The Glow Journal: peptides for skin, hair & nails

• Argireline (Acetyl Hexapeptide-8): Is It Really "Botox in a Jar"? — Argireline is the most famous "Botox-like" peptide. We review every peer-reviewed trial, including the positive results and the independent study that found no difference, plus SNAP-8, Leuphasyl, safe concentrations and how to use it.
• The Best Peptides for Skin: A Complete, Evidence-Based Guide — Which peptides are actually worth looking for in skincare? We break down signal, neurotransmitter, carrier and enzyme-inhibitor peptides, what the clinical studies show, and how to use them in a routine.
• How to Layer Peptides with Vitamin C, Niacinamide, Retinol and Acids — The right order to apply peptides, and what you can (and can't) mix them with. A clear, evidence-checked guide to layering peptides with vitamin C, niacinamide, retinol, AHAs/BHAs and copper peptides, with sample AM/PM routines.
• Matrixyl vs. Matrixyl 3000: Palmitoyl Pentapeptide-4 and the Signal Peptides Explained — Matrixyl (palmitoyl pentapeptide-4) has one of the best clinical trials of any cosmetic peptide. Here's how it compares with Matrixyl 3000, Matrixyl synthe'6, hexapeptide-9 and other signal peptides, what the research shows, and how to use them.
• The Cosmetic Peptide Encyclopedia: Every Common Skincare Peptide, A to Z — An A–Z reference to cosmetic peptides in skincare, hair care and eye care - INCI names, trade names, what each is used for, and an honest rating of the published evidence, with sources.
• Peptides for Acne-Prone Skin: What Antimicrobial and Cosmetic Peptides Can (and Can't) Do — Can peptides help acne? We explain the antimicrobial peptides your skin makes, the peptide acne trials (including one that never published results), copper peptides for acne scars, and how to build a peptide routine around proven acne treatments.
• Peptides for Body Skin: Crepey Arms, Stretch Marks, Rough Skin and What Actually Works — Do peptide body lotions work? An evidence-based look at crepey skin, stretch marks, keratosis pilaris, dry skin, cellulite and collagen supplements, plus what to put in your body-care routine.
• Peptides for Lips: Do Peptide Lip Treatments Plump, Smooth and Hydrate? — Why lips get dry, thin and lined, what peptide lip treatments and "plumpers" can really do, which claims have no evidence, and a simple lip-care routine that works.
• Peptides for the Neck and Décolletage: Neck Lines, Crepey Skin and What Neck Creams Can Do — Why the neck and chest show age, what's behind "tech neck" and necklace lines, what clinical studies of neck creams really found (including placebo results), and a simple neck-care routine with peptides, retinol and sunscreen.
• Peptides for Sensitive Skin and Redness: Gentle Actives That Support Your Barrier — Are peptides good for sensitive skin? We look at soothing peptides like palmitoyl tripeptide-8 and acetyl dipeptide-1 cetyl ester, the skin's own antimicrobial peptides, and how to build a calm, barrier-friendly routine.
• Peptides for Under-Eye Bags, Puffiness and Dark Circles: What Actually Helps? — Why you get dark circles and under-eye bags, which peptide and caffeine eye creams have real evidence, and when an eye cream can or can't help. Covers acetyl tetrapeptide-5, Eyeliss, Haloxyl and caffeine.
• Peptides for Glowing Skin: How to Build a Routine for Radiance — What actually makes skin look "glowy", and where peptides fit in. A step-by-step routine with peptides, niacinamide, hydrators and gentle exfoliation, backed by the research.
• Peptides for Hair: What the Research Says About Hair Growth, Thinning and Hair Loss — Copper peptides, biotinoyl tripeptide-1, acetyl tetrapeptide-3, lash peptides. We review the real evidence for peptides in hair and scalp care, what results are realistic, and when to see a dermatologist.
• Peptides for Nails: Can They Fix Brittle, Peeling Nails? — Do collagen peptides strengthen nails? What about peptide nail serums? A clear look at the research on peptides for brittle, peeling and slow-growing nails, plus a nail-care routine that works.
• Copper Peptides (GHK-Cu) for Skin: Benefits, Research and How to Use Them — What copper peptides are, what GHK-Cu does for skin according to the research, how strong the evidence really is, and how to use a copper peptide serum with vitamin C, retinol and acids.
• Peptides vs. Retinol: Which Is Better for Your Skin (and Can You Use Both)? — Retinol has decades of research; peptides are gentler. We compare how each works, what the studies show (including a head-to-head trial vs. prescription tretinoin), and how to combine them in one routine.