Across 205 first-hand reports, people mentioned a side effect 9 times (about 4 per 100 reports). The most common: potential toxicity, brain fog, fatigue. User reports show what people notice — they can't tell you whether Selenium is safe for you.
“even the nootropics that some communities swear by did nothing for me (some that come to mind - racetams, tyrosine/NALT, NAC, methylated B vitamins...”
“I tried Iodine,SSRI,Selenium,Rhodiola Rosea,Tongkat Ali,Citrulline,Carnivore Diet,Maca but nothing worked”
Conclusion: Conclusions: In people with HT without THRT, selenium was effective and safe in lowering TSH, TPOAb, and MDA levels. Indications for lowering TPOAb were found independent of THRT.
Conclusion: Selenium is effective in reducing CAS and improving the palpebral aperture and GO-QOL in patients with GO. Additionally, it is safe and has promising therapeutic implications. However, further research is needed to validate its long-term efficacy and safety.