SH-Oligopeptide-78 is a synthetic oligopeptide stabilized with a sulfhydryl group (the “SH” in the name) at the cysteine residue. The sulfhydryl group is a sulfur-hydrogen pair that gives the peptide affinity for damaged keratin sites, where similar sulfur chemistry is involved in the structural disulfide bonds that hold the hair fiber together.

The “78” is the INCI registry number, not a structural identifier — it distinguishes this particular sequence from other sulfhydryl oligopeptides.

Damaged hair has broken disulfide bonds and exposed cysteine sites in the keratin matrix. SH-Oligopeptide-78 is structured to:

1. Penetrate the cuticle into the cortex — the peptide is small enough to enter the fiber’s interior.
2. Bind at damage sites — the sulfhydryl group has chemical affinity for the cysteine residues exposed when disulfide bonds break.
3. Stabilize the local protein structure — once bound, the peptide acts as a localized reinforcement.
4. Support copper binding — sulfhydryl peptides chelate copper ions, which can otherwise catalyze oxidative damage.

The flagship dual peptide treatment. Applied to damp hair at pH 7.0–8.0 so the cuticle is open and accepts both peptides. Every wash, every day.

Biotinoyl Tripeptide-1 appears in four products across the system. SH-Oligopeptide-78 is concentrated in Atomic — the every-wash deposit where its sulfhydryl chemistry has the highest impact on chemically processed hair.