Acetyl Hexapeptide-38 (Adifyline)_Dosage, benefits & legal status

Most cosmetic peptides claim to signal collagen or relax muscle. This one claims something different, and the claim is testable in principle and untested in practice.

1. 01
   The premise: grow the fat, not the collagen

   Facial fullness and breast volume are largely a matter of subcutaneous fat. The supplier's proposal is that this peptide promotes adipogenesis, meaning it encourages fat cells to differentiate and to store lipid, and that doing so topically adds visible volume. The named pathway is PGC-1-alpha, a regulator of mitochondrial biogenesis and metabolism, with the brochure reporting an increase of more than 61 percent in PGC-1-alpha expression and greater lipid accumulation in treated cells.
2. 02
   What the sequence is

   Ac-Ser-Val-Val-Val-Arg-Thr-NH2: six residues with the N-terminus acetylated and the C-terminus amidated. We checked that against the published formula and mass rather than taking it on trust. The arithmetic for the acetylated, amidated hexapeptide gives C30H56N10O9 at 700.84 daltons, matching the published C30H56N10O9 and 700.83 exactly.
3. 03
   The human data, and who produced it

   Two supplier studies. Cheeks: 22 women aged 50 to 60 applied a 2 percent cream twice daily for 14 days, with volume measured by fringe projection, giving a reported 12 percent increase. Breast: 22 women aged 25 to 40 applied 2 percent cream to one breast and placebo to the other twice daily for 56 days, with the result reported as a 30-fold improvement over placebo. Neither has been published in a peer-reviewed journal, and the chart values behind the 30-fold figure were not legible in the brochure we read.
4. 04
   Why a 30-fold claim deserves more scrutiny, not less

   A 30-fold difference against placebo would be remarkable for any topical. A ratio that large usually means the placebo change was close to zero, in which case the ratio is arithmetically unstable and tells you little: dividing a small number by a smaller one produces a big multiple without a big effect. That is why the absolute values matter and why their absence is the problem.
5. 05
   Four suppliers, four different mechanisms

   The same INCI is described by Lubrizol as an adipogenesis promoter through PGC-1-alpha; by a second supplier in terms that garble PGC-1-alpha into stimulating peroxisome proliferators; by a reagent company as an anti-irritant that lowers IL-8 in keratinocytes, citing a skin-barrier patent; and by another as a dermal collagen stimulant whose sole citation is a review of natural collagen peptides not about this molecule at all. European ingredient databases list it simply as skin conditioning. Those are not variations on a theme; they are four unrelated claims about one six-residue peptide.