HOW does lemon juice lighten blond hair?

I'm looking for the scientific answer here. How does lemon juice work to lighten hair? Is there some kind of chemical reaction that takes place, or something to do with the acidity?HOW does lemon juice lighten blond hair?
Hair colour molecules are inside the hair shaft. They are part of the hair. The whole bundle of hair protein chains is covered by a translucent layer of cells called the cuticle. Light (and colour) shines through but you do not actually see through it.



When your hair is damaged, this protective layer is lifted or often removed. This exposes the insides of your hair to the elements. And with frequent shampooing, with exposure to sunlight and heat, parts of the inside of your hair come out. The hair is weakened. Colour molecules are lost too.



The real sign of damage to hair is loss of colour. Your ends are lighter than the roots because of damaged ends. The ends of the top layer are lighter than hair at the back of the head hidden under layers of hair -- because the ends are exposed, while the back hair is protected from damage.



Lemon juice or any acid will eat away at the hair, damaging it and removing the protective layer. Acids have the ability to change the colour of many things, hair included. Yes, it is a chemical reaction and the bleaching that occurs is permanent. You will find the hair becomes rather stiff and brittle and rough. The acid will continue to eat away at the hair long after you have stopped using it. You never know what the resulting colour will be, especially with dark hair. Light blondes have so little colour in their hair that any lightening makes it get lighter or white.



Sun-In is the same thing. The strong acid is peroxide, which has the ability to eat away at the hair in the same way. It also leaves the hair is the same damaged condition -- but lighter!!HOW does lemon juice lighten blond hair?
Lemon juice alone won't lighten hair, but it will in combination with the sun's ultra-violet (UV) rays. Cut two lemons in half, and squeeze either directly on to clean hair or into a spray bottle, which you can then use to apply the juice to your hair. If necessary, depending on hair length, use more lemons.After applying the juice, use a wide-toothed comb to help dispense lemon juice thouroughly through hair. Then spend a few hours in the sun, wearing sun-protection lotion on any exposed skin. This works best in the summer months, when the sun's light is most direct and the outdoor temperature is pleasant enough to stand for a few hours.
The acid level in the lemon juice strips the residues from shampoos, conditioners, and hairspray from the hair shaft. Blonde hair is naturally very porous, so it grabs mineral deposits from water, which may leave a dulling residue on the hair, also. Lemon juice does not actually lighten the hair. It simply super cleans it, and can also damage it if used too often. If you have blonde, and you want a little more, try a product called Sun In.
Sun exposure will lighten your hair, although very slowly. The acid in lemon juice can help it happen faster. It won't turn dark hair blonde, but it will lighten your hair slightly.



Put some lemon juice on your hair where you want it lighter and go out in the sun. If you have dark brown hair, it probably won't turn blonde but will give you red/auburn highlights. It seems to work best on people who have dirty blonde or light brown hair.



Use it on dirty hair, rather than freshly washed hair. That way the oils in your hair will protect it from the drying effects of lemon juice.
Lemon juice alone does not lighten hair. As most know, being out in the sun can lighten your hair slightly (reason why most have lighter hair/natural highlights durning the summer months). My point being, lemon juice combined with direct sun exposure will give you increased results due to the high acidic levels of the lemon juice.