Patch Test & Strand Test Guide

Two simple tests — done 24 hours before your application — protect you from two different risks: the rare possibility of an allergic reaction, and the much more common surprise of an unexpected color result. Skip neither.

Why Two Tests?

  • Patch test = safety check. Confirms your skin doesn't react to the plant material itself. Although true henna allergies are rare, sensitivities to indigo (or to the Ayurvedic herbs we blend) do occur.
  • Strand test = color preview. Tells you exactly what color the dye will give your hair — at your porosity, your starting shade — before you apply it to your whole head.

Patch Test — Step by Step

  1. Mix a small amount of paste (about a teaspoon) following the instructions for your shade.
  2. Apply a dime-sized dab behind your ear, on the inside of your elbow, or on the underside of your wrist.
  3. Leave for 1 hour, then rinse with warm water (no soap).
  4. Wait 24–48 hours before doing anything else with the product. Watch the test spot for:
    • Redness
    • Itching
    • Swelling
    • Burning or tingling
    • Hives or rash
  5. If you see any of these reactions, do not proceed. Discontinue use and consult your doctor.
  6. If your skin remains calm, you're cleared for application.

Strand Test — Step by Step

  1. Choose a small, hidden section of hair — behind your ear, at the nape of your neck, or in the bottom layer of your hair where it won't show.
  2. Mix and apply paste exactly as you would for your full application — same brand, same shade, same liquid, same waiting time.
  3. Cover the section with foil or plastic wrap to keep it warm.
  4. Let it process for your full intended application time (usually 2–4 hours).
  5. Rinse thoroughly. Do not shampoo for 48 hours.
  6. Check the strand at day 1, day 2, and day 3. Remember: henna oxidizes and deepens over 48–72 hours, so the strand will look different on day 1 vs day 3. The day-3 color is your true result.

When to Repeat the Tests

  • Patch test: repeat before every new product or new shade, even if you've used henna safely in the past. Sensitivities can develop over time.
  • Strand test: repeat any time your hair condition has changed — after a chemical treatment, after a long sun exposure period, when introducing gray, or when switching shades.

Special Situations

  • Pregnant or breastfeeding: consult your physician before using any hair dye, even natural.
  • G6PD deficiency: people with this genetic condition should not use henna without medical clearance — there is a documented risk of hemolytic reaction.
  • Scalp conditions (active eczema, psoriasis, open sores): wait until the condition has settled before applying any hair dye.
  • Recent chemical treatments (bleach, perm, relaxer, keratin): wait at least 2 weeks and strand-test extra carefully.

Five minutes of testing today saves five hours of regret tomorrow. If anything feels off after the patch test, write to us at contact@purahenna.com before continuing.