Many people take collagen for cosmetic reasons: skin, hair, nails, or joints. But there’s a less discussed benefit that can be just as interesting: its relationship with glycine, an amino acid involved in detoxification pathways and, in some people, associated with deeper sleep.
In this article you’ll see why collagen is a different kind of protein, what changes with age, and how to use it practically if your goal is to support rest and recovery.
What collagen is (and why many diets are low in it)
Roughly 30% of the body’s protein is collagen. It forms part of the structural “glue”: tendons, ligaments, cartilage, fascia, skin, and a meaningful portion of bone. Historically, many cultures ate more “nose to tail”: broths, cartilage, skin, gelatin, and slow-cooked dishes with connective tissue.
Modern diets often favor tender, lean cuts (chicken breast, very trimmed steaks). In some estimates, only 1–3% of dietary protein comes from collagen, far below what the body uses to build connective tissue.
Aging: less collagen, more fragility
With age, total collagen and connective tissue quality decline. This can show up as:
- More wrinkles and sagging
- Slower recovery
- Joint discomfort
- A general sense of stiffness
It’s not only aesthetics: it’s structure and resilience.
Glycine: the bridge to sleep
Collagen is rich in glycine. Glycine is involved in:
- Glutathione synthesis, one of the liver’s main antioxidants
- Detoxification processes
- Support of the intestinal lining (barrier function)
- Sleep regulation, including deeper sleep in some people
If your diet is low in collagen, your glycine intake may be low too. And while sleep depends on many factors, adding glycine via collagen can be a helpful push for some.
“Taking collagen” doesn’t mean it goes straight to your skin
One important point: when you digest collagen, most of it breaks down into amino acids (like any protein). However, a small fraction can remain as peptides, which may act as signaling molecules. That signaling is one hypothesis for why collagen can support tissue repair beyond “just protein” in certain people.
The practical translation: don’t expect overnight changes. Think weeks, and combine it with habits that support tissue synthesis (adequate total protein, vitamin C, sleep, and strength training).
How to use it if your goal is better sleep
Option A: collagen at night
- 10–20 G of hydrolyzed collagen in a hot or cold drink
- 30–60 Minutes before bed
Option B: collagen-rich foods
- Bone broth (homemade or good-quality)
- Sugar-free gelatin
- Connective-tissue cuts (slow cooking)
Option C: glycine (with professional guidance)
Some people use isolated glycine. If you’re interested, ask first, especially if you have medical conditions or take medications.
What to look for in a supplement (so you don’t waste money)
If you choose collagen powder, look for:
- Hydrolyzed collagen (mixes easily and is often better tolerated)
- A simple ingredient list, without unnecessary added sugars
- A clear source (bovine, marine, etc.) and basic quality controls
You don’t need “premium” blends with twenty extras. Consistency usually matters more.
When you might notice changes
Think 4–8 weeks, not days. Evaluate with concrete signals:
- Falling asleep faster or waking less
- Less morning stiffness when you strength train
- More stable digestion (as long as your overall diet supports it)
If your goal is “perfect skin” without good sleep or sun protection, you likely won’t see much change.
Common myths
- “Collagen goes straight to wrinkles”: the body digests it and allocates it based on needs; context matters most
- “More is always better”: higher dose doesn’t compensate for poor tolerance; prioritize regularity
- “It replaces protein”: collagen doesn’t replace complete protein; use it as a complement
Practical tips to boost the effect
- Ensure enough total daily protein (not only collagen)
- Get vitamin C during the day (fruit, peppers, broccoli): supports collagen synthesis
- Strength train 2–3 times per week: tissue adapts to demand
- Keep basic sleep hygiene: morning light, consistent schedule, less late alcohol
Make it easier to stick with
Collagen is only useful if you actually take it. Many people find it easiest to add to:
- Warm tea or decaf coffee in the evening
- A simple yogurt bowl
- A smoothie when you’re not close to bedtime
Choose a format you can repeat without thinking.
Precautions
Collagen is usually well tolerated, but it can cause digestive discomfort in some people. If you have kidney or liver disease, significant digestive issues, or you’re pregnant/breastfeeding, ask before using it.
Conclusion
Collagen isn’t only “beauty.” Through its glycine content and possible peptide signaling, it can support recovery and, for some people, improve sleep quality. Use it as part of a bigger strategy: adequate protein, strength training, vitamin C, and sleep habits.
Knowledge offered by Dr. Eric Berg