I have been buying longevity/health related supplements and prescription meds for a long time.
Ages ago (pre-Ali and IndiaMart) I started with some trepidation buying from 4NRX online pharmacy.
I bought nootropics, modafinil, A-retinoin gel, for example, generally one order per year. They are based in Hong Kong now. You get free shipping if you order more than GBP50.
I’ve never had a problem with them in the long association, until now.
As you can see, they have a wide range of prescription meds, with variable availability.
Strangely, they only take Visa card. They put HKD100 in the customs declaration which equates to about GBP10, so I don’t think I’ve ever been charged any extra tax/duty on arrival here in UK.
In my most recent order the quantities all got scrambled up, and I didn’t notice (the smart drugs mustn’t have been working that morning! 
).
When I received the email acknowledgment I realised something had gone a bit wrong and contacted customer support and they responded very quickly: cancelled the order within a half hour.
I tried again the next day after I had ascertained my card had not been charged. It seems there was some order form glitch as the quantities still input wrong. I managed to get the right numbers in the right boxes eventually.
This time when I sent in the order, customer services came back to check that it was correct! I was very impressed. Then delivery was great.
This whole process took 7 days. The revised order was posted on a friday and arrived the following Tuesday in London.
They do have Sirolimus advertised, but they told me it had been discontinued.
I can recommend this suppliers. I wonder if with @RapAdmin 's permission I should contact them and ask for a discount code for RapaNews members?
We might get them interested in restocking Sirolimus if they thought there was a demand for it. Customer Services Email.
I assume they ship worldwide, despite having UK in their name.
[EDIT 3.6.25] @daver Daver is correct, they only ship to the UK.