Quick answerWeak evidence
Leave-on peptide scalp serums are low-risk. Human evidence that they thicken hair is limited. Worth a 3-month try if you want a gentle option; not a treatment for medical hair loss.
!
Injectable versions are not covered here. We only cover topical and oral products sold legally as cosmetics or food supplements. Injectable or “research” peptides are not approved for personal use and carry real risks.
What they are
Water-light serums with peptide blends applied to the scalp and left on. Marketing often promises denser-looking hair. Lab data is interesting; robust human trials are scarce.
Our pick
FAQ
Morning or night?
Either. Apply to a clean scalp and leave on; do not rinse.
Can I use minoxidil with it?
Ask a pharmacist or dermatologist. Do not mix actives without advice.