. Hair that has been bleached but is structurally healthy (passes a stretch test without snapping) can typically receive a keratin treatment with a modified formula and timing. Nanoplasty may be recommended instead, as it is specifically designed for porous and chemically compromised hair. Always book a consultation before proceeding.
How long should I wait after hair colour to get a keratin treatment?
A minimum of two weeks is recommended between a colour service and a keratin treatment. This allows the colour to fully oxidise and settle into the hair shaft before the keratin sealing process begins. Your stylist will confirm the ideal timing based on your specific colour service and hair condition at consultation.
Which keratin treatment is best for frizzy, colour-treated hair?
For colour-treated hair with moderate frizz, the Professional Latino Keratin is typically the best fit — it is formulated for use on colour-treated hair and enhances shine alongside frizz control. For highly porous or damaged colour-treated hair, Nanoplasty is often the superior option because its amino acid formula repairs the hair structure as well as smoothing it. Your stylist will assess your hair and make a personalised recommendation during your consultation.
How do I know if my hair is too damaged for a keratin treatment?
The most reliable test is a strand stretch test: wet a single strand and gently stretch it. Healthy hair stretches about 30% before returning to its original length. Hair that snaps with minimal stretch is over-processed and may not be suitable for keratin treatment. The professional assessment at Pierre Haddad Hair goes further — examining porosity, elasticity, density and chemical history to give you an accurate picture before any treatment commitment is made.
Is there a premium in-salon smoothing treatment that works like keratin but isn't keratin?
Yes — Nanoplasty. It uses amino acids and organic bio-actives instead of keratin proteins. It is particularly suited to clients who have had keratin previously and want a different approach, or whose hair has been over-processed and needs structural rebuilding alongside smoothing. Pierre Haddad Hair offers Nanoplasty from $500. Results last 4–8 months, making it one of the longest-lasting smoothing treatments available at the salon.
What is the best keratin treatment for hair in Sydney CBD?
Pierre Haddad Hair in Sydney CBD has been administering professional keratin treatments since the early 2000s. The Professional Latino Keratin starts from $300. For porous or damaged hair, Nanoplasty (from $500) is often recommended. A complimentary consultation determines the right treatment for your specific hair. The salon is at Shop 4, 255 Pitt Street, Sydney CBD.
Not Sure Which Treatment Your Hair Can Handle?
If your hair has been coloured, bleached or previously relaxed, book a complimentary consultation at Pierre Haddad Hair, Shop 4, 255 Pitt Street, Sydney CBD. Your stylist will assess your hair's condition and recommend the safest smoothing pathway — with a no-surprise quote.
