Will Sun In work to lighten ends that have been semi bleached?

Noooo sun in is terrible. I used it when it was popular in the 90s. It works out harsher cause you leave it in (if it's the same as it was back then). Why not try a bleach bath?

Nooo sun in is terrible. It's pretty much just peroxide/developer and it bakes into your hair, just eating away at it. Doing a low vol bleach bath would be safer and you would get a nicer result from it.

No advice other than to agree not to use it.  I remember trying it years ago in my fringe.  Wore it for a few weeks, got fed up and put a semi permanent through it - it went screaming orange.  So bad it required an emergency trip to the hairdresser!! LOL  And she gave me a good telling off for using it

Please never use sun in.  You'll end up with fried hair that is a strange shade of yellow/orange.  Just don't do it.

Yeah, another voice to say, stay away from the sun in! The late 80s were a nightmare of sun in and perms leaving girls with chewing gum hair. Yuck!

It'll also do all the usual red and yellow stages that normal bleach does. There's nothing magical to stop that. It really should only be used, if ever, when someone had naturally blonde hair that is already on the pale side to add a few highlights.

Agreed... Sun In is worse than bleaching your hair because, with bleach, you rinse it off after a timed duration.  Sun In is like (well it IS) peroxide that is left in the hair until you wash it out, so it's continuously doing damage.

I used Sun In last October in attempts to blast some quick lightening into my hair and, though it wasn't good for my hair and risky to try, I knew what it was all about.  I sprayed it in and used some heat to speed up the lightening, and then it was rinsed out within 20-30 minutes.  And it didn't even do anything to the colour from what I recall, just dried it out unnecessarily!

I've learned an awful lot on here about chemical dyes, but I do have to (sort of) stick up for Sun In
.
I used it a couple of years ago to lighten up my henna (which I'm now growing out) and it DOES say in the enclosed leaflet that you're supposed to wash it out. I keep reading that people don't do that, and it looks like they're presuming the instructions don't tell you to, but the ones I read certainly did. Also some people (in the reviews I've read on other sites) seem to use WAY too much of it in one go.

I used it with the hairdryer, washed my hair again afterwards, and it did definitely work, my hair was a much lighter red.
My hair felt in the same condition afterwards (but of course, henna itself improves the condition of your hair and makes it stronger, I wasn't using the Sun In on virgin hair.

Now I've learned about bleach baths on this forum, that seems a way better option, but I do think Sun In isn't that evil IF it's used sensibly!  🙂

Idk I just think.you'll get a more predictable, more even result doing a low vol bleach bath.

I guess the original intention of Sun In was that you spray onto your hair before you go spend the day out in the sun, then you come in and find you've got a bleach-blonde effect.  So I suppose that's the idea behind it, which makes one think it's not something you put in then rinse out immediately.

I agree with @katiesiepierski that you get a more even result with intentional and more controlled use of lightening agents.

Oh yes, I agree with both of you, bleach baths sound much more sensible.

I suppose a lot of people who use Sun In haven't heard of them (I learned about them from reading this forum)
Also there's a lot of ignorance about how hair dyes work (before I tried Sun In on my henna, I read lots of reviews, and it was amazing how some people expected the blonde to "wash out) and others complained their hair had gone orange (not realizing that hair goes through an orange stage as it lightens)  😮