It's been a couple years since I've stepped foot in a sauna, but I started recently after reading this thread, and let me tell you:
After a hard workout and huge pump, feeling tight and so forth, the sauna completely transformed me, body and brain.
I shed all my clothes but my underwear, no music, just the crackling of the coals in the wood chamber, 170 degrees of dry heat.
After 3 minutes, I began pouring sweat, my breathing focused, my mind cleared, I stretched and felt the toxins releasing, releasing, releasing, dumping out.
After fifteen minutes, I walked out totally calmer and present, practically in a meditative state.
My skin felt softer, healthier and more supple and springy after drying off.
Walked out into the brisk outside air, got home and took a freezing shower after my body temp stabilized, felt amazing.
Even while taking vitamins, zma, creatine, fish oil, piracetam, et cetera, hitting that sauna absolutely cut through everything, all the noise, and I felt really great.
Huge ROI for an easy addition to your workout routine.