Really Research Review, including the other group

The placebo hair count

Hair counts rose in the placebo group. In a six-month trial involving 45 men with inherited hair loss, the increase was 9.6. The groups receiving a mixture of GHK and 5-aminolevulinic acid recorded increases of 52.6 and 71.5.

That neglected 9.6 is, for me, the intriguing number. It gives the larger numbers something to stand beside. The mixture outperformed placebo, and the comparison makes that finding more interesting than a solitary before-and-after photograph would have been.

There is another companion in this story: the second active ingredient. The trial tested the combination. Assigning the whole gain to GHK would require a comparison the trial did not make; assigning it to GHK-Cu would also change the substance under discussion. GHK is the peptide, while GHK-Cu has copper attached.

I cheer the scalp mixture’s result, with the credit for its ingredients still undecided. This is an encouraging human result for a particular scalp mixture. A separate test of its ingredients would tell us which part deserves the credit.

Semaglutide against another medicine

A different companion changes the semaglutide story. In SURMOUNT-5, involving 751 adults with obesity, mean weight changes at 72 weeks were -20.2% with tirzepatide and -13.7% with semaglutide. Both groups lost weight; tirzepatide produced the greater average loss.

I prefer this sort of direct encounter to comparing the most flattering number from each of two unrelated trials. It still answers a weight question. Semaglutide’s heart and kidney findings come from their own trials, with their own participants and outcomes.

Four subjects, different company

• GHK-Cu: skin and mixtures. A plasma peptide became a cosmetic ingredient; its strongest scalp comparison tested a mixture containing GHK.
• NAD+: blood and muscle. Supplement trials found blood changes, while a muscle experiment produced a more selective response.
• MOTS-c: muscle and risk. Mouse exercise results sit alongside a human dialysis study in which nobody received the peptide.
• STEP 1, SELECT, FLOW: semaglutide. Placebo and another medicine supply different comparisons.

NAD+ is a coenzyme involved in cellular energy use, rather than a peptide. Its place beside these peptides reflects the research questions they share, not a shared chemical identity.

The remaining questions

Some of the most useful findings here are selective: muscle insulin sensitivity improved while body composition and HbA1c stayed unchanged. Others leave a large gap: human NAD+ trials have shown limited efficacy overall, despite repeatable blood increases.

A selective muscle result wins my respect; the larger ambition still has work to do. The comparison register brings these particular experiments together; the reference shelf contains the papers themselves.