Patch Test

How-To: 48 Hour Patch Test

4 simple steps.

Quick summary

  1. Mix a fresh sample – 2 ml colour crème + 2 ml developer
  2. Apply to skin – dab behind the ear or on the inner elbow.
  3. Wait the full 48 hours – keep the area clean, dry and uncovered.
  4. Check for redness, itching or swelling – if none appear, you’re good to colour.
Step-by-step guide
1. Measure & mix
  • Unscrew the developer cap without breaking the comb-applicator seal. Pour 2 ml into a clean dish, then close the bottle tightly.
  • Unscrew the colour-crème cap, pierce the seal, squeeze out 2 ml, then recap firmly.
  • Mix the two parts thoroughly and use the mixture straight away.
2. Apply
Using a cotton bud, coat a coin-sized patch of skin, behind your ear or on the inside of your elbow. Let it dry, then repeat two more times, allowing each layer to dry completely.


3. Wait 48 hours
Leave the test area undisturbed so your immune system has time to respond. Avoid washing, covering or touching the spot.

4. Read the results

  • No reaction: proceed with your full colour application, following the kit instructions.
  • Any redness, itching or swelling: do not use the product and seek professional advice if needed.
Good to know
  • You’ll only use 4 ml total, so the unmixed colour crème & developer stay fresh for up to 12 months once resealed and stored in a cool, dry place.
  • Always repeat the patch test 48 hours before every future colour session – sensitivities can develop over time.

Extra tips for best results
Tip 1 – Where to test
Apply behind the ear or on the inner elbow (remove earrings first). These thin-skinned areas give the clearest reading.
Tip 2 – Be patient
Stick to the full 48-hour wait; most allergies take up to two days to appear.
Tip 3 – What to look for
Redness, itching, swelling or a rash = abnormal reaction. If you notice any of these, skip the colour and consult a professional.
Tip 4 – Ready, set, colour
A clear patch test means you’re safe to mix a fresh batch and colour your hair. If any irritation appears during application, rinse out immediately.

Top tip – Repair & nourish
If your strands need extra repair after colouring, treat them with the Aromaganic Colour Revive Hair Mask to restore softness and shine.