Morning. If you have a knee that still aches from an old injury, today's main story is for you. I went through the research on BPC-157, the peptide people reach for when something will not heal, and I will tell you plainly what it has and has not done. There is also good news about kids who were growing too slowly.
In today's emailBPC-157 at a glance.
Can a peptide help a sore knee heal faster?
Short answer:In rats, clearly: a cut tendon healed faster and held more weight. In people, one clinic's handful of knee patients said it helped, and the first injury trials are now being set up.SMALL HUMAN STUDIES
What it is:BPC-157 is a short chain of amino acids built in a lab, copied from a protein researchers in Croatia pulled out of human stomach juice. What struck me reading the research is that nobody has found what it attaches to in the body, and FDA reviewers have written that its targets are unknown. In rats and in cells it grows new blood vessels around an injury and pulls repair cells into the wound faster.
What the studies found: At one Florida clinic, 16 adults with sore knees were given BPC-157, and 11 of those who got it on its own said they were much better afterward. There was no comparison group.SMALL HUMAN STUDIES
In rats whose Achilles tendon had been cut, the treated animals walked better and their tendon held more weight within two weeks than rats given plain saline.ANIMAL OR LAB ONLY
Two trials that compare BPC-157 with a dummy shot were registered in 2026, one for hamstring strains and one after shoulder repair surgery, and the trial registry lists the first as recruiting.OFFICIAL RECORD
If you're curious:The question I would bring to a doctor is what exactly is sore in there, because the answer changes what is worth trying. The trial registry is free to read if you want to follow those new studies.
The honest part:No finished trial in people has tested BPC-157 against a dummy shot for a muscle, tendon or joint injury. It is not approved as a drug anywhere, US pharmacies cannot legally compound it, and sports anti-doping rules ban it at all times.
Read the full BPC-157 pageSources: Knee pain report, 2021Rat tendon study, 2003FDA review, 2026
Kids on a once-weekly growth hormone shot kept growing for four years
Children with growth hormone deficiency came close to average height for their age on a once-weekly growth hormone shot. All 212 started out short and growing slowly, and 162 were still in the study at year four, with everyone on the shot and no comparison group. The most common side effect was pain where the shot went in, and most children made antibodies to the drug with no sign of harm.SMALL HUMAN STUDIES
Nobody measured their final adult height, since only two children finished growing while the study was running.
Source: Hormone journal study, 2026
New studies, trials and rule changes, in one line each.
FDA approved a semaglutide shot for adults with fatty liver disease and liver scarring.OFFICIAL RECORD
Why it matters:Adults with liver scarring now have a second approved option, cleared early on biopsy results while a longer trial finishes.
MOTS-c, a peptide the body makes, protected eye blood vessels in diabetic mice.ANIMAL OR LAB ONLY
Why it matters:Diabetes damage at the back of the eye has few early treatments, and this points to one worth testing.
A pooled look at nine studies in adults with diabetes found no clear drop in heart problems.HUMAN TRIALS
Why it matters:The two trials of the semaglutide pill did show fewer heart problems, though more people stopped it over side effects.
A VA trial will test whether twice-weekly hCG shots are safe in men recovering from a brain injury.OFFICIAL RECORD
Why it matters:hCG is already approved in fertility care, and this trial also measures memory and thinking at 24 weeks.
GHK-Cu resets thousands of genes to a younger state.
Myth.No. That number comes from matching the peptide against a database of gene readings from cells in dishes, not from anyone's skin. No study has shown it works that way in a person. In one trial of 13 adults after laser treatment, raters saw no change in wrinkles or redness, and a 2025 review called the lack of skin trials surprising. In dishes it does raise collagen.SMALL HUMAN STUDIESThe GHK-Cu page
What would you like me to explain next?
- How peptides get approved
- Which ones are approved today
- What a trial phase means
- How to bring this up with my doctor
Subscribers vote with one tap in the email. Results run the next morning.
Talk tomorrow,
Mark
P.S.Know someone who has been nursing the same sore knee for a year? Forward this to them.
The labels.FDA-APPROVEDapproved for that useHUMAN TRIALScontrolled trials in peopleSMALL HUMAN STUDIESfew people, little or no comparison groupANIMAL OR LAB ONLYnot tested in peopleOFFICIAL RECORDan agency, court or trial registry record, not a study resultCOMPANY-REPORTEDthe maker's own numbers, not peer reviewedNEWS REPORTa news outlet's reporting, not a study