Be careful how you use this please.DO NOT leave it on your hair for over 25 minutes no matter what ANYONE TELLS YOU unless you're in a salon or a professional.. And I don't mean professional as in you've bleached your hair before, I mean really, you know what the ingridients do an dhow it effects your hair.If you've Henna'd your hair, be CAREFUL.If there's dye in your hair, BE CAREFUL.If you leave this on dry, damaged, processed hair, IT WILL FRY IT OFF. IT'S STRONG.My hair is undyed and "virgin" and I used this with Wella lightener powder and left it on for less than 20 minutes, my ends still fried. But geez my hair is almost snow white.Be good to your hair, ask for help and coconut oil/olive oil/argan oil your hair before and after treatment. So the day before, and after you rinse and the following 2-3 days. Read more

Do not purchase this expecting the same results as Wella's 20 vol CREME developer. They are not the same. I have been using the creme developer with good results and very little (visible) damage to my hair. When I purchased this, I misread it the "clear" as "creme ", totally my fault. In one use, at the same application and time as I've always used the creme developer, I had so much breakage. My hair needs a serious deep conditioning and protein treatment. I'm lucky I didn't have to cut more than I did to save it. Stick with the creme! It is way less harsh. Read more

I feel bad for this supplier! All the bad reviews -This product has nothing wrong with it! The reason the bottle doesn’t have a safety seal, not filled, dented and wrapped in plastic is due to pressure; it’s combustible! If you fill it to the brim and seal it, it will explode from pressure; especially if shaken! As for the consistency, it will thicken when activated. Don’t expect it to be the consistency of box dye developer... which also btw is usually unsealed and half filled and thickens once activated. Please know what you’re doing by learning the economics and science before ‘messing’ with your hair. Read more

Amending my prior review - I believed that this product was tampered with as there was no security seal and it seemed a little bit low. However, I visited a local beauty supply store to try to determine whether this was normal for this developer and apparently it is. I subsequently used this developer and had no problems whatsoever. It works well. Read more

I’ve seen a lot of reviews about the bottles not being sealed. I was wondering about this, but learned that the manufacturer doesn’t seal these bottles because the ingredients cause pressure. I also bought this product from Sally Beauty Supply and it didn’t come sealed. I’ve used this 20 developer twice and it appear to work fine. Read more

Disclaimed: I have used WELLA Developer for 5 years now. I have used this level of toner (20) for 5 years.The bottle arrived damaged, large dent in the side. Product didn't seem full and watered down. Poured some out to check and it was so watered down it was nearly see through. This developer should be creamy and white. Can't confirm if it was tampered with but I got my refund and threw it out. Read more

the packaging on the outside looked great but the bottle was squeezed and misshaped so bad that I have no idea how the liquid stayed in. Read more

I used the 40 volume with the bleach powder. Ever since I was in middle school I could dye my own hair but there was a lot of damaged that came with it I would buy the cheapest bleach and developer. But now that I'm working and buy something better and doing my research I bought this it made almost no damaged! And that's important to me since I have curly hair and my curls are still bounce and not frizzy like it would be before. Read more