TL;DR: It didn't work for me. I consistently bleach my hair. I'm not trying to come off as blonde, I just like the look of obviously bleached hair better than I like my natural color, so I generally only re-bleach once every five months or so.
This is a picture from after the lemon juice, but before the sunshine. Lemon juice definitely works as a gel, at least in my hair, which is naturally pretty spiky but nothing like this.
I didn't wash my hair before I started this process, and that might be part of why it didn't work.
The lemon juice was rubbed into my hair thoroughly -- my hair was totally saturated when we left.
We went for a half-hour long walk in bright sunlight. I'm sure I took a picture while we were out, but I might have hallucinated that because it isn't there. So, possible side-effect: Hallucinatory photography.
Here's how my hair looked at the end:
This is a much better picture of how awful my hair looks without bleach. It's also a clear demonstration that lemon juice didn't work for me.
Here's the part of my highly scientific experiment in which I point out potential flaws:
- Maybe lemon juice doesn't work for everyone -- a sample group of one is not exactly representative.
- I got a lot of mixed answers online about whether my hair should be clean. I went with dirty, and it didn't work. Maybe if I'd showered right before, I'd have had better results.
- I used bottled, store-bought lemon juice. It's possible that fresh lemons are necessary for successful bleaching. (Though I read that it's supposed to be the citric acid that makes it work, and bottled lemon juice is sour as ▓▓▓▓.)
- I was only out for a half an hour. Maybe it would have worked more noticeably if I'd spent the entire day in bright sun.
I made this post because when I was looking for information, I couldn't find any pictures of actual people who've tried it. If you are planning on trying lemon juice as a hair lightening method, I recommend it -- do it, and take pictures. Post those pictures online, or send them to me if you want them uploaded. I'll obscure anything that looks identifying about them and start a gallery.