A patch test is a small trial run. You put a little of a new product on a patch of skin you can keep an eye on, wait, and check for a reaction before it goes anywhere more sensitive. For a leave-on product meant for intimate skin, that means a small amount on the inside of your forearm and a 24-hour wait. The effort takes seconds; the waiting is the hard part.
Why patch test a new skin care product?
Because any skin care product can disagree with someone's skin. The NHS lists cosmetics among the products that can cause allergic contact dermatitis, which makes skin itchy, dry and cracked, and sometimes blistered. The American Academy of Dermatology points out that one ingredient, such as a preservative, can be enough, and that testing a product on a small area first can help predict whether your skin will react.
A forearm with an itchy red patch is a nuisance. The same reaction on intimate skin is far harder to ignore, which is why every not yet. product asks for a patch test before first use.
How to do a patch test, step by step
- Choose your spot: the inside of your forearm. Make sure the skin there is clean, dry and unbroken.
- Apply a small amount. For a spray, spray once onto the inside of your forearm. For a cream or gel, put a little on a fingertip and apply it to a small patch.
- Leave it alone. Try not to rub, scratch or wash that patch while you wait.
- Wait 24 hours before first use.
- Check the skin. Look for redness, itching, swelling or a rash. If you notice any of them, don't use the product. If the skin looks and feels normal, you can use it as directed.
All three products in the range carry this same 24-hour forearm test in their directions: the not yet. Intimate Skin Care Spray, the Intimate Skin Care Cream and the Intimate Skin Care Gel. Before you start, check the ingredients on the pack, and don't use a product if you know you're allergic to any of them.
How long does a patch test take?
For not yet. products, 24 hours: apply a small amount to the inside of your forearm, then wait a day before first use. Other products set their own time, so follow the pack.
If your skin reacts easily, there's no harm in testing for longer. The American Academy of Dermatology suggests applying a new skin care product to the same small spot twice a day for 7 to 10 days, and going ahead only if there's no reaction.
Why test on your forearm and not your intimate area?
The inside of the forearm is easy to see and easy to leave alone. The American Academy of Dermatology recommends testing on a spot where the product won't be rubbed or washed away, and names the underside of the arm as one. The same group describes the genital area as sensitive, so it makes sense to find out how your skin gets on with a product somewhere less delicate first.
What does a reaction look like?
A skin reaction can show up as redness, itching, swelling, a rash, dryness, cracking or blisters. On lighter skin it usually looks red. On darker skin, the NHS says it can look dark brown, purple or grey, so go by how it feels as well as how it looks.
With not yet. products, you may notice a gentle cooling or tingling feel on the skin. Redness, itching, swelling or a rash are a different matter: count them as a reaction.
A clear patch after 24 hours is a good sign, but it isn't a guarantee. The NHS says contact dermatitis usually appears within a few hours or days of contact, so keep an eye on the spot, and stop using the product if irritation develops later.
What should you do if your skin reacts?
- Wash it off. Rinse the patch gently with warm water as soon as you can.
- Don't use the product, on your arm or anywhere else.
- Cool it down with a clean, cool, damp cloth if the skin feels uncomfortable.
- Speak to a pharmacist if the reaction is troubling you. They can recommend an emollient (a moisturiser) to stop the skin becoming dry.
- See a GP if the reaction is severe, keeps coming back, or doesn't clear.
Call 999 if your lips, mouth, throat or tongue suddenly swell, you're breathing very fast or struggling to breathe, or your throat feels tight or you're struggling to swallow. The NHS lists these as signs of a serious allergic reaction (anaphylaxis) that may need hospital care straight away.
Is a home patch test the same as a patch test at a clinic?
No. A home patch test checks how your skin gets on with one product. A clinic patch test is a medical test, done in a dermatology department, to find out which substances you're allergic to when you have allergic contact dermatitis.
The NHS describes it like this: tiny amounts of known allergens are taped to your back, removed after 2 days, and the skin is checked again about 2 days later, because most allergic contact dermatitis reactions take that long to develop. The British Association of Dermatologists says it usually means 3 hospital appointments over one week. A GP may refer you for one if you have contact dermatitis and the cause can't be found.
| Home patch test | Clinic patch test | |
|---|---|---|
| What it checks | Whether your skin reacts to one new product | Which substances you are allergic to (allergic contact dermatitis) |
| Who does it | You, at home | A dermatology department (skin specialists) |
| Where on the body | The inside of your forearm | Usually your back |
| How long it takes | 24 hours for not yet. products; other products give their own time on the pack | Usually 3 appointments over about a week; the patches stay on for 48 hours |
| How you get one | Do it yourself before first use | Usually a GP refers you |
Redness, itching, swelling or a rash on a home patch test: wash it off and don't use the product.
Do you need to patch test every new product?
Yes. Dermatologists recommend testing a skin care product before you add it to your routine, and each product gets its own test, even within the same range. A clear result with the spray, for example, doesn't cover the cream or the gel.
After a clear patch test: how to use it
Once the patch has come through 24 hours without any redness, itching, swelling or rash, follow the directions on the pack:
- Use it only on clean, dry, unbroken skin, and not within 24 hours of shaving, trimming or waxing. Our how to use page has the full directions.
- Keep it away from the eyes and the opening at the tip of the penis. It's for external use only.
- Start small, and stop if irritation develops.
Still choosing a format? Our guide to intimate cream or spray for men compares the spray, cream and gel, and what is men's intimate skin care? covers the basics of washing, drying and grooming.
Common questions
How long does a patch test take?
For not yet. products, 24 hours: apply a small amount to the inside of your forearm and wait a day before first use. Other products give their own time on the pack, so follow that.
Where should you do a patch test?
On the inside of your forearm, on clean, dry, unbroken skin. It's easy to see there, and the product is less likely to be rubbed or washed away.
Can I patch test on my intimate area?
No. Test on the inside of your forearm first and wait 24 hours. Only use the product on intimate skin if the patch shows no redness, itching, swelling or rash.
What does a reaction to a patch test look like?
Redness, itching, swelling, a rash, dryness, cracking or blisters. On darker skin, the NHS says it can look dark brown, purple or grey rather than red.
What should I do if I react to a patch test?
Rinse it off gently with warm water and don't use the product. Speak to a pharmacist if it's troubling you, see a GP if it's severe or doesn't clear, and call 999 if your lips, mouth, throat or tongue swell or you struggle to breathe.
Is a skin care patch test the same as an allergy patch test?
No. A home patch test checks one product on your forearm. A clinic patch test is a medical test in a dermatology department that finds which substances you're allergic to, usually over 3 appointments in a week.
Do I need to patch test every new product?
Yes. Each new product gets its own patch test, even within the same range, because a clear result with one doesn't cover another.
Sources
General information for adults 18+, not medical advice. If a skin problem doesn't settle, or you're worried, speak to a pharmacist or GP.
