How to do a skin patch test

Did You Know Any Ingredient Can Cause an Allergy or Irritation?

Yep, even something as seemingly harmless as chamomile or water can irritate someone’s skin.

I know, it sounds wild. Water?! What could be more natural and safe than water? But there are people out there who are allergic to it. This just goes to show that no ingredient, no matter how natural or gentle it seems, is completely risk-free.

Why am I telling you all this? Because the last thing you want is to slather a cream all over your face, only to have it turn bright red and itch like crazy. It’s not fun, it’s not pretty, and it’s completely avoidable.

That’s why brands always recommend you perform a patch test first. It’s there, written on the label. But, let’s be honest—most of us ignore it.

I’m guilty of this, too. Most of the time, I skip patch tests. But when I pick a product with even one ingredient I’ve never used before, I take the time to patch test. Why? Because it’s not worth the risk.

Here’s everything you need to know about patch tests, why they matter, and how to do them the right way:

What Is A Patch Test?

A patch test is a simple way to determine if a product will cause a negative reaction on your skin. It involves applying a small amount of the product to a small area — typically on the inside of your wrist, elbow, or behind your ear.

Why those spots? They’re discreet and easy to monitor. If an irritation or allergic reaction occurs, it’s contained to that small area, making it easier to treat (or cover up with a long sleeve or some jewelry).

Patch tests are like a mini insurance policy for your skin.

Why Should You Do A Patch Test?

Because you never know what your skin might react to.

Truth bomb: You can become allergic to anything at any time.

It’s not a joke or an exaggeration. You could use a calendula cream for a decade without a hitch, only to develop an allergy to it out of the blue. Your skin can suddenly decide, “Nope, I’m done with this ingredient.”

This isn’t as rare as you might think. In recent years, as natural skincare has boomed, more people are complaining about sensitive and reactive skin. Coincidence? I don’t think so.

Here’s why:

• Essential oils are natural but potent, and they can easily trigger allergies if overused.
• Synthetic ingredients like fragrances and preservatives can be just as problematic.

The bottom line? Natural doesn’t always mean safe, and synthetic doesn’t always mean dangerous. You need to test products before they go on your face, no matter what they’re made of.

Don’t wait for a nasty rash to appear — be proactive with a patch test.

Related: 7 Natural Ingredients That Can Irritate Sensitive Skin

Who Should Do A Patch Test?

Everyone should patch test. Period.

But if your skin is prone to sensitivities, it’s non-negotiable. Patch testing is especially crucial if you have:

• Sensitive skin: Your skin reacts to just about everything, so you can’t take chances.
• Rosacea: Flare-ups from the wrong product can be painful and long-lasting.
• Acne-prone skin: Some products can clog pores or worsen breakouts.
• Eczema or dermatitis: Your skin is already inflamed, so introducing irritants can make it worse.

If you’ve had allergic reactions in the past or notice that your skin is more reactive than it used to be, always patch test new products.

Related: How To Deal With Rosacea

How To Do A Patch Test

Doing a patch test is quick and easy. Follow these simple steps:

1. Pick a spot to test: The inside of your wrist, elbow, or behind your ear works well. Choose an area that’s easy to monitor.
2. Apply a small amount: Dab a little product on the area—don’t slather it on.
3. Wait 24 hours: Check the spot periodically for signs of irritation.
4. Look for reactions: Common signs include redness, itching, swelling, or burning.
5. React accordingly:
   • If you notice any irritation, wash the area immediately with water and avoid using the product.
   • If there’s no reaction, congrats! It’s safe to use on your face or body.

How Often Should You Patch Test?

You should patch test every time you introduce a new product to your routine. Even if it’s from a trusted brand or features ingredients you’ve used before, formulas vary.

Other times to patch test:

• If the product formula changes: Brands tweak formulas all the time — don’t assume it’s the same as before.
• If you move to a new environment: Climate changes can affect how your skin reacts to certain products.
• If your skin is feeling extra sensitive: When your skin barrier is compromised, it’s more prone to irritation.

Common Mistakes to Avoid

Here’s what not to do when patch testing:

• Skipping it altogether: It’s tempting to dive right into a new product, but don’t.
• Testing for too short a time: Some reactions take hours to appear — wait the full 24 hours.
• Using too much product: A small amount is enough to test for a reaction.

What Happens If You Skip the Patch Test?

Worst-case scenario: You end up with a red, swollen, itchy face that takes days to heal. Best-case scenario? You dodged a bullet, but you’ll never know if you’re rolling the dice each time you try a new product.

The Bottom Line

A patch test may seem like an extra hassle, but it’s worth it. It only takes 24 hours to potentially save your skin from irritation, redness, and discomfort.

The next time you’re excited to try a new product, take a moment to patch test first. Your skin will thank you.

About Gio

Hi, I'm Gio. I'm a no-nonsense, tell-it-like-it-is skin coach and writer on a mission to help you achieve your best skin day ever - every day. I bust skincare myths and debunk marketing jargon to help you figure out what's worth the splurge and what's best left on the shelf - using science, not hype. I also offer skincare consultations to help you create the best skincare routine for your unique needs.