I don't see too much information on Hibiscus rosa sinensis, except as a pregnancy inhibitor... you sure you don't mean Hibiscus sabdariffa which has a wider medicinal usage?
Hibiscus rosa sinensis is a "hardy" hibiscus in the Malvacaea family...

There are lots of H. rosa-sinensis (tropical hibiscus) at the garden centers come spring.

The flowers are supposedly useful for shining shoes. I wouldn't count on the plant for growing hair.

It's like women with wrinkles... in the beginning, you hope and hope and buy all these products then eventually give in to the inevitable.

I haven't used Hibiscus for anything except putting flowers in a tea, for a very cooling summer drink, but I had a couple pages with information. First link shows ways to use the plant, with a specific part on cultivation (how to grow it).
Plants for a Future.
Second link below specifically lists it as a hair grower and nourisher.
Enjoy! Lynn

Here is a link that might be useful: Bunga Raya

Here is some more information on Hibiscus and more on Hibiscus rosa-sinensis.

From the Bunga Rayans: "The flowers are aphrodisiac, demulcent, emmenagogue, emollient and refrigerant. They are used internally in the treatment of excessive and painful menstruation, cystitis, venereal diseases, feverish illnesses, bronchial catarrh, coughs and to promote hair growth."

Does this mean that if you take Hibiscus internally for a cough, you'll grow a hairy chest?

"We will only reproduce information that we believe to be correct, but we make no claim as to the validity of this information." "We think it works, so buy it - but don't blame us if it's useless."