Magnesium L-Threonate for Sleep: Two Trials, Different Outcomes

The three-week study favored some scores, not more sleep

A 2024 trial¹ randomized 80 adults aged 35–55 to 1 g/day of magnesium L-threonate or placebo for 21 days; 76 completed. The compound supplied about 75 mg of elemental magnesium.¹

Awakening behavior and Oura’s deep- and REM-sleep scores favored treatment. However, total sleep time and deep-sleep minutes did not improve significantly more than placebo. Overall insomnia-score improvement did not significantly exceed placebo, although some later comparisons were favorable. AIDP funded the study.¹

The six-week study found a narrower sleep benefit

The 2026 trial² randomized 100 adults aged 18–45, using 2 g/day, supplying 145 mg elemental magnesium, for six weeks. Its primary outcome was cognitive performance, rather than sleep.²

Self-rated sleep-related impairment improved by 6.35 points versus 3.38 with placebo. But overall sleep disturbance, restorative-sleep ratings and Oura sleep measures showed no significant group differences. Threotech funded the trial and helped design it.²

An October 15, 2026 correction clarifies that the analyses used two-tailed tests. The original wording was wrong; the reported results were unchanged.³

These were separate placebo comparisons, not a head-to-head dose trial or a comparison with glycinate.¹²

Match a claim to the outcome measured

Ring-generated stage scores are not minutes in that stage. Neither trial used laboratory sleep recordings.¹²

Before trying a product, write down the change you want: fewer remembered awakenings, less difficulty getting through the morning or a shorter wait to fall asleep. Keep that question separate from whether a device gives you a higher score.

Compare elemental amounts on the label

NIH guidance explains that Supplement Facts lists elemental magnesium, not the whole compound’s weight. The adult upper limit is 350 mg/day from supplements and magnesium-containing medicines, excluding food; it is not a sleep-treatment target.⁴

Supplemental magnesium can cause diarrhea, nausea and cramps. Kidney impairment increases toxicity risk, and magnesium can interfere with absorption of certain antibiotics and oral bisphosphonates. Ask a pharmacist to check the exact product, other magnesium sources and medicine timing.⁴

“The Watch Can Take a Night Off” in Did I Do That in My Sleep? treats consumer-device data as estimates and offers a diary focused on daily functioning. Our general magnesium-and-sleep guide covers the older-adult evidence separately.