For anyone trying to grow their hair out or hold onto length they already have, especially if breakage along the strand, not just split ends, is the issue. Redken markets it across hair types and textures, and it's safe for color-treated hair. It's best used as part of the full Extreme Length system (shampoo, conditioner, leave-in) rather than as a standalone swap-in for a regular conditioner, since the breakage-reduction and growth figures Redken publishes are based on using all three products together.

The real hook of this conditioner is the mechanism, not just the ingredient names: hair usually stops looking longer not because it stops growing but because the ends keep breaking off, and this formula is built specifically to reduce that breakage along the strand using biotin, castor oil, and Redken's Length Care Complex. That's a meaningfully different job than a conditioner focused on shine or softness, which is why Redken sells it as part of a three-product system rather than a single stand-alone bottle — the conditioner's contribution is protecting length day to day between the shampoo and leave-in steps.

After shampooing with Extreme Length Shampoo, apply the conditioner to damp hair and distribute through the lengths and ends. Rinse thoroughly, then follow with Extreme Length Leave-In Treatment With Biotin for the full system. If it gets in eyes, rinse immediately.

Pros: biotin and castor oil paired with Redken's own Length Care Complex give it a specific, stated mechanism (reducing strand breakage) rather than a vague 'healthy hair' claim; it's a vegan, silicone-free formula also positioned as safe for color-treated hair; suitable across a wide range of hair types and textures. Cons: the standout stats, 81% less breakage and up to 6 inches of growth in a year, are system-wide results from using the shampoo, conditioner, and leave-in together, so using this conditioner alone likely won't reproduce those figures; it contains mineral oil and several fragrance-related compounds (limonene, linalool, benzyl benzoate) that can matter to shoppers avoiding either ingredient; it doesn't make hair grow faster on its own — it works by limiting breakage of hair that's already growing.