How To Use

Simple to use.
Impossible to ignore.

Alert. patches are designed to fit seamlessly into your existing sun care routine. Here's everything you need to know to get the most out of them.

⏱️ Takes less than 2 minutes to set up
Step by Step

Your complete guide
to using Alert.

1
🧴
Apply your sunscreen first

Before touching the patch, apply your sunscreen generously to all exposed areas of skin. Make sure you cover evenly and don't rush — proper SPF application is the foundation everything else depends on.

  • Use at least SPF 30 — SPF 50 is recommended for high UV environments
  • Apply 15–20 minutes before going outside to let the SPF activate
  • Don't forget ears, the back of your neck, tops of feet, and the back of your hands
🕐
Before
Going Out
2
🩹
Peel and stick the Alert. patch

Peel one Alert. patch from the backing and apply it to a visible area of skin — your wrist, forearm, shoulder, knee, or upper leg are all ideal spots. Press gently for a few seconds to ensure good adhesion. Note: some people find the knee or leg stays on better than the wrist or forearm, especially if you have hair on your arms — it's worth experimenting to find what works best for you.

  • Apply to clean, dry skin — not directly over sunscreen
  • Choose somewhere you'll naturally glance throughout the day
  • The knee or upper leg can work better than the wrist if you have arm hair — hair reduces adhesion
  • Avoid placing over joints or areas that flex a lot
  • Press firmly around the edges to prevent peeling
📍
Wrist, Arm
or Knee
3
⏳
Wait 30 minutes — this step matters

After applying the patch, you need to wait at least 30 minutes before the reading becomes reliable. During this time, the patch is calibrating — it's detecting the UV filtering effect of your sunscreen and establishing a baseline.

While you wait, the patch will likely appear slightly tinted or unclear. This is completely normal. Do not worry if it doesn't look perfectly clear immediately — give it the full 30 minutes before drawing any conclusions about your protection level.

  • Set a timer if you need to — this step is important
  • The patch will gradually settle and clear as it calibrates
  • Stay in the shade during calibration for the most accurate result
⏱️
Wait
30 mins
4
⚪
Clear patch = you're protected

After 30 minutes, a clear or very pale patch means your sunscreen is active and working. The UV-reactive compound in the patch isn't being activated, which means your SPF is successfully blocking UV from reaching it.

  • Enjoy your time in the sun — you're covered
  • Keep checking the patch regularly — set a habit of glancing at it
  • The patch can take slightly longer to clear on lower SPF factors
✅
You're
Protected
5
🟣
Purple patch = reapply immediately

When the patch turns purple, your sunscreen has broken down and UV is now passing through to the patch surface. This is your signal to reapply sunscreen straight away — don't delay.

After reapplying, the patch will begin to reset and gradually clear again within a few minutes. You're back to being protected and the patch is ready to alert you again.

  • Reapply generously — don't just top up, apply a full fresh layer
  • The patch resets automatically — no need to replace it
  • Repeat this cycle throughout the day
  • Replace the patch if it's been in water for a long time or if adhesion weakens
⚠️
Reapply
Now!
The 30-Minute Rule

Why you must wait
30 minutes after applying.

When you first apply the patch, the photochromic compound needs time to detect and respond to your sunscreen's UV-filtering layer. During this calibration window, the patch may appear tinted or unclear — don't mistake this for a "reapply" signal.

Think of it like a thermometer placed in warm water — it takes a moment to settle on the correct reading. Give the patch its 30 minutes and it will give you accurate information for the rest of the day.

0
Time 0 — Apply
Apply sunscreen & stick patch
Patch may appear slightly tinted. This is normal — calibration has begun.
10
10 minutes
Calibrating
Still calibrating. Patch may look unclear or patchy. Don't judge protection level yet.
30
30 minutes ← Key moment
Patch settles — ready to read
Patch is now calibrated. Clear = protected. Purple = reapply. Trust what you see from here on.
90
90–120 minutes
Typical reapply window
Most sunscreens start degrading in direct sun. Watch for the purple change and reapply promptly.
Pro Tips

Get the most out of
every patch.

👁️
Put it somewhere visible
The whole point is that you'll notice when it changes. Wear it on your wrist or forearm — somewhere you naturally look throughout the day. A patch you don't see is a patch that won't help you.
👨‍👩‍👧
One patch per person
Each patch responds to the SPF applied to that person's skin. Don't share patches between people — give everyone their own so you get accurate readings for each individual.
🏊
After swimming, always reapply
Water significantly accelerates sunscreen degradation. Even if the patch isn't purple yet, always reapply sunscreen after a swim and wait the 30 minutes again for the patch to recalibrate.
🌤️
Clouds don't block UV
Up to 80% of UV radiation passes through cloud cover. The patch will still react on overcast days. This is a feature — it's reminding you that you still need sunscreen even when it doesn't feel sunny.
🕶️
Check it, don't obsess
You don't need to stare at the patch constantly. Build a habit of checking it whenever you pick up your phone, drink water, or sit down. A quick glance is all you need.
❄️
Works year-round
Skiing and winter sun can be just as damaging as a beach holiday — UV reflects off snow and is stronger at altitude. Alert. patches work in any environment where UV is present.
Do's & Don'ts

Quick reference guide.

✅ Do
  • ✓Apply sunscreen before sticking the patch
  • ✓Wait the full 30 minutes before trusting the reading
  • ✓Wear the patch somewhere you'll naturally see it
  • ✓Reapply a full layer of SPF when the patch turns purple
  • ✓Replace the patch if it starts to peel or lose adhesion
  • ✓Use one patch per person in your group
  • ✓Always reapply after swimming regardless of patch colour
❌ Don't
  • ✗Apply the patch directly on top of sunscreen
  • ✗Judge the reading in the first 30 minutes
  • ✗Assume you're fine just because the patch isn't purple yet
  • ✗Use the patch as a substitute for proper sunscreen application
  • ✗Ignore a purple patch and tell yourself you'll reapply "later"
  • ✗Share one patch between multiple people
  • ✗Forget to reapply after water activities