Zoltan Hair tecSture · Brazilian & Plastia · DOWN Library
Selagem Termica
Selagem termica — thermal sealing — is a Brazilian treatment that closes and seals the hair cuticle with keratin, amino acids and lipids locked in by a flat iron. It delivers mirror gloss, aligned smoothness and one to three months of frizz control without meaningful straightening — the polish-and-protect tier of the plastia family.
Also known asSelagem, selagem capilar, thermal sealing, hair sealing treatment — the gloss-and-alignment workhorse of Brazilian menus.
- Straightening
- 3/10
- alignment, not straightening
- Frizz
- 7/10
- Damage risk
- 3/10
- heat-dependent
- Longevity
- 4/10
- one to three months
- Upkeep
- 3/10
Origin and chemistry
As Brazil's smoothingDOWN menus stratified, a gap opened below the progressiva: clients wanting the finish — that liquid, sealed, espelhado shine — without the commitment or the chemistry conversation. Selagem filled it: cationic conditioning agents, hydrolysed keratin, amino acids and lipids deposited along the fibre, the iron pass melting and sealing them into a smooth, light-reflecting surface with the cuticle flattened shut. No bond-breaking, no structural change — surface engineering, honestly named. Occasional selagem products add smoothing acids for extra effect; the label, as ever, is the treatment.
Who it is for — and safety
Best for: dull, frizz-prone, porous or colour-treated hair wanting gloss and behaviour; the between-treatments maintenance slot; event hair that must photograph liquid. Not for: any straighteningDOWN expectation. Pregnancy: honest sealing formulas are the calm end of this guide — verify the exact bottle as always. All sensible ages.
In the chair
Clarifying wash, sealing treatment section by section, brief processing, blow-dry, fine-section moderate iron pass — the sealing moment — light finish. Sixty to ninety minutes: the express appointment of the family.
Results, care and climate
Immediate mirror gloss, silk-flat cuticles, frizz politely dismissed, colour looking freshly done; waves aligned, not removed. One to three months depending on wash frequency, fading evenly — endlessly repeatable, the classic six-to-eight-week ritual. Care: sulfate-free washing (the lifespan is measured in washes), weekly gloss mask, heat protection. Hard water is the sealing's nemesis: monthly chelating wash, non-negotiable in London. Rinse and mask around pools; pool-heavy weeks halve it.
What can go wrong
Very little at honest strength: heaviness on fine hair from over-application, fleeting results when sold as more than sealing, heat carelessness on fragile hair. The disappointment reviews all share one cause — someone was promised a progressiva and given a polish.
Compared to
Progressiva — the smoothingDOWN big sister this treatment deliberately is not. Plastica dos fios — reconstruction depth versus this page's surface polish. Hair lamination — the Russian-born parallel on the same gloss shelf. Keratin — the committed coating with real humidity armour.
Questions
What is the difference between selagem and progressiva?
Intent. The progressiva smooths and loosens curl for months via active smoothingDOWN chemistry; selagem seals and glosses the surface with no structural ambition — waves aligned, not defeated. One changes behaviour; the other perfects appearance. Menus price them apart because they are apart.
How long does selagem termica last?
One to three months, counted honestly in washes: sulfate-free care, cooler water and a weekly gloss mask reach the top end; daily washing, hard water and pools reach the bottom. It fades evenly and repeats endlessly — most devotees rebook every six to eight weeks.
Does it straighten or relax curls?
It aligns — curls and waves emerge organised, defined and glossy, their pattern intact. Clients often perceive relaxation because chaos left, not because structure changed. For genuine relaxation or straightening, every stronger tier in this guide awaits.
Selagem or hair botox — which do I need?
Surface versus fill: selagem perfects the outside — gloss, alignment, seal; botox plumps the inside — repair, softness, weight. Dull-but-healthy hair wants selagem; damaged hair wants botox; plenty of hair, honestly, benefits from alternating both.