Olive Young best sellerProgressive gray-toning herbal shampoo

Ryo Double Effector Black Shampoo

Amorepacific

Ryo Double Effector Black Shampoo
Our read

Why our pick wins

A basic-dye toning shampoo on Amorepacific's herbal Black Toning complex, with nitrophenol and basic dyes — no PPD, no peroxide. It also takes roughly 21 washes to build and gradually rinses back out. Ours lands on the first wash and stays; how completely it covers depends on how much grey you have.

Screening score

How they compare

Ryo Double Effector Black Shampoo 8.1 / 10
GDS Hair Dye Shampoo — Grey Coverage in 10 Minutes in the ShowerDHALIORA pick 8.6 / 10
GDS Hair Dye Shampoo — Grey Coverage in 10 Minutes in the Shower See the DHALIORA pick GDS Hair Dye Shampoo — Grey Coverage in 10 Minutes in the ShowerScreening score 8.6 / 10
What's inside

Ingredient breakdown

12 ingredients screened

Low
Conditioning
Low
Anti-Hairloss Functional
Mid
Semi-permanent basic dye
Mid
Semi-permanent basic dye
Mid
Semi-permanent basic dye
Mid
Nitro hair dye (restricted-use)
Mid
Nitro hair dye (restricted-use)
Mid
Preservative
Low
pH Adjuster
Low
About this comparison — This is an editorial, factual comparison. Ingredient risk reflects our own reading of publicly available safety data, an EWG-style reading. DHALIORA is not affiliated with, endorsed by, or partnered with the competitor brand. Nothing here is medical advice — always read the packaging and patch-test where indicated.