They're easy to apply and less prone to mistakes because they will wash out over time, making them a good way to tone hair or try out new colours without making a significant commitment; but how long does semi-permanent hair dye last?
Semi-permanent hair dye generally lasts 16 - 24 shampoos, but this can vary greatly depending on the condition of your own hair. There are a few different factors affecting the longevity of a semi-permanent hair dye. These include:
- Hair porosity
- Hair dryness
- Contact duration
- Shampoo habits
- Colour darkness
How long any particular type of hair dye will last is largely dependent on how porous your hair is, and this is the most important factor in the longevity of your new colour. Hair that is very porous will soak up a lot of colour and can end up darker than expected.
If you're using permanent dye, porosity can be problematic because all of this colour simply washes out again in quite a short amount of time. Whilst porous hair becomes intensely coloured, it doesn't hold onto that colour due to the way permanent dye works.
Semi-permanent dye, however, works in a different way. This kind of dye stains the hair and it is the stain that creates the colour. This staining is washed off over time and is limited to the outer surface of the hair shaft. When hair is porous, the staining from the dye penetrates deeper than the surface of the hair, causing the colour to last longer. This is why bleached hair will usually hold onto a semi-permanent dye for longer.
Dry hair is a problem of its own in that it can cause your hair to look frizzy and feel rough, as well as be prone to breakage. This problem also affects semi-permanent dye longevity in much the same way as porous hair does.
If you suffer from dryness, your hair colour will generally last longer simply because the hair is more likely to absorb more of the dye and it will have deeper penetration. Thirsty hair soaks up dye just like porous hair.
Usually, it's perfectly fine to leave a semi-permanent colour in your hair for a long time. Even leaving it for several hours is generally okay because a semi-permanent hair dye doesn't cause damage to your hair. You can leave it for as long as you want and the colour will last longer as a result of this extended processing time.
Your shampoo habits refer to how often you shampoo your hair, how many times you apply shampoo when you wash your hair, and the type of shampoo you use. As shampoo removes the staining of semi-permanent dye, you'll notice the colour fading much faster if you tend to shampoo your hair more often.
People who use a stronger shampoo will also see more fading compared to a moisturising shampoo. This is because the latter type of shampoo has less emulsifying power and doesn't remove as much of the colour. If you have oily hair, you shouldn't be using a moisturising shampoo, but if you suffer from dry hair, it may be a good way to make your colour last longer and help prevent the dryness from occurring.
If you want a semi-permanent hair dye to last longer, you will also need to avoid dandruff shampoo and clarifying shampoo. Both of these shampoos are very harsh on the hair and strip out colour more effectively than other shampoos. Whilst they have their uses, they shouldn't be applied to dyed hair unless absolutely necessary.
Lastly, the darkness of the dye used has a direct impact on how long the colour lasts. If you use a darker dye, there is simply far more colour staining the hair. This means that it lasts longer because it takes longer for all the staining to be removed compared to a lighter colour.
As an example, a deep dark blue semi-permanent colour will last significantly longer than a pastel violet colour will. This doesn't mean that you should use a darker colour just because you want it to last longer, but what it does mean is that if you are somewhat undecided on your colour and want to make it last longer, a darker shade is a good way to make this happen.
How to make your colour last longer
From all the information above, you can surmise that there are a few ways to make your colour last longer. These include washing it less often, using a milder shampoo, washing your hair with cooler water, and choosing a darker colour.
If your hair has been bleached, you can take advantage of that by applying the dye right after bleaching as the high porosity and dryness will cause the dye to last significantly longer. As semi-permanent dyes are conditioning, your bleached hair will actually benefit from the resulting application.
How to get rid of a semi-permanent dye faster
It's not without possibility that you may want to expedite the process of removing a semi-permanent hair dye however, and this can be done by reversing most of the guidelines above. Whereas if you wanted to make the colour last longer you would avoid strong shampoos, to remove it quicker you can use clarifying shampoo or anti-dandruff shampoo.
- Types of dye - Find out more about the other kinds of dye available...
- How to prevent hair color fading - Want to keep your color vibrant for longer? Discover how to decrease its loss...
- Hair care: Choosing the right shampoo - The type of shampoo you use is important for preventing fading and improving the condition of your hair. Find out how to choose the right one...
How long does semi-permanent hair dye last on your own hair? Leave a comment describing your hair condition to find out...