Magnesium
The single most useful mineral supplement for most people. Calms the nervous system, improves sleep, relaxes muscles, and underpins 300+ enzymatic reactions.
Multiple RCTs support magnesium for sleep onset, anxiety reduction, muscle cramps, and migraine prevention. The mechanism evidence (GABA modulation, NMDA antagonism, HPA-axis regulation) is robust. Effects typically felt within 3–7 days for sleep / calm, 1–2 weeks for anxiety, 4–6 weeks for full mineral repletion.
Magnesium is an essential mineral the body uses in hundreds of biochemical reactions — energy production, DNA synthesis, muscle contraction, nerve signalling, blood-sugar regulation, and the conversion of vitamin D to its active form. A large share of adults don't get enough from diet (estimates range 30–60% below the RDA), and the modern stressors that deplete it — alcohol, sugar, chronic stress, intense exercise, certain medications — are widespread. Of all the supplements on this list, this is the one most people benefit from most immediately.
- Form
- Glycinate (best general-purpose — calming, well-absorbed, doesn't cause loose stools). L-Threonate for cognitive / brain-targeted use (the only form that meaningfully crosses the blood-brain barrier). Citrate if you also want gentle bowel motility. Avoid oxide — cheap but poorly absorbed.
- Dose
- 200–400 mg elemental magnesium per day. Threonate is dosed by total compound weight (2 g delivers ~144 mg elemental). Start low (200 mg) and titrate up if needed — too much causes loose stools.
- Timing
- Evening, 30–60 min before bed for the calming / sleep effect. Threonate works AM too if cognition is the goal. With or without food. Citrate on an empty stomach if using for motility.
- Schedule
- Daily, ongoing. No cycling needed — magnesium is a sustained-replacement supplement, not a pulsed intervention.
- Side effects
- Loose stools at higher doses — citrate and oxide cause this most readily, glycinate least. If you get diarrhoea, switch form or drop the dose. Very high doses can cause low blood pressure or drowsiness.
- Interactions
- Reduces absorption of tetracycline and fluoroquinolone antibiotics, bisphosphonates, and levothyroxine — separate by at least 2 hours. Can enhance the effect of muscle relaxants and blood-pressure medications.
- Contraindications
- Severe kidney impairment (the kidneys clear excess magnesium; if they're not working, it accumulates). Caution with heart-block / bradyarrhythmia. Caution with myasthenia gravis.
- Lab markers
- RBC magnesium (intracellular magnesium — what actually matters). Serum magnesium is what most labs run by default but it's a poor marker because the body keeps blood levels stable even when tissue is depleted. Target RBC Mg above 5.0 mg/dL.
- Food sources
- Pumpkin seeds, almonds, cashews, spinach, swiss chard, dark chocolate (70%+), avocado, black beans, edamame, tofu, fatty fish (salmon, mackerel). Even a magnesium-rich diet often falls short of optimal intake — supplementation makes up the gap.
Pairs with
Vitamin D3 (magnesium is required to convert D to its active form — supplementing D without magnesium can backfire). L-Theanine (synergistic calming). Glycine (synergistic sleep). Vitamin B6 / P5P (helps magnesium enter cells).
within Minerals