The hair guide

What “Remy” really means

Human hair is not all the same. Remy (or Remi) usually indicates that the cuticle layer is largely intact and aligned in one direction, root to tip — similar to how hair grows. That alignment matters for shine, reduced tangling when the hair is handled correctly, and a more natural drape and blend with your own hair.

Non-Remy or mixed-pile hair is often more aggressively processed, which can make it feel drier or tangle more quickly. When you read product copy, look for transparent sourcing and, once you trade, for claims you can back with supplier documentation. This guide stays educational; your legal and buying teams should align every live claim with the batch you actually sell.

Length, weight, and method

Length is measured in inches or centimetres when the hair is straight. Wavy and curly extensions look shorter at the same “raw” length — if you wear your hair in its natural texture, allow for that when you order.

Weight (grams per pack or weft) controls fullness. Too little hair can look thin at the ends; too much, especially for fine bio hair, can feel heavy. If you are new to extensions, a modest weight with a pro colour match often looks more believable than maximum density on day one.

Method (weft, tape, micro-ring, clip-in, etc.) changes install time, how often you move the hair up, and how you wash around bonds. SUNDAY will spell out the method per SKU when the catalogue is live — use those PDP instructions over any generic web advice.

Colour and undertone

Match to the mid-lengths and ends you want the extensions to sit with, not always to the root, especially if you colour or sun-lighten. Natural light reveals undertone: ash, gold, or neutral. Screens distort colour, so in production many brands offer swatch rings or sample wefts before a full set — a useful upsell and a way to cut returns.

Balayage and rooted shades exist to make blends forgiving; if in doubt, slightly too neutral is often easier to adjust with toning in-salon than a shade that is too warm or too flat.

First wear and brushing

Before heat or styling, detangle from the ends upward with a wide-tooth comb or a brush designed for extensions. Tugging from the top down stresses bonds and the cuticle. If you use clips or bands, place them where they do not snag the attachment points.

When you add heat, use a heat protectant and stay within the temperature range your product’s label allows — “heat safe” still has limits.

Wash day routine

Wash less often than you might your scalp-only routine: overwashing accelerates wear on the hair and can loosen some install types. When you do wash, keep the water warm (not scorching), work shampoo gently along the hair without rough circles at the root line, and condition from mid-lengths down — keep heavy conditioners off tape or bond areas if your install type says to.

Pat dry with a microfibre towel; do not rub. Detangle again while the hair is damp and use a detangling or leave-in product suited to human hair, such as a lightweight spray that supports slip without build-up — like the SUNDAY line direction on the homepage haircare block (final formulas TBC at launch).

Between wears

Store clip-ins and removable pieces in a breathable bag or box, brushed smooth and completely dry, away from direct sun and bathroom steam when possible. For longer storage, a loose braid can reduce tangles. Never put extensions away damp — that invites odour and fibre damage.

Lifespan and when to replace

Even excellent Remy hair is not forever. Friction, heat, hard water, and colour work all shorten life. A common range for well-cared human-hair pieces is on the order of months to a year or more of regular wear depending on method, density, and routine — your warranty and PDP copy should state what you stand behind for each product.

Replace when the ends stay dry or feathery after conditioning, when shedding or tangling jumps suddenly, or when the colour no longer matches after your own hair has shifted.