I got it at my local HFS. The "regular" peroxide you buy in the brown bottle in the drug store is 3%. This is 35%, and it says you have to dilute it before use, but it doesn't say what ratio of water to use for internal use (I think it varies by person...). I've never used it as a supplement; I just soak stains in it (diluted with some water, but again, no scientific measuring going on here).
Because it's so much more potent than the regular stuff, I just wanted to make sure it wouldn't corrode the washer or anything!