Copper peptides are among the most studied cosmetic peptides. The literature suggests GHK-Cu may support collagen and elastin synthesis, skin remodeling, and recovery processes—mechanisms that align with improvements in firmness and texture over time. PMC+2PMC+2

Studies / Reviews:

• Regenerative & protective actions of GHK-Cu (review): https://pmc.ncbi.nlm.nih.gov/articles/PMC6073405/ PMC
  
• Using copper to improve skin well-being (review): https://pmc.ncbi.nlm.nih.gov/articles/PMC4556990/ PMC
  
• GHK-Cu in oxidative stress & regeneration (review): https://pmc.ncbi.nlm.nih.gov/articles/PMC3359723/ PMC
  

Topical niacinamide has clinical evidence supporting improvements in multiple visible markers of skin aging and tone. Trials and reviews report benefits including smoother texture, reduced appearance of wrinkles, and improvement in hyperpigmentation in some contexts. PubMed+3PubMed+3PMC+3

Studies / Reviews:

• Niacinamide reduces wrinkling/redness/yellowing (clinical study): https://pubmed.ncbi.nlm.nih.gov/18492135/ PubMed
  
• Niacinamide 4% for melasma (RCT): https://pmc.ncbi.nlm.nih.gov/articles/PMC3142702/ PMC
  
• Mechanistic basis + clinical evidence for niacinamide (review): https://pmc.ncbi.nlm.nih.gov/articles/PMC8389214/ PMC
  
• Effect on reducing cutaneous hyperpigmentation (clinical): https://pubmed.ncbi.nlm.nih.gov/12100180/ PubMed
  

Hyaluronic acid is strongly supported in the literature as a non-invasive way to improve hydration, plumpness, and the appearance of fine lines—primarily via water retention and barrier support. PMC+2PMC+2

Studies / Reviews:

• Benefits of topical HA for skin quality (review): https://pmc.ncbi.nlm.nih.gov/articles/PMC10078143/ PMC
  
• Topical HA serum efficacy (clinical study): https://pmc.ncbi.nlm.nih.gov/articles/PMC8322246/ PMC
  
• PubMed record (review): https://pubmed.ncbi.nlm.nih.gov/36200921/

Palmitoylated peptides have published evidence and clinical reporting suggesting measurable improvements in wrinkle metrics and skin roughness/texture in some studies. MDPI+1

Studies / Reviews:

• Topical peptide treatments with anti-aging results (review + clinical summaries): https://www.mdpi.com/2079-9284/4/2/16 MDPI
  
• Anti-aging peptides review (includes Matrixyl 3000 performance summaries): https://www.sciencedirect.com/science/article/pii/S1773224723009395

Topical growth factor products are studied in aesthetics, with reviews suggesting modest improvements in texture, fine lines, and overall appearance in some trials. The evidence is mixed by formulation and delivery method, so expectations should be realistic. PMC+3PubMed+3PMC+3

Studies / Reviews:

• Topical growth factor preparations for facial rejuvenation (review): https://pubmed.ncbi.nlm.nih.gov/37222303/ PubMed
  
• EGF in aesthetics & regenerative applications (review): https://pmc.ncbi.nlm.nih.gov/articles/PMC8423211/ PMC
  
• EGF in dermatological practice (review): https://pmc.ncbi.nlm.nih.gov/articles/PMC10333026/ PMC
  
• Microneedling ± growth factor RCT context: https://pmc.ncbi.nlm.nih.gov/articles/PMC7716740/

Polynucleotides (including PDRN-related materials) have growing evidence in regenerative/aesthetic contexts, including wound healing, barrier improvement, and skin texture support—more robust in medical/aesthetic settings, and increasingly explored in topical/cosmetic contexts. PMC+2PMC+2

Studies / Reviews:

• Pharmacological activity & clinical use of PDRN (review): https://pmc.ncbi.nlm.nih.gov/articles/PMC5405115/ PMC
  
• Polynucleotides in aesthetic medicine (review): https://pmc.ncbi.nlm.nih.gov/articles/PMC11311621/ PMC
  
• PDRN and skin regeneration/barrier improvement (study): https://pmc.ncbi.nlm.nih.gov/articles/PMC10649580/

Ergothioneine is a well-characterized antioxidant studied for protective effects in oxidative stress and photoaging models; human data exists in related contexts, and mechanistic work supports its role as a cytoprotective antioxidant. PMC+2PMC+2

Studies / Reviews:

• Ergothioneine anti-aging activity in UVA models: https://pmc.ncbi.nlm.nih.gov/articles/PMC7038158/ PMC
  
• Mechanisms & safety overview: https://pmc.ncbi.nlm.nih.gov/articles/PMC9967237/ PMC
  
• Ergothioneine “stress vitamin” review: https://pmc.ncbi.nlm.nih.gov/articles/PMC9221166/ PMC
  

Curcumin is widely studied for antioxidant and anti-inflammatory effects relevant to skin stress and photoaging pathways; evidence includes mechanistic and translational research, with topical use often discussed in the context of irritation tolerance and formulation stability. PMC+1

Studies / Reviews:

• Curcumin in skin disorders (review): https://pmc.ncbi.nlm.nih.gov/articles/PMC6770633/ PMC
  
• Curcumin as a potential anti-photoaging agent (review): https://pmc.ncbi.nlm.nih.gov/articles/PMC12090238/

Rose extracts have published evidence for anti-inflammatory and antioxidant activity relevant to skin comfort and irritation pathways, particularly in UV-stress contexts. PMC+1

Studies / Reviews:

• Skin anti-inflammatory activity of rose petal extract: https://pmc.ncbi.nlm.nih.gov/articles/PMC6261181/ PMC
  
• Rose oil and UVB oxidative damage (study context): https://pmc.ncbi.nlm.nih.gov/articles/PMC10515598/ PMC
  

“Plant stem cell” actives in cosmetics are discussed primarily in terms of antioxidant/anti-inflammatory pathways and skin-supporting activity; the overall evidence base tends to be broader at the mechanistic level, and results depend heavily on the specific extract/vehicle used. PMC+2Wiley Online Library+2

Studies / Reviews:

• Plant stem cells in cosmetics (review): https://pmc.ncbi.nlm.nih.gov/articles/PMC5674215/ PMC
  
• Apple stem cell effects in UVB skin damage model: https://onlinelibrary.wiley.com/doi/10.1155/2022/2417766 Wiley Online Library
  
• Apple-derived vesicles & collagen markers (mechanistic): https://pmc.ncbi.nlm.nih.gov/articles/PMC9776931/ PMC