Are you worried about connection between cancer and anything that stops telomeres from doing what they do unnaturally?
No impact on telomeres directly. The slowing of physiologic-processes results in adding of base pairs.
lol no. It’s available to consumers. Heavy water is used as a reactor coolant in unenriched U-reactors (PHWR).
How did you arrive at the 4-oz (~$160!) daily dose? I ask because I never even heard of D20 until I saw your thread, and because the first link I saw on the topic of drinking it suggested no more than 5 tablespoons a day: https://www.technologynetworks.com/analysis/news/heavy-water-reveals-cellular-secrets-307299
My wife's BFF's dad is a nuke physicist with Fermilab. He calculated a safe dose based upon mg/m^2. Edit: It was the max dose based upon my stats (6'3" at 250) that he was comfortable recommending.