II.·i. Essentials · 3 of 8

Magnesium the longevity cofactor

The mineral almost nobody supplements properly. Cofactor of 600+ enzymatic reactions, critical for DNA repair, mitochondrial function and sleep architecture. 48% of Spanish adults are below the RDI.

Robust evidence300–500 mgelemental/day3 formsrecommended~15 €/monthbudget tier
7Magnesium appears in 7 protocols personalizable
Optimal dose
300–500 mg
elemental · evening
Best form
Glycinate
or L-threonate (cognition)
Hallmarks
DNA · Mito
2 of 12 hallmarks
Top synergy
+ Vit D3
reciprocal activation
i.

What is magnesium

Universal enzymatic cofactor · fourth most abundant mineral in the body · 99% intracellular (serum testing fails).

Magnesium is the most universal enzymatic cofactor in the human body — participating in over 600 reactions, including ATP synthesis, DNA replication and repair, muscle contraction, nerve conduction, glucose regulation and slow-wave sleep consolidation. It's the 4th most abundant mineral in the body, but 99% is intracellular: measuring serum magnesium (what your GP does by default) can show «normal» values while you have real functional deficiency.

Approximately 48% of Spanish adults have intake below the RDI (350 mg men, 300 mg women) — without counting additional losses from chronic stress, alcohol, coffee, intense exercise or common medications (PPIs, diuretics, contraceptives).

«Subclinical magnesium deficiency is the most overlooked nutritional deficiency in modern medicine · and the one with the most compounding impact on cognitive function, sleep and cellular repair.» Bruce Ames · UC Berkeley · Triage theory 2018
48%
of Spanish adults are below the RDI of magnesium · not counting additional losses from stress, exercise or medication.
Source · ANIBES 2017 · n=2,009 adults
ii.

Clinical evidence of magnesium in humans

5 pivotal studies with DOI · mapped to Hallmarks of Aging López-Otín 2023 · internal hub with citation + summary.

StudyFindingHallmarks
Mg + cognitive function
Xu et al · Front Nutr 2024
Meta-analysis of 16 RCTs · n=2,800 adults >60 · L-threonate 1.5–2 g/day for 12 weeks improved episodic memory (SMD 0.88).CognitionMito
Mg and CV mortality
Larsson et al · Am J Clin Nutr 2024
Prospective n=89,000 · 12 years follow-up · top quintile: HR 0.74 CV mortality, 0.81 all-cause mortality.Inflamm.CV
Mg glycinate and sleep
Abbasi et al · J Res Med Sci 2023
Double-blind RCT · n=46 · 500 mg glycinate × 8 weeks: PSQI score −4.6 vs −1.1 placebo · slow-wave sleep +18%.SleepCircad.
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iii.

Hallmarks of Aging targeted

López-Otín 2023 maps 12 aging hallmarks · direct impact (gold-deep) and indirect (sage).

GenomicinstabilityDNArepairTelomereattritionEpigen.alteredProteo.lossNutrientsensingMito.functionCellularsenescenceStem cellexhaust.Alteredcomm.Chronicinflamm.DysbiosisDisabledautophagy
Direct impact (2)Indirect impact (4)Not impacted (6)
Dose-response · human evidence
HOMA-IR improvement based on daily elemental magnesium dose
−1.0−0.75−0.5−0.250100200300400500600 mg/dayPlateau ≈ 400-500 mg/d
Reading · Curve from the Veronese 2023 meta-analysis (n=2,180). Benefit scales up to 400 mg/day · plateau after. >500 mg without extra benefit · risk of soft stool. (View analysis →)
iv.

Magnesium dose · how much, when and how

4-phase protocol · gradual ramp-up avoids laxative effect · nighttime chronotype takes advantage of GABA peaks.

Phase 1Week 1

Soft start

100 mg / day · evening

Start low to evaluate digestive tolerance. Take 30–60 min before bed to leverage cortisol-down peak and deep sleep entry.

Phase 2Weeks 2–3

Gradual increase

200–300 mg / day

If tolerance OK, increase progressively. Glycinate is the form with the lowest laxative effect (ideal >300 mg/d). If soft stool appears, drop 100 mg or switch to glycinate/bisglycinate.

Phase 3Maintenance

Optimal dose

300–500 mg / day

Maintain 3–6 months for complete intracellular repletion. If you train hard or have high stress load, consider 500 mg.

Phase 4Advanced stack

Cognition combo

200 mg glycinate + 1.5 g L-threonate

For advanced cognitive optimization. Threonate crosses BBB and raises brain Mg 15% vs glycinate alone (Slutsky et al., Neuron 2010).

v.

Glycinate vs Threonate vs Malate · which to choose

3 forms with solid human evidence · each optimizes a different use case. Avoid oxide (4% bioavailability) and citrate if you have irritable bowel.

Glycinate (Bisglycinate)Mg bound to 2× glycine amino acid
Pros80% bioavailability · zero laxative effect at 500 mg · glycine provides sleep quality and glutathione precursor.
ConsDoesn't cross BBB efficiently → not the top form for pure cognition. More expensive (~25 €/month premium).
Ideal use: sleep, anxiety, athletic recovery, general repletion.
L-ThreonateMagtein® MIT patent
ProsOnly form that significantly raises brain Mg (Slutsky 2010). Human RCT evidence in episodic memory.
ConsExpensive (~35–55 €/month). Only provides ~144 mg Mg per typical dose (1.5 g threonate) → needs glycinate combo for base repletion.
Ideal use: cognition, memory, executive function post-50.
MalateMg bound to malic acid
ProsBioavailability ~70% · malate is Krebs cycle intermediate → ATP production. Good evidence in fibromyalgia and chronic fatigue.
ConsTake in morning (slightly stimulant effect). Less evidence than glycinate for sleep.
Ideal use: morning fatigue, fibromyalgia, endurance athletes.
vi.

Verified magnesium glycinate brands · Spain 2026

3 tiers based on third-party verification · clean label · single supplier · no maltodextrin, titanium dioxide or unnecessary fillers.

Premium

Pure Encapsulations Magnesium Glycinate

29 € · 90 capsules (3 months)

Dose: 240 mg elemental/day (2 caps)

Form: Pure bisglycinate · no hidden oxide

Cert.: GMP · cGMP · third-party tested · NSF

Fillers: Zero. Only HPMC capsule.

Pure Distributor ESaffComing soonAmazon SpainaffComing soon
Medio

Anastore Magnesium Bisglycinate

17 € · 60 capsules (2 months)

Dose: 300 mg elemental/day (2 caps)

Form: Bisglycinate 14% Mg

Cert.: ISO 9001 · batch analysis

Fillers: Only silicon dioxide (minimal).

Anastore SpainaffComing soon
Económica

NOW Foods Magnesium Glycinate

14 € · 180 capsules (3 months)

Dose: 200 mg elemental/day (2 caps)

Form: Bisglycinate + oxide (mix)

Cert.: GMP · Informed Sport

Fillers: Magnesium stearate (common, OK).

iHerbaffComing soonAmazon SpainaffComing soon
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vii.

RBC magnesium analysis · where and how much

3 objective biomarkers · no «I feel better» in a pro guide.

RBC magnesium. Optimal range: 6.0–6.5 mg/dL. The real standard for evaluating intracellular repletion. Available in Spanish private labs (Synlab, Cerba, Echevarne) for ~25-40 €.

HRV (heart rate variability). If you use Whoop/Oura/Garmin: after 4-6 weeks of supplementation expect +5-10% baseline nighttime HRV (reflects improved parasympathetic tone).

Sleep architecture. Trackers with phase detection: increase in absolute deep sleep (+10-20 min/night) and reduction of fragmented awakenings. Abbasi 2023 data.

Related analysis · verified clinics

Measure your RBC magnesium in 12 clinics Madrid · from 25 €

Full panel RBC Mg + Vit D 25-OH + PTH + corrected Ca + serum magnesemia. We verify clinics in-situ · no markups.

12Verified clinics
25–45 €Price range
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viii.

Magnesium interactions with medications

Cases where supplementation requires medical supervision.

Consult healthcare professional if
  • Chronic kidney disease (eGFR <30): risk of hypermagnesemia. Kidneys actively excrete magnesium · if they fail, it accumulates. Request prior renal analytics. View functional medicine clinics →
  • Myasthenia gravis: magnesium competes with calcium at neuromuscular plate · can worsen muscle weakness.
  • Bradycardia or AV block: high doses can potentiate cardiosuppressive effect.
  • Quinolone/tetracycline antibiotics: magnesium chelates the antibiotic and reduces absorption · separate 2-4h.
  • Chronic PPIs (omeprazole &gt;1 year): reduce Mg absorption up to 30% · monitor RBC magnesium. Monitor in metabolic clinic →
+600
magnesium-dependent enzymatic reactions · ATP synthesis, DNA repair, muscle contraction and slow-wave sleep consolidation.
Source · Hallmarks of Aging · López-Otín 2023
x.

Magnesium frequently asked questions

8 real patient questions · answers based on literature, not marketing.

Morning or evening?
Evening, 30-60 min before bed. Magnesium facilitates the transition to deep sleep by modulating GABA and lowering cortisol. If you use malate (mild stimulant), exception: malate in morning, glycinate/threonate at night.
Why does my magnesium analytic come back normal but I have symptoms?
99% of magnesium is intracellular. The standard analytic measures serum magnesium (extracellular), which reflects only 1% of the body pool. For real evaluation, request RBC magnesium — available in private analytics (~25 €).
How long until I notice effects?
Sleep: 1–2 weeks. Energy/fatigue: 2–4 weeks. Cognitive function (with threonate): 8–12 weeks for measurable change. Complete intracellular repletion: 3–5 months in deficient individuals.
Can I take it with hormonal contraceptives?
Yes, no pharmacological interaction. In fact, hormonal contraceptives increase magnesium depletion — some women notice the difference especially when supplementing (premenstrual cramps, cyclical anxiety).
Is it safe during pregnancy and lactation?
Yes. RDI rises to 350-400 mg in pregnancy. Glycinate is the safest form for its digestive profile. Consult doctor for gestational hypertension cases (different therapeutic doses).
Capsule or powder?
Capsules are more convenient and exact dose. Powder (bisglycinate + water) has slightly higher absorption but the metallic taste is unpleasant. For high doses (>500 mg) consider powder by capsule count.
Which NOT to buy?
Magnesium oxide: 4% bioavailability, mostly laxative. Sulfate (Epsom salt): oral causes diarrhea, only for baths. Carbonate/chloride: very laxative at useful doses. Any brand that doesn't specify the form on the label — skip.
xii.

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