If you’ve been wondering about coal tar shampoo on color-treated hair, you’re not alone. Coal tar shampoos like T-Gel are popular for scalp psoriasis, but the label has a warning that worries anyone with dyed hair. Here’s what the warning really means, and how to protect both your scalp and your color.
Why Coal Tar Is a Concern for Dyed Hair
Coal tar is a dark, strong-smelling ingredient. It can slow down the fast skin-cell growth behind psoriasis scale. If you want the full story, read our guide on how coal tar treatments work.
The catch is the color. Coal tar can temporarily darken or tint hair that is light, blond, gray, bleached, or color-treated. Most labels describe this as rare and usually temporary. But it’s a real possibility, and it’s the main reason many colorists steer clients away from tar shampoos.
Who Is Most at Risk?
| Hair Type | Risk of Discoloration | What to Know |
|---|---|---|
| Natural gray or white | Higher | Can take on a yellow or brownish tint |
| Blond or light blond | Higher | Light hair shows tint the most |
| Bleached or highlighted | Higher | Lightened hair soaks up color easily |
| Fashion colors (blue, pink, silver) | Higher | Pale or pastel shades can shift |
| Color-treated brown or red | Moderate | Less obvious, but color can still look dull |
| Natural dark brown or black | Lower | Tint is much harder to see |
Does It Dry Out Hair, Too?
It can. Some people find that tar shampoos leave their hair feeling dry or rough. Using one more often than the label directs makes this more likely. Dryness can also make color look duller. That’s a cosmetic issue, not hair damage, but it’s annoying when you’ve just paid for a color appointment.
How to Use Coal Tar Shampoo on Color-Treated Hair
If your doctor recommended a coal tar shampoo, or it’s the only thing that controls your scalp, you can lower the risk with a few habits:
- Do a strand test first. Put a small amount on one hidden section of hair. Leave it on as directed, rinse, and let it dry. Then check the color in daylight.
- Focus on the scalp. Part your hair in sections and work the shampoo into your scalp, not down the lengths.
- Follow the label timing. Don’t leave it on longer than directed, and don’t use it more often than directed.
- Rinse very well. Leftover shampoo can irritate your scalp and linger on your hair.
- Condition the lengths. Use a gentle conditioner from mid-hair to the ends to replace moisture.
- Use a mild shampoo between medicated washes if your hair feels dry.
- Tell your colorist. They can advise you on timing and tone.
A Tar-Free Alternative to Consider
If you’ve had color shifts, or you’d just rather avoid tar, there are non-tar options for scalp psoriasis. The Dermasolve Psoriasis Scalp Kit is built around a salicylic acid shampoo rather than coal tar. Salicylic acid helps loosen and lift scale, so it’s a different approach from tar.
Best of all, the Dermasolve shampoo is color safe. That makes it a good fit if you have dyed, highlighted, or gray hair and still want to care for your scalp. It’s also gentle enough for regular use once your scalp clears.
When to See a Dermatologist
- Your scalp isn’t improving after several weeks of regular use
- You notice burning, stinging, or a spreading rash
- Your hair is breaking or thinning more than usual
- You’re unsure whether a medicated shampoo fits with a prescription treatment
You shouldn’t have to choose between a calm scalp and the color you love. A strand test, a light touch, and a good conditioner go a long way.
Mike Marenick is the founder of HealFast Skincare and holds the patent for his invention, Ovasome Technology, used in skincare formulations. He began developing skincare products after watching his mother manage psoriasis for decades, and has spent over twenty years formulating treatments for chronic skin conditions. His work has been featured on Home Shopping Network, in two national infomercials, and in more than 300 publications including Vogue, Newsweek, and Allure. He is not a medical doctor — always consult a dermatologist for diagnosis and treatment of skin conditions.
Leave a Reply