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Topical cosmetic only. Matrixyl (palmitoyl pentapeptide-4 / pal-KTTKS, or the Matrixyl 3000 blend of palmitoyl tripeptide-1 + palmitoyl tetrapeptide-7) is used at very low concentrations in leave-on serums and creams — clinical benefit was shown at as little as 3 ppm pal-KTTKS, and consumer products commonly list 3-10% of the branded blend. Applied to the target area once or twice daily. There is no oral, injectable, or systemic dose — it is not ingested.

Any time

Leave-on topical cosmetic (serum or cream) containing palmitoyl pentapeptide-4 or the Matrixyl 3000 blend

Topical cosmetic only. OTC retinol is formulated roughly 0.1-1% in leave-on serums or creams and applied to clean, dry facial skin at night, starting 2-3 nights per week and building to nightly as tolerated. There is no oral, injectable, or systemic dose — this is not ingested. Higher concentrations work somewhat better but irritate more; pair with a moisturizer and a morning sunscreen. This library does not provide an ingestion protocol.

Evening

Leave-on topical serum or cream (0.1-1% retinol)

• For topical (skin) use only — not for ingestion, not for injection
• Known allergy or sensitivity to the peptide or formulation excipients
• Application to broken, irritated, or compromised skin until healed

• Other topical actives (retinoids, acids)

• For topical (skin) use only — not for ingestion, not for injection
• Pregnancy and breastfeeding — generally advised to avoid topical retinoids as a precaution
• Active eczema, rosacea flares, or broken/irritated/sunburned skin until healed

• Strong leave-on exfoliating actives (AHAs/BHAs, benzoyl peroxide)
• Other retinoids (prescription tretinoin, tazarotene, adapalene)