1DK Repair Treatment
Upcycled from waste materials in furniture production, this natural oil is sourced from Hi no ki in the Tōkai region of Gifu Prefecture.
Hi no ki essential oil (moisturizing) ※1
The Repair Series features a common ingredient across all products: Hi no ki wood oil. This is not a conventional essential oil, but one derived from wood scraps and branches discarded during furniture manufacturing or left in forests. It is a domestically produced, eco-friendly essential oil that is gentle on hair, humans, forests, and the planet.
Designed to complement the 1DK formula, this unique essential oil is crafted to repair and strengthen hair structure.
Repairing the damaged ‘S-S bond’
1DK PLEX ※2
What is the S-S bond?
The primary component of hair, keratin, contains the amino acid cysteine, which includes sulfur (element symbol: S). The sulfur in cysteine forms many bridges between adjacent cysteine molecules, increasing hair strength. These bonded cysteine units are called ‘cystine,’ and the strong connection between them is known as the ‘S-S bond’ (disulfide bond).
Perming requires breaking the S-S bonds, which weakens the hair structure. Similarly, hair coloring and bleaching also damage some of these bonds.
Features of 1DK PLEX
1DK PLEX helps repair and restore the S-S bonds, reinforcing the hair’s natural structure and improving resilience.
| Package Size | Quantity |
|---|---|
| 200g | 1 unit |
| 480g | 1 unit |
| 800g | 1 unit |
※1 Hi no ki wood oil
※2 1DK PLEX
FAQ
What makes Hi no ki wood oil different from regular essential oils?
Hi no ki wood oil is upcycled from wood scraps and forest branches, making it a sustainable and eco-friendly option. Unlike traditional essential oils, it is derived from waste materials in furniture production and is designed to be gentle on hair, humans, and the environment.
How does 1DK PLEX help repair hair damage?
1DK PLEX targets the S-S bonds in keratin, which are weakened during chemical treatments like perming, coloring, or bleaching. By repairing these bonds, it helps restore hair strength and resilience.
Is this product suitable for all hair types?
This product is designed for hair that has undergone chemical treatments or experiences frequent damage. It may be especially beneficial for dry or weakened hair, but results may vary depending on individual hair conditions.

Brian Dowd –
After using this treatment regularly, my hair feels noticeably stronger and less prone to breakage. The scent is natural and pleasant, and I appreciate that it’s made from upcycled materials. My hair has regained some of its shine and elasticity after months of chemical treatments.
Elizabeth Harris –
I’ve tried several repair treatments, but this one stands out. The S-S bond repair seems to work well, especially after bleaching. My hair doesn’t feel as brittle anymore, and it holds its shape better.
Karen Murray –
The packaging is practical and the product delivers on its promise. After a few weeks of use, I noticed less frizz and improved manageability. It’s a great addition to my hair care routine, especially for damaged ends.
Felicity Newman –
It works, but I didn’t see dramatic changes. The scent is mild and not overpowering. I would recommend it for those with moderate damage, but it may not be enough for severely damaged hair.
Austin Wright –
I’m impressed by the sustainability aspect. The oil comes from waste wood, which is a positive step. My hair feels softer and more resilient after consistent use. I’ll definitely buy more in the larger size.