Demi Permanent vs. Semi Permanent Hair Color: Everything You Need to Know

The two are similar, but not exactly alike.

If you’ve ever had your hair colored at the salon—or taken the DIY route—you’re probably well-aware that the process involves quite a bit of chemistry and science. There’s all kinds of mixing and formulating required in order to achieve your desired shade and look, be it covering grays or adding sun-kissed highlights. To that point, not all hair color is created equal. It’s generally categorized into one of three groups: permanent, demi-permanent, and semi-permanent. Among those three, there’s the most overlap between the latter two, although there are some key differences worth knowing about. Here, top colorists explain how the two are both similar yet still very different.

What is Demi-Permanent Hair Color?

Before we talk about demi and semi, it’s important to first understand what permanent hair color is. As the name suggests, it’s the type of color that will last the longest—it won’t wash out, it needs to actually grow out. Permanent color opens the cuticle, the outside layer of the hair, and is pushed in with developer in order to penetrate into the cortex, the innermost layer of the hair, explains Kristen Fleming, a Chicago-based hair colorist.

Both demi and semi are different. Demi-permanent color won’t lift, or lighten your existing color—it only deposits it, Fleming notes. However, it does get mixed with a developer that contains hydrogen peroxide; this helps to open up the cuticle to deposit the color into the hair, adds Nicole Gache, head colorist at Valery Joseph Salon Madison Avenue in New York City.

What is Semi-Permanent Hair Color?

On the flip side, semi-permanent color doesn’t utilize a developer and simply deposits the color more on the surface of the hair, says Fleming. It’s why it lasts for the shortest amount of time of all three types. To that point….

How Long Does Each of Them Last?

The overarching rule to remember: “Both demi- and semi-permanent color will ultimately fade away, whereas permanent does not,” says Gache. That being said, a demi will last a bit longer, around 24 shampoos, because it does penetrate deeper into the hair, notes Fleming. In contrast, a semi-permanent color will only last for 4-12 shampoos.

Who Should Consider Using Demi-Permanent Hair Color?

It can be a nice option if you have a little bit of gray that you’re looking to cover up and help blend in with the rest of your hair. “Demi-permanent can cover some gray but will still keep your color close to the natural tone,” says Gache. And while it requires upkeep (given its limited longevity), the regrowth won’t be as harsh as it would be with a permanent color, since there will be no dramatic line of demarcation from the new growth. (Still, if you have a lot of gray that you’re trying to camo, a permanent color is still going to be the best option, says Fleming.)

Who Should Consider Using Semi-Permanent Hair Color?

Want to try a color without any major commitment? Semi is the way to go, given how quickly it will wash out. (Again, just keep in mind that it’s not going to lighten your natural color.) It can also be easier to use at home, since you don’t have to mix it with a developer. Semi-permanent is also a nice pick if you want to tone your highlights, notes Gache, though again, just keep in mind that regular maintenance and upkeep will be required to maintain the effect. In related news, no matter whether you go with demi or semi, minimizing how often you wash your hair and using only color-safe shampoos and conditioners when doing so is the best way to prolong your fresh new hue.

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