Is 3% a typical concentration of hydrogen peroxide for home use?

February 7, 2016 7:49 AM

I'm from the US and living in Europe at the moment. I'm used to being able to buy hydrogen peroxide at the local CVS at home, but here it can only be bought in a pharmacy. When I bought some the other day, the clerk seemed to be saying that I could only buy a limited quantity, and gave rather specific instructions for diluting it. Now I'm nervous about using it because I don't want any skin injury or anything from using it. Can someone give me some guidance?

Normally in the US I keep a bottle of hydrogen peroxide on hand, mostly for taking blood stains out of clothes (works great!), and the occasional small cut, etc. Recently, I had a guest at a party dump a whole glass of red wine on a table cloth, and after washing, a noticeable mark remains on the cloth. The most promising stain-removal option I found online involves a mix of hydrogen peroxide and dishwashing liquid, which is why I went out to buy some.

In the US, I never considered the hydrogen peroxide you pick up at the drug store to be any kind of potentially harmful substance, but the attitude of the pharmacy staff made it seem like I was doing something really out of the ordinary by trying to buy some for personal use. (BTW, I'm not fluent in the language, just enough to get by, basically.) First, she brought out one very small bottle (just about 100ml), and when I asked for more, she said she could only sell me a maximum of two bottles (and she rang them up separately on separate registers). She also asked me what I was using it for. Whens he handed it to me, she said I should use 15ml in a glass of water. These instructions are also written on the bottle.

Now, because of language difficulties or cultural differences, she may not have understood me when I said I wanted to use it for cleaning, or perhaps I didn't understand her answer. But after searching online, I'm not clear whether what I've bought is a "normal" strength concentration. Or alternatively, could it be that the concentration will be 3% after diluting it as instructed? In any case, I just thought I'd double check just to be safe.

[PS, not too worried about ruining the tablecloth -- the wine stain, if I can't get it out, takes care of that.]

posted by leticia to Home & Garden (15 answers total)

3% is indeed the usual concentration for off-the-shelf hydrogen peroxide in the U.S.

Even in the U.S., some stores stock 35% food grade hydrogen peroxide, and it's possible to buy it in higher concentrations, so maybe you got some 35% or 50%?
posted by straw at 7:57 AM on February 7, 2016 [1 favorite]

Can you post a photo of the bottle label and the instructions? What language is this all in?
posted by DarlingBri at 7:58 AM on February 7, 2016 [1 favorite]

3% hydrogen peroxide is common for disinfecting wounds, you can find this for sale in supermarkets even, so I'm not sure why they would only sell you two bottles. Which country are you in?
posted by 0cm at 7:58 AM on February 7, 2016

Response by poster: I'm in Hungary - the instructions are handwritten in hungarian.
posted by leticia at 8:28 AM on February 7, 2016

I looked it up on my pharmacy's website, and they said to dilute 3% hydrogen peroxide with 1-3 parts water for any domestic use.
As far as I can see, hydrogen peroxide is quite strictly regulated by the EU, mainly to stop people from using it for bleaching their teeth.
posted by mumimor at 8:33 AM on February 7, 2016 [3 favorites]

Best answer: Anything more than 30% is considered an explosive precursor. The EU as well as many other countries are considering or may have already limited its sale. There's no concen for 3%, that's the typical domestic use strength. However it would not be the first time a clerk whose read a security note has been over-cautious.
posted by bonehead at 8:34 AM on February 7, 2016 [1 favorite]

Maybe they're more strict in the East, but by "handwritten" do you mean the pharmacist wrote them on the label, is there anything from the manufacturer, or did they fill two bottles with hydrogen peroxide and give you the written instructions? It's possible, as you say, that the bottles have a higher concentration and thus need to be diluted for general use, in which case, in the absence of a manufacturer's label with the ingredients/concentration, I would just follow the advice given by the pharmacist or just go by the pharmacy again and ask them directly.
posted by 0cm at 8:48 AM on February 7, 2016

Hydrogen peroxide is no longer advised for cleaning wounds. See, for example, "Cuts and scrapes: First aid" by the Mayo Clinic.
posted by grouse at 8:50 AM on February 7, 2016 [7 favorites]

That advice would not stick in a lot of European countries, where hydrogen peroxide and povidone-iodine are routinely used and recommended for the disinfection of superficial wounds. Also, about the latter, there are conflicting studies about toxicity, and one study in particular hints at the ability of povidone-iodine improving scar tissue regeneration. So pick your favorite stand and run with it, I guess?
posted by 0cm at 8:54 AM on February 7, 2016 [1 favorite]

Response by poster: Ocm: It's packaged (bottled) by the pharmacy, with instructions handwritten on the label.

Image here (pen for scale :D )

mumimor and bonehead: Good points. So it seems like I'm fine for using this just as I would the bottle I would buy in the US.

grouse: thanks for the link. Didn't realize that. Will definitely read!
posted by leticia at 9:42 AM on February 7, 2016 [1 favorite]

It does say 3%, but I'd just follow the directions, to be on the safe side.
posted by 0cm at 9:51 AM on February 7, 2016

Nthing most likely (explosive ingredient+terrorism hysteria) x inconsistent and bumbling safety officials
posted by sexyrobot at 9:58 AM on February 7, 2016 [1 favorite]

Hydrogen peroxide is not the only form of oxygen bleach available. If you find you don't get anywhere with the small quantities available to you, perhaps you could try one of the many products made for soaking nappies before laundering; most of those contain an oxygen bleach that should be more than adequate to deal with a red wine stain on white cloth.
posted by flabdablet at 10:03 AM on February 7, 2016

Is it possible that what's in the bottle is a much higher concentration and that following the directions will dilute it to 3%?
posted by ROU_Xenophobe at 10:26 AM on February 7, 2016

Three percent is indeed the "typical" concentration in US bottles. If the bottles you have are higher concentration, the oxygen-producing reaction will be more vigorous than usual. I wouldn't put it on my skin if I wasn't sure, but I might pour a few drops down a sink or put a drop of blood in it; since you're familiar with how the 3% bubbles under your normal use conditions that might help you figure out what you have.
posted by tchemgrrl at 11:07 AM on February 7, 2016 [1 favorite]