Glycine: What It Does and How It Helps Your Body

Glycine is a tiny amino acid with big jobs. You get it from meat, fish, dairy and gelatin, and your body uses it to build collagen, make glutathione (an antioxidant), and help nerves work properly. Unlike many health topics that get complicated fast, glycine is easy to understand and pretty safe for most people.

Here are the facts you actually need: glycine acts as an inhibitory neurotransmitter in the spinal cord and brainstem, helps form collagen for skin and joints, and is a building block for glutathione, a key antioxidant your cells use to remove toxins. It also sits at key places in metabolism and supports healthy digestion when you eat gelatin-rich foods or bone broth.

Benefits and common uses

People take glycine for a few practical reasons. If you struggle to fall asleep, 1–3 grams of glycine about 30–60 minutes before bed can help some people fall asleep faster and sleep more deeply. Athletes and older adults sometimes use glycine to support joints and skin because it’s essential for collagen production. There’s also interest in glycine for brain health: it acts as a co-agonist at NMDA receptors, which matters for memory and learning. Finally, because glycine contributes to glutathione, it can help with antioxidant support when combined with a healthy diet.

Food-first is smart: bone broth, gelatin desserts, chicken, fish and dairy are good sources. Most people get some glycine in their diet, but supplements are handy if you want a predictable dose for sleep or specific support.

How to take glycine safely

Typical supplement doses range from 1 to 3 grams daily. For sleep, many people take one 3-gram dose 30–60 minutes before bed. Start low—try 1 gram—and see how you feel. Glycine is generally well tolerated; the most common side effects are mild stomach upset or diarrhea at high doses. If you have kidney or liver disease, ask your doctor before adding glycine, since your medical team needs to confirm it’s safe for your specific situation.

Watch interactions: glycine can affect neurotransmitter systems, so check with a clinician if you take psychiatric meds or drugs that change brain chemistry. Pregnant or breastfeeding people should check with their provider before supplementing. If you prefer natural sources, adding bone broth, gelatin or collagen-rich foods will boost glycine without pills.

Choosing a supplement: pick a reputable brand that lists purity and has third-party testing if possible. Powder forms mix easily into water or tea; capsules work if you want convenience. Keep doses consistent and track effects for a week or two so you can judge benefits like improved sleep or less joint stiffness.

Glycine is simple, useful and low-risk for most people. If you want to try it for sleep, joint support, or antioxidant help, start with a small dose, use a trusted product, and check with your healthcare provider when in doubt.