Amino acids
Glycine
Also known as: L-glycine, aminoacetic acid
The simplest amino acid — a building block of collagen and glutathione. Small oral sleep studies exist; IV beauty and anti-aging claims do not.
Medically reviewed by Akash Bhagat, DO, FACEP
What the evidence supports
| Use | Evidence |
|---|---|
| Sleep quality (oral glycine, small trials) | Limited |
| IV anti-aging, mood, or 'beauty' drips | Unproven |
Common side effects
- Nausea
- Soft stools
- Vein irritation
Who should be cautious or avoid this
- Kidney or liver disease
- Rare inherited glycine-metabolism disorders
What it is
Glycine is a nonessential amino acid your body makes and also gets from protein foods. It is a building block of collagen and of glutathione, and it acts as an inhibitory neurotransmitter in the spinal cord.
Why it’s used in IV therapy
Added to athletic, beauty, and “anti-aging” drips, and sold as a shot, for mood, skin, and performance.
What the evidence says
A few small trials of oral glycine at bedtime reported modest sleep improvements — limited evidence, not a drip protocol. Using glycine in an IV for skin, mood, or aging has no meaningful clinical support. Collagen and glutathione chemistry does not mean a few hundred milligrams in a bag will change your skin or “reverse” aging.
Side effects and cautions
Generally well tolerated. Skip extra amino-acid loads if you have significant kidney or liver disease. Related: taurine and the amino-acid blend.