They are both risky really. And since there's a lot of instability in both markets, there isn't a more profitable one. I think forex is less risky...Let me give you an example. Lets say you go into forex. I live in brazil so I am going to use our currency as an example. Last year, the dollar was worth 2 brazilian reais. Now it's only worth around 1.7 You suffered a 0.3 loss or made 0.3 depending on which way you were trading it.
With stocks, some can simply sky rocket and earn you double, triple,etc.. of what you invested and some can literally fuck you from behind and make you lose basicly all or most of your investment. Not to mention you have to be on top of the news when it comes to stocks.
I have about 75k worth of stocks invested in Petrobras, the largest brazilian company. They are an oil company. Now, if they have a problem with something or something breaks down, etc... that means that the stocks are gonna go down, which means sell it asap. If they find a new oil source, then that means stocks are gonna go up. So the secret is to be on top of the news depending on what you invested in, and in my experience stocks are way more risky than forex.
If you do decide to learn forex don't buy a scam ebook or get one of those free reports because they only want money and referral cash lol. Hope I gave you some insight.