Depending on what type of dye you are using would determine the number of times you can re color or change the color of your hair. This also weighs heavily on the overall health of your hair. If you notice that your hair is very dry, brittle, shedding a lot or breaking off, it is not recommended to color your hair until you have remedied those issues.
Types of Hair Colorants
If you are using an at home traditional color, you should always follow the instructions on the box. If you want to do a touch up of color, just at the new growth (the hair closest to the scalp) you can do that once every 4-6 weeks. If it is a color close to your natural color, you can stretch it out even more, if you are concerned with damaging and over processing your hair. But usually, hair coloring will begin to fade around the 4th week after initially coloring it. If you have a color significantly lighter than your own color, you may opt to do your touch up sooner, as many boxed colors have now been formulated in the safest ways possible and attempt to make their products virtually fool proof.
Natural Colors in a Box.
There is a brand of natural colrant called Naturtint that is made of vegetable based ingredients. This product is safe to use more frequently as it does not contain the harsh, drying chemicals in traditional colorants. Naturtint is more expensive, but does a less amount of damage on the hair. It can be found at whole foods stores and online.
There are 2 types of henna, the kind that colors the hair and the kind that conditions the hair. Pure, natural, organic henna only comes in a limited amount of colors. The only color molecule in henna (Lawsonia Inermis) in sufficient quantity to stain hair is Lawsone , which is a red-orange molecule. Any company that claims they create the wide range of henna colors with 100% henna, using roots, bark, or other parts of the henna plant to achieve their colors is being dishonest. Only henna leaves are useful for coloring hair, and other parts of the henna plant do not dye hair other colors. Chemicals, metallic salts or other plants must be added to henna to make any color other than red. These pre-mixed colors are compound hennas. If you buy a box labeled henna that claims to dye hair blonde, brown or black, there is something other than henna in that box. So it is not considered all natural.
Henna is most often used as a conditioner and while it can be used often, it has some capability of altering the color of your hair over time due to sunlight exposure. A henna treatment can be done to the hair once a month, but it also may change your natural curl pattern. Many users find that their natural curl pattern stretches a bit from the use of henna.
Which ever type of hair color you use, use caution in the amount of time you leave it on your hair, and consider also the colors. The darker colors actually have been recorded to do harm to the hair because they are harder to wash out than lighter ones, but the stripping agents in bleaching, lifters and blonde hues can do some damage as well. Just remember, for a touch up, you can do that every 4-6 weeks and for a whole head of color for boxed products, you should do them quarterly (like every 3 months). For Henna or organic colors, some can be done once a month, but read the labels before jumping in. Henna colors are also the most messy and tend to stain more items in your home than boxed hair color.