Serena Williams is part of a growing cohort of people using peptides like GLP-1 drugs for longevity, recovery, and performance — not just weight loss. The GOAT is bounding out of retirement. Tennis great Serena Williams is back in the game, after openly endorsing GLP-1s for weight loss, and emphasizing how great her knees feel at her new, lower weight. "I'm moving better on Ro," she said in a Super... [6799 chars]