According to one study, high-salidroside Rhodiola rosea inhibits bladder cancer as well as others: "Rhodiola rosea L.: an herb with anti-stress, anti-aging, and immunostimulating properties for cancer chemoprevention".
As well as a lot of other stuff, "Anti-Inflammatory and Neuroprotective Effects of Constituents Isolated from Rhodiola rosea", and "Salidroside promotes peripheral nerve regeneration based on tissue engineering strategy using Schwann cells and PLGA: in vitro and in vivo".
It's important to know what you're getting because R. rosea can vary in content between rosavins and salidroside wildly, with Chinese R. crenulata having only rosavins, yet these also have their positives despite an early estrogenic effect: "Rhodiola crenulata induces an early estrogenic response and reduces proliferation and tumorsphere formation over time in MCF7 breast cancer cells".
Doublewood's formula tells you exactly what you're getting, and it works for me because it's anti-fatigue for someone with fibro--not as a "stimulant"--it's anti-cancer, and it generates nerve growth in the memory-and-learning hippocampus.
With all adaptogens, you should take them for a month to get the full effect, particularly with increases in memory. However, as a serotonin promoter, R. rosea shouldn't be taken with SSRIs, 5-htp, or L-theanine, because excessive serotonin can cause "serotonin syndrome", the effects of which are the opposite of what you want out of it, such as insomnia. It also lowers blood pressure, a positive for some but not all, and slightly increases heart rate; however, huperzine A (a promoter of acetylcholine) does the opposite. I take a small amount of it along with Rhodiola once a day.