The CAA take a dim view on it.
I tried to go on it earlier this year. Went through my AME who pushed it up to the CAA. They wanted full independent endocrinology reports - extra to the prescribing doctor, a full report from the prescribing doctor and wanted to ground me whilst I trial the treatment. They then required endocrinology reviews annually.
It seems they didn't understand it or have a process for it.
However for females that wish to take HRT there is a process and only have to be grounded 2 days I believe...I stand corrected on this.
In my opinion they viewed it as steroids and I just wanted to get ripped. They discounted the improvement in cognitive thinking, sleep, energy, mood, other health benefits...all quite important for a pilot I would say 🤷♂️