On Joe Rogan they asked the question: Why did people where powdered wigs? The answer they found said people wore wigs to hide baldness from syphilis because baldness was a sign of having the STD. Is this true? Sounded like bull to me.

First, I'd like to identify the probable source of their answer on JRE, so we can know what we're disputing. Jamie probably Googled "why did people wear powdered wigs," and he probably came up with this result. This article argues that the European syphilis epidemic in the 15th and 16th centuries brought wigs into prominence as a way to cover up the associated baldness and sores.

The answer given on JRE was partially correct. People wore wigs because baldness was shameful, yes. And baldness was shameful partially because of the association with syphilis. But syphilis certainly was not the only reason baldness was seen as shameful, nor was it solely responsible for the emergence of wigs.

I'd like to first acknowledge the temporal connection between syphilis and the emergence of wigs, which would seem to make syphilis a strong explanation. Wigs re-emerged in the 16th century, for the first time since the fall of the Roman empire. Syphilis appeared for the first time in the 15th century. So it would seem, based on timing alone, that syphilis would be a strong explanation.

However, baldness was long seen as shameful, far before the first concrete instances of syphilis in the late 15th century. For example, in the Bible, the prophet Elijah is mocked by some boys for his baldness. In Suetonius' The Lives of the Caesars, he writes that Julius Caesar was greatly bothered by his own baldness, as it "was often the subject of the gibes of his detractors." The Bible, and to a lesser extent Suetonius, were certainly well-known to the European elite. It cannot be said, then, that baldness was only shameful because it was a sign of syphilis.

A much stronger and longer-standing reason for the shame tied to baldness is the association between baldness and old age. Both in early modern Europe, and earlier, hair was a symbol of youth and masculinity, with baldness symbolizing infirmity and weakness. Bald men were frequently depicted as less masculine; "bald-pated" was an effective and frequently-used insult. On the other hand, baldness could also be a symbol of wisdom acquired through long life, as demonstrated by the early modern expression "more hair than wit."

The association between syphilis and baldness in the early modern imagination should not be ignored either. Though not the only factor, syphilis undoubtedly contributed to the shame of baldness. Syphilis was primarily shameful through its association with sexual immorality. Baldness was frequently seen as a sign of infection with syphilis, and by extension as a sign of sexual immorality. In women, baldness was tied with prostitution. In men, baldness was seen as proof of visiting prostitutes. In this way, syphilis was one explanation for baldness, and reinforced the associated shame through a connection with sexual excess.

Later, in the early 17th century, wigs became more and more popular as status symbols. Several European monarchs, Louis XIII for example, wore wigs to compensate for early baldness. This is a strong argument against the argument that syphilis caused the emergence of wigs. Wigs became popular not because the common man wanted to cover up signs of syphilis, but because they wanted to emulate royalty. There is also no evidence that Louis himself was syphilitic.

So, as usual, the answer given on JRE was correct in some senses, though oversimplified. Syphilis was one reason why baldness was seen as shameful, though the stronger connection seems to be between baldness and old age. Syphilis can also be seen as one of the reasons for the emergence of wigs, though a better reason in my opinion is the fashion trend started by various monarchs.

Other sources (not sure if you can access these):

http://www.jstor.org/stable/27867791

http://www.jstor.org/stable/10.1086/ahr.111.3.631