Hydroxyethyl-p-phenylenediamine sulfate

Also known as: HPPS; hydroxyethyl PPD; 3-(2-hydroxyethyl)-p-phenylenediammonium sulfate

INCI name: Hydroxyethyl-p-Phenylenediamine Sulfate

What it does

A PPD derivative used as a primary colour-former in permanent dyes, often in products that avoid PPD itself.

Benefits

Forms lasting colour, and in one German clinic study far fewer patients reacted to it than to PPD (0.9–2.3%, against about one in five of the same patients).

Concerns & Risks

Still a known sensitiser and it can cross-react: 12% of the PPD-allergic patients in that study reacted to it. It may suit some people who cannot use PPD, but only after testing by a dermatologist.

Comedogenic rating

0/5

Non-comedogenic (0)

Suitable for

People without hair-dye allergy; some PPD-allergic people under a dermatologist's supervision

Avoid if

You have reacted to a hair dye or black henna tattoo, unless a dermatologist has patch-tested you with this ingredient

Typical concentration

EU maximum 2.0% on the head after mixing (calculated as the sulfate). India and US: no specific limit verified.