Safety & rules · 7 October 2026 · 2 min read
Will straightening ruin my highlights?
Short answer: it doesn’t have to. Highlighted hair can be smoothed or straightenedDOWN, but it needs the right strength, the right order and someone who tells you the risks before anything goes on.
Chelsea is blonde country. Highlights, balayage, a colourist you’ve had for ten years. So the first question I get isn’t “will it work?” It’s “what will it do to my colour?”
What can happen to colour
- Tone can shift. Some smoothingDOWN systems can warm or lift colour that’s already on the hair. A cool blonde can go a touch warmer. You hear it from me before, not after.
- Bleached hair is weaker. Bleach opens the hair up. Chemistry at full strength on bleached lengths can make them break.
- Toner can fade faster in the weeks after a treatment. Worth knowing before a big event.
How to have both
- Tell me everything. Highlights, bleach, toner, previous smoothingDOWN, a box dye three years ago. The history decides the plan.
- Strength to the weakest part. Roots and lengths can need different handling. Bleached ends get the gentle version, or none.
- Order matters. Talk to your colourist about timing. Usually colour and straightening are spaced apart, not done on the same day. Ask them what they prefer; I’ll work with it.
- Test when in doubt. On heavily lightened hair a test is the sensible first step, in person.
Which treatment
- Frizz only: Straightment Semi, back after 1–4 months, the gentlest.
- Less curl, easier blow-dries: Straightment Demi, about 60% of the curl out, roots after 4–8 months.
- Very bleached hair and Straightment PermanentDOWN is often a no. I’d rather lose the booking than your lengths.
Already had a bad experience?
If a previous treatment left your blonde breaking or straw-like, that’s correction work, and it starts with a consultation. Correction →
Getting here
From Sloane Square it’s one stop to Victoria on the District or Circle line, then the Victoria line to Oxford Circus, a minute from Maddox Street. From the far end of the King’s Road, the bus into town does the rest.
Online consultation → · Straightment SemiDOWN → · Book →
For men
Sides that stick out, frizz, flat or thinning hair, grey gone wiry: most of it can be sorted, and nobody will know you’ve had it done. The men’s pages → · Coming in from nearby →
“Zoltan Vargyai is on a one-man mission to eradicate dryness and damage from London’s hairdos.”
Want this done?
In my chair it's called Straightment DemiDOWN.
Matched to your hair, no line, roots after 4–8 months. £199.95–£569.95, by length.
Prices and booking →More from Safety & rules
- Hair Straightening Treatments Explained: Keratin, Brazilian Blow Dry, Japanese, Nanoplasty and Hair Botox (UK Guide)
- Keratin vs Japanese Straightening vs Brazilian Blow Dry: Which One, How Long It Lasts, What It Costs
- Keratin Treatment Ruined My Hair: What's Happened and What Can Be Fixed
Are you a pro? The full technique is on tecSture. For hairdressers →
