Guide
Hydrocolloid tape: what you’re buying, and how to make it stay on.
Skin re-surfaces faster under a moist dressing than under a dry scab, with less inflammation and noticeably less pain. One review of the dressing literature found roughly three quarters of studies reported better re-surfacing under moist dressings than dry ones.
That finding is the whole reason hydrocolloid (a wound-dressing gel) exists, and it has been settled since a 1962 experiment first demonstrated it. Hospitals have used the material since the 1980s.
Hydrocolloid tape is that material, sold by the metre. If you’re reading this you’ve most likely met it already, as a pimple patch or a blister plaster, and you’re here because you want more of it and in a shape of your own choosing.
What you’re actually buying.
Hydrocolloid isn’t a drug. There’s no active ingredient and nothing antibacterial in it. It does two things, both physical, and they’re the reason it behaves so differently from a plaster.
It absorbs. The gel draws fluid out of a weeping spot or a broken blister and holds onto it. That white swelling after a few hours is the fluid, now held in the dressing.
It seals. Whatever is underneath is covered, and dirt, friction and your own fingers stay outside. Sealing is where the research sits, and it’s what the opening paragraph is describing: a wound held moist and covered closes over faster than one drying into a scab in the open air.
MEND’s roll is 5cm wide, in 1, 3 and 5 metre lengths. It’s the same hydrocolloid that’s in the patches — just thicker, and not cut yet. It works on pimples too, including the ones on your back and chest.
Four steps
How to make it stay on.
Most of the complaints about hydrocolloid are really complaints about application. Four steps, and the first two are the ones people skip.
- 01
Clean it and dry it properly.
Hydrocolloid won't stick to damp skin. If you've just showered, wait.
- 02
Cut a piece bigger than the problem.
Aim for a centimetre of ordinary skin all the way round — the border is what holds it on.
- 03
Round the corners.
Square corners catch on socks and lift, and this one small thing is the difference between a dressing that lasts a day and one that lasts an hour.
- 04
Press it on with a warm hand and leave it.
Thirty seconds of body heat helps it bond. Then leave it. Change it only when it won't stay on anymore, usually a day or two.
Peeling it off early to look resets the clock. Everyone does it anyway.
On a heel or the side of a toe, cut a long strip. A rub along the edge of your foot is a line, and a line is what you want covering it.
Against Compeed and the branded ones.
Compeed and the other branded blister plasters are hydrocolloid too. Same material class, pre-cut into blister shapes, priced to match. If the shape suits your blister they work, and there’s no point pretending otherwise.
There is one trial worth knowing about. 604 runners at four French sporting events wore a hydrocolloid plaster on one foot and a regular fabric plaster on the other. Blisters or hot spots formed under the hydrocolloid 14.5% of the time, against 25.5% under the regular plaster. It was funded by the company that makes Compeed, with several of their staff among the authors, so weigh it accordingly — but what it tested was the material, and the material is the same one on the roll.
The difference a roll makes is the shape and the quantity. A fabric plaster is a pad and an adhesive: dry, and on a weeping spot it bonds to the wound and takes the new surface with it when you pull. Hydrocolloid holds the moisture in and comes away from the new skin without taking it. A metre of 5cm tape is a lot of dressing, and if you go through them the maths isn’t close.
Stopping and treating blisters on the trail is its own guide — read that one if it’s the blister you came here about.
The honest part
Where it’s the wrong answer.
It isn’t an antiseptic. The Cochrane review went further than you might expect here — hydrocolloid dressings impregnated with silver or iodine healed no better than plain ones. If something is already infected, with spreading redness, heat, pus, or you feel unwell, sealing it is the wrong move. That’s one for a doctor.
It doesn’t do much for a dry spot. No fluid, nothing to absorb. It’ll still cover it and stop you picking, which isn’t nothing.
It doesn’t reach under the skin. A deep, hard lump isn’t touched by something sitting on top of it. That’s what microneedle patches are for, and which patch you need is a separate question.
And it won’t stop a scar by itself. The moist-healing research does link a moist environment to better scar quality, but that work is on surgical and burn wounds. No study shows a dressing prevents an acne scar. What it reliably does is stop you interfering, which is the part you can control.
Deep cuts, burns, anything you’d show a nurse — not this. Tape is for surface skin.
Questions people actually ask.
Is there actual research behind this?
Yes, and it's worth knowing what it covers. That a moist, covered wound re-surfaces faster and hurts less than a dry scab is well established. A trial of 604 runners found fewer blisters under hydrocolloid than under a regular plaster. What the research doesn't show is hydrocolloid preventing scars, or treating acne.
Can I use it on my face?
Yes. Cut a piece to fit a spot that's the wrong shape for a dot, or a patch of several.
How long do I leave it on?
Change it only when it won't stay on anymore, usually a day or two. Put a fresh piece on if the area is still weeping.
Will it stop a scar?
It stops you picking, and picking is what leaves most marks. That's the honest version. Nobody can promise you what your skin will do.
Does it work on an open blister?
On one that's already broken, yes. Wash it with mild soap and water, let it dry, leave the loose skin where it is, and cover it. Change it only when it won't stay on anymore; peeling one off early takes the blister skin with it. On one that's still intact, leave the roof on and cover it to stop the rubbing. Spreading redness, heat, swelling or pus means infection. See a doctor.
Is it waterproof?
It holds up to a shower once it's bonded. A swim is past what it will take.