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Magnesium Lactate

An organic magnesium salt that is absorbed reasonably well and is gentler on the gut than oxide. Good for correcting low magnesium; the form itself has little direct trial evidence.

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What the science says

  • Absorption compared with magnesium oxide Moderate evidence

    A comparative bioavailability study of commercial magnesium preparations in humans found organic salts, including magnesium lactate, produced greater urinary magnesium excretion — a proxy for absorption — than magnesium oxide. The study was small, and comparisons across organic salts were not decisive.

  • Correcting magnesium status Moderate evidence

    A physiological review of magnesium in humans describes the consequences of deficiency and the role of oral repletion in people with low intake, malabsorption or losses from diuretics and proton pump inhibitors. This is the well-supported reason to take any magnesium salt.

  • Blood pressure Limited evidence

    A randomized controlled trial of a magnesium L-lactate supplement in women with metabolic syndrome reported effects on blood pressure and corrected QT interval. It was a single small trial and does not establish a cardiovascular benefit for this form.

Dosage & safety

Studied doseTypical supplements give 84–200 mg of elemental magnesium per dose; the recommended daily allowance is 310–420 mg total from all sources. The upper limit for supplemental magnesium in adults is 350 mg/day of elemental magnesium, above which diarrhoea becomes likely.
SafetyThe main effect is loose stools, less pronounced than with magnesium oxide or citrate. Magnesium accumulates in kidney impairment and can cause dangerous hypermagnesaemia — avoid supplements if your kidney function is reduced unless supervised. It reduces absorption of tetracyclines, quinolones and bisphosphonates, so separate doses by at least 2 hours. People with a rare inability to clear lactate should choose another salt.

How to take it

TimingEvening suits most people, both for tolerability and because magnesium is often taken for sleep or cramps.
With food?With food, which reduces the loose-stool effect.
Worth knowingRead the elemental magnesium figure, not the salt weight — a 500 mg magnesium lactate capsule contains only about 60 mg of actual magnesium.

Interactions

With medications

  • tetracycline and quinolone antibiotics

    Magnesium chelates these antibiotics in the gut and can cut absorption enough to cause treatment failure. separate by at least 2 hours, taking the antibiotic first

  • levothyroxine

    Magnesium reduces thyroid hormone absorption and can destabilise a settled dose. separate by at least 4 hours

  • bisphosphonates such as alendronate

    Absorption of the bisphosphonate is markedly reduced. take the bisphosphonate on an empty stomach and keep magnesium several hours away

With other supplements

  • other magnesium salts, including magnesium in multivitamins and laxatives

    Doses add up and diarrhoea follows. count total elemental magnesium, not the number of products

Well-established interactions only — this is not a complete list. Always tell your doctor and pharmacist what you take.

Frequently asked questions

Is magnesium lactate well absorbed?

Yes, reasonably: a small human study found organic salts including magnesium lactate were absorbed better than magnesium oxide, with moderate evidence. It is also gentler on the gut than oxide.

How much magnesium lactate should I take?

Supplements typically give 84-200 mg of elemental magnesium per dose, and the adult upper limit for supplemental magnesium is 350 mg/day. Read the elemental figure: a 500 mg magnesium lactate capsule contains only about 60 mg of magnesium.

Does magnesium lactate lower blood pressure?

The evidence is limited to a single small trial of magnesium L-lactate in women with metabolic syndrome, which does not establish a cardiovascular benefit.

Can I take magnesium lactate with antibiotics or levothyroxine?

Separate them: magnesium lactate can cut absorption of tetracycline and quinolone antibiotics enough to cause treatment failure, so take the antibiotic first and wait at least 2 hours, and keep it at least 4 hours from levothyroxine. Avoid it with reduced kidney function unless supervised.

Scientific references

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