High-purity peptide therapy

Injection pens for weight loss, recovery, skin, sleep and focus, each made to help you look, feel and perform at your best.

Explore peptides

99.6%

Purity measured, HPLC

Every batch is independently tested for purity.

The purity of your pen is printed on its tube.

Microbes detected, PCR

Sterile.

The laboratory looks for bacteria and other microbes in each batch by their DNA, and every batch we sell has passed.

<0.2

Endotoxin units per mg, LAL

Non-pyrogenic.

Endotoxins, left by bacteria even in a sterile liquid, can cause fever after an injection. Non-pyrogenic means every batch has passed the test for them.

USA

Where every batch is tested

Every result comes from an independent laboratory.

Our peptides are tested for purity, sterility and endotoxins before they are sold.

What is a peptide?

Step 1 of 10

Messages

Your cells are constantly sending each other messages: that you’re hungry, that you’ve had enough to eat, that it’s time to release a hormone. Many of these messages are peptides, which are small molecules your body builds from amino acids. Over the last century, scientists have learned to make these messages too. To see how, and why it matters, start with a single amino acid.

Step 2 of 10

One amino acid

An amino acid is a small molecule in two parts. One part is the same in every amino acid, and it’s the part that links one amino acid to the next. The other part, called the side chain, makes each kind different. Some side chains are drawn to water, some avoid it, and some carry an electric charge. Your body builds its proteins from twenty main kinds of amino acid. Think of them as a twenty-letter alphabet.

Step 3 of 10

The bond

Two amino acids join when the end of one links to the start of the next, giving off one molecule of water. That link is called a peptide bond. Link after link, a chain grows. Every link is made the same way, so the chain has a start and an end, and the order of its amino acids matters, just as the order of letters does in a word.

Step 4 of 10

Peptide or protein

A chain of up to about fifty amino acids is called a peptide. Longer chains are proteins. They fold into intricate shapes and do much of the body’s work, from contracting muscles to digesting food. The largest protein in your body, titin, is about 34,000 amino acids long. The dividing line isn’t strict: insulin, with 51 amino acids, is called both a peptide and a protein.

Step 5 of 10

Messengers

Many peptides work as messengers. Your body releases them into the blood or the spaces between cells, and they travel until they meet a receptor, which is a protein on a cell’s surface shaped to fit one particular signal. When the right peptide fits, the cell responds. Oxytocin, nine amino acids long, is the signal that drives contractions during childbirth. GLP-1, about thirty amino acids long, is released by your gut after a meal and helps tell your brain you’ve had enough.

Step 6 of 10

One letter changes the word

The order of the amino acids decides a peptide’s shape, and the shape decides which receptor it fits. Change one amino acid and the peptide may fit its receptor less well, fit a different one, or not fit at all. Scientists make such changes on purpose, to improve a peptide. Your body breaks down natural GLP-1 within about two minutes. Semaglutide is GLP-1 with two amino acids changed and a fatty acid attached, so the body clears it far more slowly: one dose lasts about a week.

Step 7 of 10

A century of peptide medicine

Until 1922, type 1 diabetes was fatal. That January in Toronto, a teenager named Leonard Thompson became the first person treated with insulin, a peptide, and type 1 diabetes became a disease people could live with. Today more than 80 peptide medicines are approved around the world. In 2023, the journal Science named medicines based on GLP-1 its Breakthrough of the Year, because trials showed their benefits go well beyond weight loss.

Step 8 of 10

Making a peptide

Many peptides are made by chemists in a laboratory, one amino acid at a time. Each step nearly always works, but not quite always. If every step succeeds 99 times in 100, only about two in three chains of forty amino acids come out complete and correct. The rest are near misses: chains missing an amino acid or cut short, which look almost exactly like the real thing.

Step 9 of 10

Finding the near misses

That’s why peptides are purified and then tested. A test called HPLC pushes a dissolved sample through a narrow column packed with fine particles. Each kind of molecule moves at its own speed, so they come out one after another, and a detector draws each one as a peak on a graph. The exact chain makes one tall peak and the near misses make small ones. Comparing the tall peak with the others gives the purity. At 99.6%, about 996 of every 1,000 molecules measured are the exact chain. Every Pure99 lot is tested this way by an independent laboratory in the United States.

Step 10 of 10

Learning the language

Peptides let medicine use the body’s own language. They are messages your cells already know how to read, and scientists can now improve them: making them last longer, or letting one molecule act like two or three natural signals at once. Some, like insulin, have been used for a century; many are still early in research. But parts of ourselves we once took as fixed, like how hungry we feel, turn out to be shaped by messages like these, and medicine can now send messages of its own.

A century ago, none of this was imaginable. And science has only just begun to learn the body’s language.