Yes — glycine is abundant in collagen-rich foods, and 1.2 g is not a demanding target.
Watch gelatine and collagen prices →Can you get it from food?
Glycine makes up roughly a third of the amino acids in collagen, so anything collagen-rich delivers it in quantity: slow-cooked cuts, skin-on chicken, bone broth, gelatine. Gelatine is about a quarter glycine by weight, so a standard sachet gets you into gram territory on its own. Meat, fish, dairy and legumes all contribute. Reaching the 1.2 g in the Longevity Mix is realistic through diet; reaching the 3 g used in the trials is harder but not absurd if collagen or gelatine is a regular part of what you eat.
| Food | To match the dose | |
|---|---|---|
| Gelatine / collagen powder | ~5 g for 1.2 g | Roughly 25% glycine by weight — the most direct food route |
| Bone broth | Varies widely | Depends entirely on how it was made and how long |
| Slow-cooked collagen-rich cuts | A normal serve contributes meaningfully | Osso buco, pork belly, chicken with skin |
| Meat, fish, dairy, legumes | Contributes across the day | Lower concentration, but constant |
Legumes contribute, but the densest sources are collagen-based and therefore animal-derived. Vegetarians will find 3 g harder than omnivores.
What the research actually shows
The most-cited human work is a small trial in which participants with sleep complaints took 3 g of glycine an hour before bed for four consecutive nights. It used polysomnography rather than questionnaires alone, and reported shortened latency to sleep onset and to slow-wave sleep without altering sleep architecture, alongside improvements in subjective sleep quality and next-day sleepiness. Note the scale: fifteen participants. There is no large pooled meta-analysis of glycine for sleep in the way there is for creatine or theanine — the evidence base is individual small trials, and it should be read that way.
On certainty: Two things worth holding together. First, the trials used 3 g and the Longevity Mix carries 1.2 g — well under half, with no obvious basis for assuming the effect scales down proportionally. Second, fifteen people is a pilot, not a settled finding. Anyone presenting glycine-for-sleep as established is overstating what has actually been shown.
The studies referenced
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Glycine ingestion improves subjective sleep quality in human volunteers, correlating with polysomnographic changes
3 g glycine before bed shortened polysomnographic latency to sleep onset and slow-wave sleep without changing sleep architecture; improved subjective quality and reduced daytime sleepiness. -
Dietary protocols to promote and improve restful sleep: a narrative review
Places glycine among dietary approaches to sleep and reviews the supporting evidence base. -
Collagen peptide supplementation before bedtime reduces sleep fragmentation and improves cognitive function in physically active males with sleep complaints
Relevant because collagen is glycine-rich — an indirect route to the same amino acid.