What’s in the Vial?

What's in the vial?

Peptides are built one amino acid at a time. Every step can fail, and the misses add up. Pick a molecule, set how often each step works, and see what a batch looks like before anyone purifies it. Then see who has to answer for it.

This is an illustration of synthesis math, not a measurement of any product. The share of full-length chains is the per-step success rate raised to the number of coupling steps (one fewer than the chain length), assuming nothing is purified. Read the slider as the overall success rate for each amino acid added, counting every way a step can go wrong. A single coupling reaction typically works better than 99.5 percent of the time, but incomplete deprotection, deletions and side reactions add their own losses, and in crude batches of peptides about 15 amino acids or longer, the by-products often outweigh the target peptide (Kent, Journal of Peptide Science, 2025). Real processes vary, and some approved peptides are made partly in living cells. The accountability column describes what the law requires, not how any single company performs. From the Journal essay "Research Use Only. Human Use Anyway."