My son is 10 months old. He has been doing really well with his phe levels, with no restrictions. We had genetic testing done which shows that he does have pku, so no chance he’ll out grow it. Since we know that for sure, his dietician had us start him on the phe free formula to get him used to the taste. We know with his last test that he tolerates 800mg, which is a lot, so we have to stay at that number. That’s a big adjustment for us. His numbers are usually 3-4 with us testing every 4-6 weeks. The doctor mentioned the term hyperphe, but there are so many variations of cpku.