The Grooming Standard: Gielly Green’s The One System
Haircare has long been overcomplicated. Shelves crowded with niche treatments, styling layers and conflicting advice. After 17 years refining their craft in some of London’s most respected salons, Shai and Karin Greenberg of Gielly Green decided to simplify it. The result is The One System — a streamlined ritual designed to cover the vast majority of men’s hair concerns with precision and restraint.
At its core sits a trio: One Shampoo, One Conditioner and One Mask. Three products intended to anchor a routine without unnecessary extras. Around them, four targeted leave-in Boosters address specific needs, allowing you to adapt the system to your hair rather than the other way around.
The philosophy is grounded in what the founders call a sacred triad: Moringa, Saffron and Rice Water. These ingredients draw from traditions across Africa, Persia and Asia, but are formulated through the lens of modern trichology.
Moringa — “The Guardian” — shields the scalp and strands from pollution and UV exposure, strengthening the hair fibre with microproteins that help reduce breakage.
Saffron — “The Alchemist” — acts as a potent antioxidant, calming inflammation, supporting microcirculation and restoring vitality to tired hair.
Rice Water — “The Healer” — fermented and rich in amino acids, B vitamins and inositol, works to repair the cuticle, improve moisture retention and support long-term scalp health.
The Core Trio performs exactly as promised. One Shampoo deeply cleanses without stripping the scalp, helping to balance the microbiome while leaving hair smooth and light. One Conditioner restores moisture and detangles with ease, improving manageability without heaviness. One Mask offers a more intensive treatment — a richer formula that nourishes and revives hair from root to tip, ideal for weekly use or post-travel repair.
Where The One System becomes particularly relevant for modern lifestyles is in its Boosters. Gielly Green identified four primary concerns: scalp health, bond repair, heat protection and shine.
The One for Scalp soothes irritation and supports healthier growth.
The One for Strength focuses on bond repair and elasticity, reinforcing the hair fibre.
The One for Smoothness locks in moisture while offering protection against heat and frizz.
The One for Shine delivers lightweight nourishment, sealing split ends and enhancing natural brilliance.
Each Booster is non-sticky, layerable and designed to integrate into daily routines without fuss.
Fragrance is subtle and clean — salon-fresh without being intrusive. It carries a refined, almost understated character that won’t compete with your cologne, instead sitting quietly in the background. It feels considered, much like the system itself.
For the man who prefers clarity over clutter, Gielly Green’s The One System offers a structured, intelligent approach to haircare — distilled down to what matters.