Our science

Every batch must prove itself.

Strands of hair held in the grips of a strength-testing instrument
Strength, measured to the break.

We don’t make the hair and hope it performs. Testing is part of how we make it.

Every production batch is tested by an independent laboratory, blind, on samples taken from the production run. If one tested strand fails our specifications, the entire batch is discarded at our expense. It never ships.

That means finding a problem is supposed to be our problem before the hair ever becomes yours.

Quality shouldn’t be left to chance or opinion. The properties that can be measured should be measured against defined standards. So we use independent testing to tell us exactly what we’re making and whether it meets the requirements we set.

We test. We measure. We adjust. We discard what doesn’t pass.Not the strand. The entire batch.

The testing system

Different questions. Different tests.

Before it reaches your chair, the hair answers three questions through ten tests.

Open a question

Close-up of golden blonde Prolonged Hair strands
IThe material01 — 02
  • Human hair
  • Restricted substances

Fiber identity and material safety are confirmed first.

  1. 01Human hairConfirmed human. Not animal. Not synthetic.
  2. 02Restricted substancesScreened against cosmetic safety thresholds.
Close-up of deep brown Prolonged Hair strands
IIThe fiber03 — 06
  • Strength
  • Elongation
  • Stiffness
  • Cuticle

Independent laboratory measurement of mechanical properties, plus scanning electron microscopy of the cuticle.

  1. 03StrengthBreak stress under controlled load. MPa.
  2. 04ElongationExtension before break. %
  3. 05StiffnessResistance to elastic deformation. Young's modulus, MPa.
  4. 06CuticleScanning electron microscopy of cuticle integrity and fiber surface.
The Prolonged Hair color ring, close-up
IIIThe finished product07 — 10
  • Color
  • Weight
  • Length
  • Construction

Finished product is checked in our operation against its specification. If it fails, it does not ship.

  1. 07ColorAgainst the approved shade target.
  2. 08WeightAgainst the product specification.
  3. 09LengthAgainst the finished-length requirement.
  4. 10ConstructionAgainst the attachment requirements for that product.

The last word

No batch ships until Whitney and Jonathan approve it.

Every batch carries a number that ties it to its records.

Whitney SexsmithJonathan Sexsmith

Under the microscope

Same magnification. Different hair.

Two fibers, side by side at 600× magnification. Look closely at the surface.

600×Magnification, both fibers, under a scanning electron microscope.

Electron microscope images of two hair fibers at 600 times magnification. A: a competitor fiber. B: a Prolonged Hair fiber.
PropertyA. CompetitorB. Prolonged Hair
CuticleDepleted or removed.Robust and aligned, even after Level 12 processing.
OriginMixed-source fibers of inconsistent origin.Human hair with donor-consent letters and purchase records on file, serialized by batch.
FinishA heavy silicone gloss that rinses away, leaving fibers dry and dull.Finished through our Pro•Lock™ Process with the cuticle intact. The shine is the fiber’s own, not a coating.
DensitySparse density that collapses in wear.Denser, fuller strands that hold up to daily wear.

Don’t take our word for it. Take the lab’s.

From independent ASTM and ISO testing. Prolonged Hair at Level 12 against a leading competitor at Level 9.

Independent ASTM / ISO studies

Proof first. Marketing second.

These four results show what the strand withstands, how far it stretches, how well it holds its shape and how much less it breaks.

  • Up to4.3×Tensile strength
  • 2.3×Greater elongation
  • 2.9×Higher shape retention
  • 72.6%Less breakage

What it means at the chair

Visible density.

Visibly denser, healthier strands, even after high-lift processing to Level 12.

Proven precision.

Controlled manufacturing, measured by an independent laboratory, so the hair performs the way the records say it does.

Verified integrity.

Measured strength and stretch. Cuticle-intact hair you can bleach, tone and style like your own. Donor-consent letters, purchase records, and batch serialization on file.

Exclusively for licensed stylists

Your reputation is behind every installation. Ours is behind the hair.

By the time a stylist puts her reputation behind our hair, we should already know what we’re putting ours behind.