Across 695 first-hand reports, people mentioned a side effect 30 times (about 4 per 100 reports). The most common: vivid dreams, drowsiness, fatigue. User reports show what people notice — they can't tell you whether Glycine is safe for you.
“2 grams with 200mg magnesium before bed gives me crazy good sleep. Crazy vivid dreams.”
“Taking isolated glycine several days in a row makes me super groggy throughout the day. It puts me to sleep almost like a sedative.”
“I've been taking about 4.5 grams of glycine about an hour before bedtime to benefit sleep (the evidence on this seems relatively strong).”
“Someone on Reddit recommended 5000 mg of glycine a few hours before bed. Although not perfect, my score is now in the 70s and deep sleep is 45-60 min.”
“I take a lot of glycine...I take a couple of teaspoons of the powder every night and it helps me sleep without any sort of payback.”
“I tried using glycine as a sleep aid for a while and it did the opposite. Turns out it's stimulating for some people and sedating for others.”
Conclusion: In studies using high-throughput metabolomics, several blood amino acids appear to be consistently associated with the risk of developing type 2 diabetes.
Conclusion: Several plasma and serum metabolites, including amino acids, lipids, and carbohydrates, are associated with type 2 diabetes risk.