Spirulina Helped Runners Last 32% Longer—Here's the Catch
Runners who took spirulina for four weeks lasted about 32% longer in an all-out effort after a brutal two-hour run. The same study found a 10.9% jump in fat oxidation and higher levels of the antioxidant glutathione. But before you stock up, there's a catch: only nine men took part, and the real-world gain was roughly 39 seconds. Here's what the research shows, why it might work, and how to try it safely.
Caffeine + Capsaicin Beat Placebo in a 10K. Capsaicin Alone Didn't
A chili-pepper compound plus caffeine was the only combo that beat placebo over 10 km in a new crossover trial, yet capsaicin alone did nothing. Caffeine drove the statistical effect, and there's no proof of synergy. The dose, 6 mg/kg, works out to roughly 450 mg for a 75 kg runner, which is a lot. Insomnia, anxiety, headaches, and racing heart showed up more often with caffeine. Here's what the 20-runner study found and who should skip it.