GHK-Cu is administered as a daily subcutaneous injection with a 30-day cycle followed by a 30-day break
FIGURE 2 The accumulation of methylmalonic acid (MMA) and Hcy because of these disruptions leads to oxidative damage and impaired methylation

Fatigue accompanied by other concerning symptoms including: Persistent dizziness, lightheadedness, or fainting Rapid or irregular heartbeat Shortness of breath or chest pain Severe or unrelenting nausea and vomiting Inability to keep down food or fluids for more than 24 hours Dark urine, markedly reduced urination, or swelling (signs of dehydration or kidney problems) Yellowing of skin or eyes Severe abdominal pain Mood changes, depression, or difficulty concentrating Signs of potential complications require immediate attention: Stop the medication and seek urgent medical care if you experience severe abdominal pain (especially radiating to the back) which could suggest pancreatitis Stop the medication and seek urgent care if you develop symptoms of severe allergic reaction (rash, itching, swelling, severe dizziness, trouble breathing) Symptoms suggesting gallbladder disease (right upper abdominal pain, especially after eating) Hypoglycemia in patients taking diabetes medications (shakiness, sweating, confusion) Inability to meet nutritional needs despite best efforts, or unintentional weight loss exceeding recommended rates (generally more than 1-2 pounds per week after the initial period)

For people with absorption issues (and most adults over 50 have at least some), oral B12 simply doesnt deliver enough cobalamin to make a felt difference
The short, clear answer is this: Glutathione should be taken for a minimum of 3 months, with an ideal duration of 36 months, depending on your skin goals, dosage, and individual response
A 0.05% BAC legal limit is most common and found in Western European countries