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Magnesium types — cheat sheet

Every form, sorted by relevance to autism, sleep, and nervous system support. Use this alongside Video 2 of the Magnesium & Autistic Sleep series.

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Most relevant — autism, sleep & nervous system

Form	Absorption	Best for	Notes for autism & sleep
Magnesium glycinate Also: bisglycinate, diglycinate	High	Sleep onset, nervous system calm, anxiety, sensory overload	The first-line form for autistic children and sleep. Glycine has its own calming effect on the nervous system — it works alongside magnesium rather than just carrying it. Well tolerated, gentle on digestion, unlikely to cause loose stools at standard doses. The starting point before considering anything else.
Label note: "500 mg magnesium glycinate" is the compound weight. Elemental magnesium is typically only 50–100 mg of that. Always check elemental magnesium on the label — that's the number that matters for dosing.
Magnesium L-threonate Brand name: Magtein	High (brain)	Brain-level calm, deep sleep quality, cognitive support	The only form clinically shown to cross the blood-brain barrier and raise magnesium directly in brain tissue. Developed at MIT. Relevant when the primary problem is a brain that won't quiet — racing thoughts, inability to disengage at bedtime. More expensive. Evidence in children specifically is still developing. Works well alongside glycinate, not instead of it.
Magnesium taurate	High	Anxiety-dominant profile, nervous system calm	Taurine has its own calming effect on the nervous system and supports GABA function. Smaller evidence base than glycinate, but potentially useful where anxiety is the dominant feature at bedtime. Less commonly available in Canada.
Magnesium citrate	Medium–high	General replenishment, constipation relief	Well absorbed and less expensive than glycinate. Useful if constipation is also present — take earlier in the day for that purpose. Not ideal at night — the laxative effect can be disruptive. If constipation and sleep are both concerns: citrate in the morning + glycinate in the evening is a reasonable combination.
Magnesium malate	High	Energy production, muscle pain, daytime fatigue	Paired with malic acid, which is involved in cellular energy production. Not primarily a sleep or nervous system form, but relevant if daytime fatigue and poor energy are significant alongside sleep issues. Gentle on digestion. Sometimes used for fibromyalgia.

Situationally relevant — specific use cases

Form	Absorption	Best for	Notes
Magnesium chloride	High	General replenishment, topical use	Well absorbed orally. Also available as a topical oil or spray — skin absorption is modest, but applying it as part of a calm pre-bed routine can be a useful sensory ritual. Not a substitute for oral supplementation if correcting deficiency is the goal.
Magnesium sulfate Epsom salts	Topical / bath	Pre-bed bath, muscle relaxation ritual	Skin absorption of magnesium from Epsom salt baths is debated in the research — likely modest. The real mechanism: warm water raises core body temperature; stepping out causes a temperature drop, which is one of the body's own signals to begin sleep onset. The bath itself is regulating and useful as a bedtime ritual, regardless of absorption.
Magnesium orotate	High	Cardiovascular support, cellular energy	Carries magnesium closer to the nucleus and mitochondria. Often discussed for heart health and athletic performance. Not a primary choice for sleep or autism-related nervous system support, but a legitimate form when cardiac or energy considerations are relevant.
Magnesium lactate	High	Sensitive stomachs, gentle daily use	Very gentle on the digestive system. A reasonable alternative if glycinate is unavailable or not tolerated. Supports muscle function. Less commonly found on Canadian pharmacy shelves — more likely in health food stores.
Magnesium aspartate	Medium–high	Fatigue, general deficiency	Has been studied for chronic fatigue. Absorption is reasonably good. Aspartate can be mildly excitatory in larger amounts — not the first choice for a child whose nervous system is already running high. Limited availability in Canada.
Magnesium gluconate	Medium	Mild deficiency, gentle option	Low elemental magnesium content per dose — requires larger quantities to reach therapeutic levels. Gentle and unlikely to cause digestive upset. Not commonly recommended as a primary option for this context.

Not useful here — skip or avoid

Form	Absorption	Common use	Why to avoid here
Magnesium oxide	Very low (~4%)	Laxative, antacid, budget supplements	Only about 4% is absorbed — the rest passes through. The most common form in grocery store supplements and cheap multivitamins. If a family has "tried magnesium and it didn't work," this is usually why. Also: research suggests it may reduce absorption of certain antipsychotic medications by altering stomach pH — specifically relevant for children on risperidone or similar. Avoid for this population.
Magnesium hydroxide Milk of Magnesia	Poor	Laxative, antacid	Strong laxative effect. Not appropriate for correcting deficiency or supporting sleep. Occasional use for acute constipation only — not for ongoing supplementation.
Magnesium carbonate	Poor	Antacid	Primarily used as an antacid. Low bioavailability as a dietary supplement. Not appropriate for correcting magnesium deficiency.
Magnesium phosphate	Trace / homeopathic	Homeopathic tissue salts	Found in Schuessler tissue salt preparations. Extremely low doses — not meaningful for correcting deficiency. Not a dietary supplement in any clinical sense.
Magnesium pidolate Pyrrolidone carboxylate	Medium	General supplementation (Europe)	Used in some European formulations. Not commonly available in Canada or the US. Limited research. No specific advantage for sleep or autism-related nervous system support over glycinate.
Magnesium silicate	None	Industrial / food additive	An anti-caking agent found in some powdered food products. Not a dietary supplement. No nutritional value for magnesium levels.

Quick Decision Guide

→Sleep difficulties, high sensory load in evenings, no digestive issues → magnesium glycinate, 60–90 min before bed routine begins
→Sleep difficulties + constipation → citrate in the morning, glycinate in the evening
→Brain won't quiet at bedtime, racing thoughts → glycinate + consider adding L-threonate
→Anxiety is the dominant evening feature → glycinate or taurate
→Child is on antipsychotics (risperidone etc.) → avoid oxide specifically, use glycinate, inform prescriber
→Child is on stimulants (ADHD medication) → magnesium depletion is more likely; glycinate appropriate, inform prescriber
→Child is on anticonvulsants → speak with prescribing neurologist before adding any magnesium
→Child has kidney issues → speak with doctor first — kidneys regulate magnesium excretion

Always check elemental magnesium on the label, not compound weight. A "500 mg magnesium glycinate" capsule typically contains only 50–100 mg of elemental magnesium. Start at the lower end of the age-appropriate dose and increase slowly over 2–4 weeks. Speak with your child's doctor before starting, particularly if your child is on any medication.

This chart is part of the Magnesium & Autistic Sleep video series. For the full context — what magnesium does in the body, where research supports its use, and how to have the conversation with your doctor — watch the playlist at The Evolution of Sleep on YouTube.

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