Exact Answer: Up to 4 hours
Dyeing the hair in different colours is always seen as a major fashion statement and has been in vogue. Some people love to experiment with vivid and vibrant shades while others are just happy with their natural colour with a tinge of difference. People love to experiment with hair colours but dealing with the consequences of the chemicals can be tiresome.
The best solution for this as evidenced by many people is an alternative plant-based natural hair dye, that is, henna. Henna only allows the hair to attain one colour, reddish-brown but it is a popular favourite among its users because of its safety and useful properties for the hair.
How Long to Leave Henna on Hair?
Unlike the hair colour treatments offered at hair salons, henna does not do the job very quickly. It needs to stay on the hair for a much longer time to gain the appropriate results. It needs at least a few hours to soak into the roots and shafts of the hair and bring out the colour properly.
It is also very important to prepare the henna paste correctly before applying it. The powder must be mixed in the correct ratio and left for a couple of hours (overnight) so that it is ready for application. Many people add several other ingredients for a richer colour and more luxurious looking hair, however, that is entirely up to the user.
How long to leave the henna on the hair also depends on the kind of hair dyeing and coverage required:
Highlights
In the case of highlights much less hair will be used as well as a much less amount of henna. Hence the henna will be able to soak quicker and produce good results. So in the case of highlights leaving the henna on the hair for 2-3 hours is enough.
Full hair dye
In the case of dyeing the full hair, a lot more amount of henna is required and the entire scalp and all the hair on the person’s head are coated with henna. Hence it is required to leave the henna on the head for 4 hours.
| Type of hair dyeing | Time |
| Highlights | 2-3 hours |
| Full hair dye | Up to 4 hours |
Why Leave Henna on Hair for That Long?
Henna being a natural hair dye takes longer to be effective. It needs to sit for hours so that henna can properly soak into the roots of the hair and bring out the colour. Even after the henna is washed off it takes up to 48 hours for the colour to show on the hair. This is a process that requires a lot of patience since it is time taking and can also get messy.
It also depends on the user to decide how long to keep the henna on their hair. It might be natural and plant-based but that does not always make it completely safe no matter what. Sometimes it can cause allergies, these allergies can occur if the henna is left on the hair for too long.
The best way to deal with this is to do an allergy test on the skin and hair before using it on the head completely. It is believed that the longer the henna is kept on the head the darker the colour becomes. But this is not always true. In many cases it causes the scalp to dehydrate and become very sensitive.
It is also very important to pick the right kind of henna. Natural henna can only dye the hair reddish-brown or orange in case of grey or white hair. Therefore all the other henna claiming to dye the hair black, burgundy or indigo should be avoided if the user wants to use the real henna for their hair.
Conclusion
Experimenting with hair dyes is always fun but it is important to do it safely and harmlessly. Henna helps in this to a great extent. Despite its certain limitations like providing one colour only and taking a longer time, it is a great choice as a natural hair dye. When using henna as a hair dye it is important to take care of a few precautions.
It is important to pick the correct natural henna. It is also important to prepare the paste with the right ratio of ingredients. And lastly, it should be left on the hair for 2 to 4 hours depending on the need of the user.