Glutathione levels can drop due to oxidative stress - the imbalance of free radicals and antioxidants in your body, and low vitamin E and alpha-lipoic acid intake

While glutathione supplements are broadly suitable for almost anyone who wants to increase their body's capacity to combat oxidative stress, they can best serve individuals who wish to prevent, delay, or alleviate specific chronic health conditions associated with glutathione depletion:15 Neurodegenerative disorders such as Alzheimer's and Parkinson's Respiratory diseases like asthma and COPD Cardiovascular diseases like hypertension and high cholesterol Age-related diseases like cataracts, macular degeneration, and hearing impairment Immune diseases like HIV and AIDS Liver disease Cystic fibrosis Additionally, because the goal is to reduce oxidative stress, people who are regularly exposed to ROS-generating compounds (e.g., smoke, alcohol, and sunlight)23 might consider adding glutathione to their supplement rotation, at least to help counter the effects of oxidative stressors

Because GHK-Cu stimulates the skin's own collagen-producing machinery rather than temporarily plumping the surface, the firmness improvement is structural it's still there months later, not gone the moment a filler effect wears off
[4] The feedback loop model proposes: collagen degrades with age, releasing GHK fragments
Because the peptide occurs naturally in human plasma (at roughly 200 ng/mL in young adults, declining to approximately 80 ng/mL by age 60), topical supplementation essentially restores youthful local concentrations in treated skin