Nothing will make you smarter in an “increase your IQ” sense. Many things can teach you to make better use of the intellect you have. You can become more aware, more knowledgeable, more experienced, more competent, but not more intelligent. You would have as much chance as “teaching” yourself to become taller, or your eyes to change colour.
Of course, writing a book or producing a course on increasing IQ would possibly make you wealthier. As with the thousands of miracle diet books, there are many people who will believe it to be possible and part with the cover price.