How collagen could help you sleep better
Scarlett Gray
BNutrDiet (Hons), APD, SDA
Reviewed by Scarlett Gray · About Scarlett
Accredited Practising Dietitian with Dietitians Australia (APD200526). Accredited Sports Dietitian and Credentialled Eating Disorder Clinician. First Class Honours in Nutrition and Dietetics from the University of Newcastle.
Scarlett Gray
BNutrDiet (Hons), APD, SDA
Accredited Practising Dietitian with Dietitians Australia (APD200526). Accredited Sports Dietitian and Credentialled Eating Disorder Clinician. First Class Honours in Nutrition and Dietetics from the University of Newcastle.
Struggling to sleep? Here's what the science says about collagen and rest
Getting around eight hours a night dramatically improves our overall mental and physical wellbeing, but many adults regularly experience poor sleep. If you've been looking into what might help — beyond the obvious basics of sleep hygiene — one nutritional factor that has attracted genuine scientific interest is glycine, an amino acid found in high concentrations in collagen protein. This article looks honestly at what the research shows, what it doesn't show yet, and where collagen fits in.
What is glycine — and why does it matter for sleep?
Glycine is one of the amino acids that make up the proteins in our bodies. It plays roles in cardiovascular, cognitive and metabolic health, and works as a fundamental building block for protein synthesis across many tissues.
What's interesting about collagen from a sleep perspective is that collagen contains an unusually high proportion of glycine — approximately 20-33% of collagen's amino acid content, which is more glycine by proportion than almost any other dietary protein. A 10g serving of marine collagen therefore provides roughly 2-3g of glycine, which is close to the dose used in the published clinical research on glycine and sleep.
Kollo Premium Liquid Marine Collagen delivers 10,000mg (10g) of Naticol® marine collagen per daily sachet, alongside vitamin C, a B vitamin complex (B1, B5, B6, B12) and l-lysine. B12 in the formula contributes to the reduction of tiredness and fatigue — an authorised health claim under UK food law, and a relevant piece of the puzzle for daytime energy alongside anything you're doing for the night side.
What the research shows on glycine and sleep
Several small clinical studies on isolated glycine supplementation (typically around 3g taken shortly before bed) have reported improvements in subjective sleep quality, easier sleep onset, and reduced daytime tiredness the following day. Two of the more commonly cited papers are Bannai & Kawai (PubMed 21647662) and a related 2012 clinical trial on glycine and sleep (PubMed 22293292).
The proposed mechanism: glycine appears to reduce core body temperature by increasing blood flow to the extremities. Since sleep onset is associated with a drop in core body temperature, this may help you fall asleep more easily. Some of the research also suggests that when the body is well-supplied with glycine, sleep quality may improve — with easier transition into the deeper, slow-wave stages of sleep that are the most restorative.
Insomnia and daytime tiredness
For people who experience insomnia symptoms or persistent daytime tiredness, the evidence on glycine is encouraging. The published trials suggest that the amino acid may support sleep quality and reduce feelings of daytime fatigue. If you experience persistent sleep issues, though, a conversation with your GP is the right first step — sleep is important enough that it deserves proper assessment rather than a supplement-only approach.
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Shop Liquid Collagen →Practical takeaways
- Sleep hygiene comes first — a cool, dark room, consistent bedtime, and limiting screens before bed are the foundation. No supplement compensates for poor sleep hygiene
- Consistency matters — take your collagen at the same time each day; some people find evening works well given the glycine content, but consistency matters more than timing
- Persistent issues deserve a GP visit — if you're not sleeping well most nights, book an appointment. Sleep affects almost every part of health
- Fish allergy — marine collagen isn't suitable for anyone with a fish allergy
Frequently Asked Questions
Can collagen help me sleep?
Collagen is rich in glycine, an amino acid that has been studied for its effects on sleep quality. Small clinical studies on isolated glycine supplementation have reported improvements in subjective sleep quality and daytime tiredness. However, the sleep research has been conducted on isolated glycine — not on collagen — so we don't yet have direct clinical evidence that collagen supplements improve sleep. It's a plausible mechanism worth being aware of, but not a guaranteed result.
How much glycine is in a serving of Kollo?
Collagen contains an unusually high proportion of glycine — approximately 20-33% of its amino acid content. A 10g daily serving of Kollo Premium Liquid Marine Collagen therefore provides roughly 2-3g of glycine, which is close to the dose used in the published clinical research on glycine and sleep.
When should I take collagen for sleep support?
The sleep studies on isolated glycine typically dosed shortly before bed. That said, no direct research has been conducted on collagen for sleep, so we can't say with confidence that evening dosing produces different results to morning dosing. What we do know is that consistency matters more than timing — take it at whichever time you'll actually remember every day.
Should I take an isolated glycine supplement instead?
If sleep support is your only goal, an isolated glycine supplement may be a more targeted choice — that's what the sleep research has actually tested. Collagen provides glycine alongside its other benefits (skin, hair, nails, joints), which is why many people take it as a broader daily supplement. Either way, if you have persistent sleep issues, speak with your GP first.
Is glycine safe?
Glycine is a naturally occurring amino acid found in most protein-containing foods. It is generally well tolerated at typical supplement doses. If you have any existing medical condition or take prescription medication, speak with your GP before starting a new supplement.
For the complete picture on liquid marine collagen — dose, sources, research and how to choose the right supplement — read our complete guide to liquid marine collagen.
Kollo Health was co-founded by Jenni Falconer — TV presenter, Smooth Radio breakfast host, ten-time London Marathon runner and host of the RunPod podcast. Read her story and why she created Kollo.
