Hm.. well I take PABA right now.
From what I heard, it actually helps with breast growth. It synthesizes the hormones similar to what you went through in puberty years, and even girls who took it between the ages 13-15 had a major increase in breast growth (I don't know if this is true, but this is what I've read).
I currently take it along with Saw Palmetto. People have been commenting me on my bigger butt, but nothing in the breast yet. The recommended dosage is 500 - 1000 mg, NOTHING more, as it's a B vitamin and usually an excess of b vitamins gets urinated away anyways.