Hi Sarah. I have caught up with the new forum, at last. Transfemme advocate whey protein shakes, but their product is bovine ovary and, if Cheryl1989, who posts here, is correct, its primary effect is to mimic progesterone.
I suspect that the truth is, that if you have a good diet, high in protein it aids growth of all types. As a chef/patron, I probably eat more protein than most, as I cannot bear wasted food and I am happy with my growth. I have found that adding wild yam increases activity. It as a mimic of progesterone and as both oestrogen and progesterone are needed for breast growth, taking wild yam makes sense.
From the old site, the recurring message is that, this journey requires patience; Ardhana's 4 months to reach a b cup is, to put it mildly, unusual.
As long as you are aware of things happening, rest content. If not I would increase the dose by 50% until you are aware of buds, tenderness ect. I once had to do this as I was without a supply of PM for a couple of weeks and growth was reluctant to er-start.
The other thing is to realise that this is not a uniform rate of growth; it happens in fits and starts.
Let me give an example. My right boob lagged behind the left, by quite a lot. The nipple was pierced and I wore a ring. I had lost the piercing in the left a couple of years ago and now the other was showing signs of migrating, so 4 days ago I took it out. Yesterday I noticed that the boob was filling the bra better and, in the afternoon, that it was very tender and the bud was very pronounced. At the start of the week I had some creasing to the right cup of my bra. It was just noticeable, this morning; this afternoon my boob is filling the bra perfectly.

Remember how many years it takes a genetic woman to fully develop her boobs. If you can do it in 2 years that is some going.