Glycine vs Magnesium L-Threonate

Sleep vs Sleep · evidence-backed comparison

Quick take
  • Glycine has the stronger evidence base (moderate (some rcts)).
  • Magnesium L-Threonate has the broader effect profile across the 9 effect categories.
  • Glycine is cheaper per serving ($0.10 vs $1.10).

Side-by-side traits

TraitGlycineMagnesium L-Threonate
Category
SleepSleep
Active compound
GlycineMagnesium L-threonate
Form available
Powder, CapsuleCapsule, Powder
Source
syntheticsynthetic
Typical dose
3 g before bed1.5–2 g (≈144 mg elemental Mg)
Dose range
3–5 g1500–2000 mg
Loading protocol
Best taken with
water, 30 min before bedevening
Best time of day
eveningevening
Bioavailability
How efficiently the body absorbs and utilizes the compound.
Very High (5/5)Very High (5/5)
Onset time
Acute: 30–60 minCumulative: 4–12 weeks
Half-life
~1 hour
Evidence level
Quality and quantity of human research.
Moderate (some RCTs)Limited (small studies)
Overall effect
Subjective effect magnitude.
Low (2/5)Moderate (3/5)
Muscle / strength
Low (2/5)Very Low (1/5)
Physical energy
Very Low (1/5)Very Low (1/5)
Focus / cognition
Low (2/5)High (4/5)
Mood / stress
Moderate (3/5)Moderate (3/5)
Sleep quality
High (4/5)High (4/5)
Immunity
Very Low (1/5)Very Low (1/5)
Recovery
Post-exercise recovery support.
Low (2/5)Very Low (1/5)
Longevity / healthspan
Moderate (3/5)Moderate (3/5)
Safety rating
5 = exceptionally well-tolerated; 1 = significant risk profile.
Very High (5/5)Very High (5/5)
Price per serving
Approximate USD per typical daily dose.
$0.10$1.10
Vegan friendly
YesYes
Gluten free
YesYes
3rd-party tested
YesYes

About Glycine

Sweet-tasting amino that lowers core body temperature for deeper sleep. Cheap, well-tolerated, and especially useful with magnesium glycinate.

Active compound: Glycine
Forms: Powder, Capsule
Onset: Acute: 30–60 min
sleep-qualitydeep-sleepamino-acidthermal-regulation

About Magnesium L-Threonate

Only magnesium form proven to cross the blood-brain barrier in animals. Marketed for cognitive aging and sleep, but premium-priced.

Active compound: Magnesium L-threonate
Forms: Capsule, Powder
Onset: Cumulative: 4–12 weeks
brainsleepmemoryblood-brain-barrier

Glycine safety

Common side effects:

  • Generally none

Avoid if:

  • Clozapine therapy

Drug interactions:

  • Clozapine

Magnesium L-Threonate safety

Common side effects:

  • Drowsiness
  • Headache (rare)

Avoid if:

  • Severe kidney disease

Drug interactions:

  • Bisphosphonates

Common uses

  • Deep sleep
  • Sleep quality
  • Collagen synthesis

Stacks well with: Magnesium Glycinate, Melatonin

Common uses

  • Cognitive aging
  • Deep sleep
  • Memory

Stacks well with: Zinc, Vitamin D3

Medical disclaimer

SupplementDuel is for educational purposes only and is not medical advice. Consult a physician before starting, stopping, or combining supplements — especially if you are pregnant, breastfeeding, take prescription medication, or have a chronic condition.