Illness, Hair Coloring & Bleaching
A: Being sick alone - such as having a cold or the flu - does not directly affect how hair color or bleaching products work. Chemical processing relies on the product's formula, which doesn't change simply because you are under the weather.
Short-Term vs. Long-Term Hair Changes
Some of these changes happen rapidly. For instance, a sudden fever, medication shift, or hormonal flux can cause your scalp and roots to become noticeably oilier in a short period.Other changes develop more gradually. If you have been ill for an extended period, experienced nutritional deficits, or undergone prolonged medical treatments, the newly growing hair at the root may emerge with a different texture or strength than the rest of your hair.
Since hair grows roughly half an inch (1.25 cm) per month, changes caused by a prolonged illness typically show up only in the new growth at the scalp, rather than along the entire length.
Increased porosity or dryness can cause hair to absorb color much faster than expected. While that might sound convenient, highly porous hair often grabs too much pigment - leading to results that turn out darker than intended, look patchy, or fade rapidly after washing.
Why a Strand Test Matters
If you have been seriously ill, noticed changes in your hair's texture, or haven't colored your hair since before your illness, performing a strand test is the safest approach.Testing a small section allows you or your stylist to preview how your hair absorbs the formula before committing to a full application, preventing unexpected color results and minimizing potential damage.
©Hairfinder.com
See also:
Medications that affect your hair
Can medications make hair not take color?
Can thyroid medicine affect blond hair color?