What does magnesium and testosterone do?

Column one, the threads, and column two, the register, which are the two sources most readers have met

What magnesium and testosterone do is a question best answered in three columns, because the two sources most readers have met disagree and the third settles it. Column one, the threads: forum posts on magnesium and testosterone report that magnesium boosts testosterone, raises free testosterone by displacing it from its binding protein, improves libido and morning erections, and belongs in every natural test stack, with a smaller number of posts reporting nothing, and all of it first-person, unblinded and self-selected, the forum epistemology guide's standing point that a thread is evidence of experience and not of effect, and that a lifter who takes magnesium expecting a hormonal change will report the feel of one. Column two, the register, which the careful-claims flag on this page holds: magnesium has no authorised testosterone claim, its sentences being normal muscle function, nervous system function, psychological function, energy-yielding metabolism, protein synthesis and the reduction of tiredness and fatigue, and the only testosterone sentence on the whole register is zinc's, a contribution to the maintenance of normal testosterone levels in the blood, maintenance of a normal level and not a boost, so no magnesium product may say what the threads say and a product that does has printed an unlawful claim. The binding-protein story in the threads deserves its own line: the idea that magnesium frees testosterone from sex-hormone-binding globulin comes from the observational study in older men described below, an association and not a mechanism shown to work in a capsule.

Column three, the studies, which settle it, and the three columns filed

Column three, the studies, in the order they are cited. The observational study: in a cohort of older men, serum magnesium was associated with testosterone and IGF-1, the higher the magnesium the higher the hormones, a cross-sectional association in a population where low magnesium travels with poor diet, illness and inactivity, which cannot show that magnesium causes testosterone and is the origin of the binding-protein story. The athlete trial: a small four-week study gave magnesium to sedentary men and athletes with and without exercise and reported higher testosterone, particularly after exhausting exercise, in a sample whose baseline status was not established and whose finding has not been replicated, graded here as a small study rather than a result. The trained-men trial: the independent replication of the ZMA formula, delivering 450mg of magnesium and 30mg of zinc daily to trained men over eight weeks of resistance training, found no effect on total or free testosterone, on other anabolic or catabolic hormones, on strength or on body composition, the cleanest test of adding magnesium to men who were not short of it and a null. Read together, the studies say what the deficiency pattern says for every nutrient: an association in men whose low magnesium came with everything else that lowers testosterone, a suggestion in a small trial, and nothing in replete trained men, so that magnesium restores whatever a genuine shortfall was costing and does not raise a replete man above his own normal. The three columns filed: the threads say boost, the register says no such sentence, the studies say an association, a suggestion and a null, and low testosterone, with fatigue, low libido, low mood or lost strength, is a GP's morning blood test and not a mineral, the worked example being magnesium taken for muscle function and fatigue at 300mg elemental with no hormone word, £19.99 for 90 days at 22p.

The verdict, three columns and the studies settle it

What do magnesium and testosterone do: the threads say magnesium boosts testosterone and frees it from its binding protein, the register allows no such sentence and gives the only testosterone claim to zinc as maintenance, and the studies settle it with an observational association in older men, one small unreplicated athlete trial and a null result in trained men taking 450mg a day, the deficiency pattern in which a shortfall repleted restores a man's own normal and a replete man rises nowhere, with low testosterone being a GP's morning blood test. Taken for the sentences it holds: Futuro Labs Magnesium Glycinate, bisglycinate, 300mg elemental at 80% NRV, £19.99 for 90 days at 22p a day, no hormone word on the label.

What to check on the label

Questions people also ask

Does magnesium boost testosterone like the forums say?

No: the register allows no such claim, and the studies show an observational association in older men, one small unreplicated athlete trial and a null result in trained men taking 450mg a day, the pattern of a shortfall restored rather than a level raised.

Does magnesium increase free testosterone by lowering SHBG?

That story comes from a cross-sectional association between serum magnesium and testosterone in older men, where low magnesium travels with poor diet and illness; no trial has shown a magnesium capsule raising free testosterone in replete men.

What did the study of magnesium in trained men find?

The independent ZMA trial, delivering 450mg of magnesium and 30mg of zinc daily over eight weeks of resistance training, found no effect on total or free testosterone, other hormones, strength or body composition.

Can magnesium help with low testosterone?

Only where a genuine magnesium shortfall was part of the picture, and then by restoring a man's own normal; low testosterone with fatigue, low libido, low mood or lost strength has many causes and is a GP's morning blood test.

What supplement can legally claim to support testosterone?

Zinc, and only as maintenance: the register authorises that zinc contributes to the maintenance of normal testosterone levels in the blood, with no supplement permitted to claim a boost.

Sources

1. Maggio M, et al. Magnesium and anabolic hormones in older men. International Journal of Andrology 2011: an observational association between serum magnesium and testosterone and IGF-1 in older men, not a trial of supplementation. PubMed record
2. Cinar V, Polat Y, Baltaci AK, Mogulkoc R. Effects of magnesium supplementation on testosterone levels of athletes and sedentary subjects at rest and after exhaustion. Biological Trace Element Research 2011;140(1):18-23. PubMed record
3. The GB claims register, zinc entries: zinc contributes to the maintenance of normal testosterone levels in the blood, to normal fertility and reproduction, to normal immune function and to the maintenance of normal skin, hair and nails, among others, at 15% NRV or more. https://www.gov.uk/government/publications/great-britain-nutrition-and-health-claims-nhc-register
4. Prasad AS, Mantzoros CS, Beck FW, Hess JW, Brewer GJ. Zinc status and serum testosterone levels of healthy adults. Nutrition 1996;12(5):344-348. PubMed record

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