Iodine (Potassium Iodide) vs Magnesium Glycinate

Mineral vs Sleep · evidence-backed comparison

Quick take
  • Iodine (Potassium Iodide) has the stronger evidence base (strong (multiple rcts / meta-analyses)).
  • Magnesium Glycinate has the broader effect profile across the 9 effect categories.
  • Iodine (Potassium Iodide) is cheaper per serving ($0.05 vs $0.25).
  • Magnesium Glycinate has a slightly cleaner safety profile.

Side-by-side traits

TraitIodine (Potassium Iodide)Magnesium Glycinate
Category
MineralSleep
Active compound
Potassium iodideMagnesium chelated to glycine
Form available
Capsule, Tablet, LiquidCapsule, Powder, Tablet
Source
mineralsynthetic
Typical dose
150 mcg daily200–400 mg elemental Mg
Dose range
150–300 mcg200–400 mg
Loading protocol
Best taken with
with foodevening, with water
Best time of day
morningevening
Bioavailability
How efficiently the body absorbs and utilizes the compound.
Very High (5/5)Very High (5/5)
Onset time
Cumulative: 2–8 weeksAcute: 1–3 hours
Half-life
~28 hours (Mg)
Evidence level
Quality and quantity of human research.
Strong (multiple RCTs / meta-analyses)Moderate (some RCTs)
Overall effect
Subjective effect magnitude.
Low (2/5)Moderate (3/5)
Muscle / strength
Very Low (1/5)Moderate (3/5)
Physical energy
Low (2/5)Low (2/5)
Focus / cognition
Very Low (1/5)Low (2/5)
Mood / stress
Low (2/5)Moderate (3/5)
Sleep quality
Very Low (1/5)High (4/5)
Immunity
Low (2/5)Low (2/5)
Recovery
Post-exercise recovery support.
Very Low (1/5)Moderate (3/5)
Longevity / healthspan
Low (2/5)High (4/5)
Safety rating
5 = exceptionally well-tolerated; 1 = significant risk profile.
Moderate (3/5)Very High (5/5)
Price per serving
Approximate USD per typical daily dose.
$0.05$0.25
Vegan friendly
YesYes
Gluten free
YesYes
3rd-party tested
YesYes

About Iodine (Potassium Iodide)

Essential for thyroid hormone synthesis. Iodized salt usually covers needs; supplement only if confirmed deficient.

Active compound: Potassium iodide
Forms: Capsule, Tablet, Liquid
Onset: Cumulative: 2–8 weeks
thyroiddeficiency-correctionpregnancy

About Magnesium Glycinate

The best-tolerated, best-absorbed magnesium form for sleep and stress. Doesn't cause loose stools like citrate.

Active compound: Magnesium chelated to glycine
Forms: Capsule, Powder, Tablet
Onset: Acute: 1–3 hours
sleepstressmuscle-relaxationnon-laxative

Iodine (Potassium Iodide) safety

Common side effects:

  • Acne
  • Hyperthyroidism (high doses)
  • Goitre (paradox)

Avoid if:

  • Hyperthyroid
  • Graves' disease
  • Hashimoto's (caution)

Drug interactions:

  • Lithium
  • Anti-thyroid drugs

Magnesium Glycinate safety

Common side effects:

  • Mild laxative effect (rare)
  • Drowsiness

Avoid if:

  • Severe kidney disease

Drug interactions:

  • Bisphosphonates
  • Antibiotics (timing)

Common uses

  • Thyroid support
  • Pregnancy
  • Iodine deficiency

Stacks well with: Selenium (Selenomethionine)

Common uses

  • Sleep quality
  • Anxiety
  • Muscle cramps
  • RLS

Stacks well with: Zinc, Vitamin D3, Melatonin

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.