Would Black Henna Block Minoxidil?

Dear Dr. Rassman,

As a female prone to hyperkalemia, I can’t use spironolactone so I can only use Rogaine. Since I have a pale scalp and thinning black hair, I was hoping to dye/stain my scalp black with indigo and henna to mask the hair loss. Do you think that this would block the absorption of minoxidil?

Thanking for your time

With regular henna ink, I would not think so. Henna ink is essentially henna powder mixed with eucalyptus oil and coffee/tea, and none of those will stop the absorption. It’s commonly used for temporary tattoos (see right).

On the other hand, I’ve read about the dangers of black henna, which isn’t usually henna at all, but rather indigo mixed with chemicals. Ingredients of various black henna products can vary, and the FDA has sent warning letters (like this) about the dangers.

I’m not a henna expert by any means, but I’ve read that so-called black henna can cause severe allergic reactions and skin sensitivities, so I’d suggest researching this stuff a bit more before diving in. You don’t want to end up causing larger problems for yourself.