L Carnitine 1000 mg Tablets Energy & Fat Metabolism Support* NOW Supplements One of the most notable questions I receive about peptides is around the topic of their safety. Fact is, peptides have been used safely for over a century in conventional medicine! What There's a lot of confusion around peptides and muscle. Here's how I actually think about it. Most peptides don't build muscle directly. They improve the systems that allow muscle to grow. First, Life Extension, Creatine & Acetyl L Carnitine, Energy Plus Ben Greenfield, PhD Directories