On average, around 70% of people see improvements from caffeine, which is fairly high for a supplement
Anti-Ageing and Skin Remodelling: Clinical studies have shown that topical GHK-Cu creams can increase collagen production, improve skin elasticity, reduce fine lines and wrinkles, increase skin thickness, and improve overall skin appearance
5.2.6 Integrates relevant information with previous learning, experience, professional knowledge, and current practice models
Dietary supplement use and documentation in a breast cancer survivorship clinic
Its found in some fruits and vegetables as well as human breast milk
Bottom line: Given the current lack of research, its typically best to play it safe and avoid taking semaglutide while breastfeeding