How do you use peptides for the best results?

Peptides that you swallow almost never reach the bloodstream in usable amounts. Stomach acids and intestinal enzymes break them down, and the intestinal wall barely allows large, water-soluble molecules to pass through. This is the fundamental barrier for almost every peptide supplement or peptide drug taken orally. The vast majority of medically used peptides are therefore administered by injection.

The only proven exception to date is oral semaglutide, the blood-sugar-lowering agent known as a GLP-1 agonist. By combining it with a special permeation enhancer -- a substance that temporarily makes the intestinal wall more permeable -- this peptide does manage to reach the bloodstream. In several large clinical studies in people with type 2 diabetes, it effectively lowered blood sugar and body weight, comparably to or better than other treatments. This is, so far, the only oral peptide formulation to have made the transition to clinical use.

For patients who are tube-fed and tolerate standard nutrition poorly, tube feeding based on broken-down protein fragments (di- and tripeptides) offers a solution. These small pieces are absorbed more easily than whole proteins. There are indications that this improves tolerance, but the precise magnitude of the benefit has not yet been well established.

Researchers are working on ways to improve the absorption of conventional oral peptides. Cyclic peptides are more stable in the stomach because enzymes have a harder time attacking them. Nanocarriers (tiny particles that encapsulate the peptide) and absorption enhancers also help, but these techniques are still largely in the research phase. There is no universal solution that works for all peptides. If you buy an oral peptide supplement without a specialised formulation, the likelihood is that very little of it will reach your bloodstream.