That said, most studies on collagen focus on its safety and effectiveness in the general populationnot specifically on breastfeeding women
In controlled studies, GHK-Cu has been shown to increase follicle size, extend the anagen (growth) phase, and improve overall hair density
This includes vegans and vegetarians, older adults, individuals with atrophic gastritis, pernicious anemia, gastrointestinal disorders, those who have had gastrointestinal surgery and people who take certain medications including, but not limited to, estrogen (HRT), and birth control pills
Nat Rev Microbiol 2021;19:14154 2
& Wistrand, P
(We also checked Prospector for sodium hyaluronate versions actually used in cosmetic products and found that the most common molecular weight was 1.5-1.8 million Da that absolutely counts as high molecular weight)