Rule #1 in advertising is to make products sound less objectionable than they really are, so you'd expect a bottle of something called "Danderine" to be an anti-dandruff medication that probably smelled godawful and burned like hell as you dumped the goo on your flaky scalp. Not at all; for about a half century, Danderine was widely sold, and used as a hair conditioner and styling gel that smelled like aftershave lotion.
In the first years of the 20th century, the company promoted it as a "hair-growing remedy" safe enough for children, such as the manufacturer's daughter seen in this 1906 Santa Rosa Republican ad. In the 1910s, newspaper and magazine ads portrayed young women with waist-length tresses, and the implied promise that using the stuff would make your hair easier to style in the late Edwardian bouffant fashion. Danderine's heyday apparently came in the 1920s, with ads that targeted women with shorter, bobbed hair. Danderine was now a "one-minute hair beautifier" that would make your hair "appear twice as heavy and plentiful."
The "twice as heavy" claim could well be true, after it was used for a few weeks; a 1907 analysis found that about five percent of the borax and glycerin in the formula never evaporated, staying behind in your hair as residue. A later chemical analysis found Danderine was mostly alcohol, with glycerin, boric acid and resorcin (the anti-dandruff part of the formula), salicylic acid (aspirin), capsicum (pepper), and apparently cantharidin, a potentially lethal chemical that's infamously known as "Spanish Fly."
Danderine was so well-known that its advertising claims were repeated like folklore. A 1919 book on public health has the story of a rural Kentucky woman claiming to know someone who hadn't washed her hair in 28 years, yet "had a beautiful suit of hair that reached clear to her knees... [because] every morning she combed her hair with a large comb which she had dipped in Danderine."
Danderine was sold at least through the 1940s, and was followed in the later half of the 20th century by "Double Danderine" shampoo, which promised to "kill the [dandruff] germ on contact. "