GLP-1 drugs work. Roughly 3–4 million Americans over 65 may be heading for the part nobody has studied: rapid weight loss, some muscle lost along with it, discontinuation, and substantial regain.
Does repeated platelet donation produce systemic health benefit through hematopoietic renewal? Blood centers have run the experiment for four decades and never asked.
The trait that best predicts cellular longevity is cell-cycle exit. Which means the safest rejuvenation may be the one that resets a cell and then permanently forbids it descendants.