16) How we test at-home hair color
18) What to look for when shopping for the best at-home hair color
19) Which type of box hair dye is best?
20) Are home hair dyes as good as professional hair color?

16) How we test at-home hair color

The GH Beauty Lab regularly tests at-home hair dye with both consumer testers and in controlled Lab tests. In the Lab, our scientists dye human hair samples in black, brown, red and blonde shades and visually evaluate each for color results and gray hair coverage.

They then assess each hair dye's color retention with a series of tests including 20 wash and dry cycles using the Swatch Wash Station (above) and 10 hours of UVA light exposure with the Q-Lab QUV Accelerated Weathering Tester (simulating four weeks of wear). Finally, Beauty Lab scientists measure color change in the dyed hair samples using the VeriVide DigiEye system (below) to determine how much each faded over time.

18) What to look for when shopping for the best at-home hair color

Here's what you'll want in a typical at-home hair color kit (and should have on hand before application), according to GH Beauty Lab experts:

✔️ Hair color: This container holds a blend of the alkalizer and the dye precursors, the molecules that form the final color molecules in hair.
✔️ Developer: Usually housed in an applicator bottle, the developer contains hydrogen peroxide and is mixed with the hair color before application.
✔️ Instructions: Each product is different, so read the directions fully before use to familiarize yourself with the process, and follow them closely for best results. Lay out tools before starting for easy access.
✔️ Gloves: One set is often included to protect skin from dye, but have extra gloves on hand just in case you need to switch them out for a different size or a fresh pair.
✔️ Applicators: Most kits come with an applicator bottle in which the developer and the color are shaken together. Some also include a mixing tray or bowl and an applicator brush. If not included, gather a bowl to dispense the dye into, an applicator brush and clips to section hair to ensure even coverage.
✔️ Extras: Kits may have packets or tubes of color-protecting shampoo, conditioner or a deep-conditioning treatment to enhance the result. Some also include color-remover wipes to sweep away dye splatters and a shower cap to slip over your hair while the dye processes to prevent dripping. (If not, GH Beauty Lab pros recommend having your own ready.)

19) Which type of box hair dye is best?

Choose your hair dye formula based on how long you want the color to last and your desired results. Aral shares a quick primer:

Permanent: This dye often contains ammonia (to open hair’s cuticle) mixed with a developer (hydrogen peroxide) to lift and deposit pigment, changing the hair’s color until it grows out. This dye lasts the longest and is best for covering grays.
Demi-permanent: Ammonia-free, it deposits dye with a developer and lasts up to 24 shampoos for subtle enhancement and blending of regrowth.
Semi-permanent: It has no ammonia or developer and deposits dye only to soften gray or boost color, lasting through about six to eight washes.
Temporary: This is both ammonia- and developer-free, which means it's the least damaging hair dye. Large color molecules adhere to the outer layer of strands and can be washed out in one to two shampoos.

20) Are home hair dyes as good as professional hair color?

Yes, high quality at-home hair dye formulas like those recommended here can provide results equivalent to salon hair color, including gray coverage, GH Beauty Lab experts say. That being said, if you are interested in more intricate hair color like lowlights, extensive highlights, balayage, ombré or a drastic color change, it's best to visit a salon professional who is trained in those techniques.