Role of magnesium supplementation in the treatment of depression: A randomized clinical trial.
This trial compared taking magnesium against taking nothing, with everyone knowing which they were on — how much of that improvement would you expect from any pill in that setup?
Well-supported by good-quality research. how we score evidence
Caveat on this rating: Open-label with a no-treatment control rather than a placebo. That single design choice makes the headline 6-point PHQ-9 improvement uninterpretable as a drug effect: placebo responses of that magnitude are routine in depression trials, and here nothing separated the magnesium effect from the effect of knowingly starting a treatment. The authors' conclusion that "magnesium is effective for mild-to-moderate depression" outruns what an unblinded design can show.
Oral magnesium sold for mood, anxiety, or sleep is a dietary supplement under the Dietary Supplement Health and Education Act of 1994 (DSHEA).
One hundred twenty-six primary-care adults with mild-to-moderate depression (PHQ-9 scores 5-19) took 248 mg of elemental magnesium daily for six weeks and no treatment for six weeks, in randomized order. PHQ-9 scores improved by a net 6.0 points (95% CI 4.2-7.9) and anxiety scores on the GAD-7 by 4.5 points during the magnesium periods, with effects appearing within two weeks and good tolerability. The crucial caveat is in the design: the control condition was no treatment at all, and neither participants nor investigators were blinded, so a large share of that 6-point improvement is the expectation of being treated.
Worth asking
This trial compared taking magnesium against taking nothing, with everyone knowing which they were on — how much of that improvement would you expect from any pill in that setup?
Source
Role of magnesium supplementation in the treatment of depression: A randomized clinical trial. — Tarleton EK, Littenberg B, MacLean CD, Kennedy AG, Daley C. (2017)
Indexed peer-reviewed journal
Read the source: https://doi.org/10.1371/journal.pone.0180067
DOI: 10.1371/journal.pone.0180067
How this was scored
- Study design
- Randomised controlled trial
- Funding
- Independently funded
- Published in
- Indexed peer-reviewed journal
- Sample size
- 126
- Preregistered
- No
- Conflicts disclosed
- Yes
- Independent of proponent
- Yes
- Retracted
- No
Read the full scoring rubric, including what it can't tell you.
Published August 19, 2026.
Where we put this study in context
Questions
How strong is the evidence behind this?
Resolv rates this source "strong evidence". Well-supported by good-quality research. It scores 76 out of 100 on our published rubric. One caveat travels with that badge: Open-label with a no-treatment control rather than a placebo. That single design choice makes the headline 6-point PHQ-9 improvement uninterpretable as a drug effect: placebo responses of that magnitude are routine in depression trials, and here nothing separated the magnesium effect from the effect of knowingly starting a treatment. The authors' conclusion that "magnesium is effective for mild-to-moderate depression" outruns what an unblinded design can show. The score is calculated from recorded facts about the source — study design, funding, publication venue, sample size, preregistration — not typed in by an editor.
What is the source for this?
Role of magnesium supplementation in the treatment of depression: A randomized clinical trial. — Tarleton EK, Littenberg B, MacLean CD, Kennedy AG, Daley C. (2017). Published in: Indexed peer-reviewed journal. DOI: 10.1371/journal.pone.0180067. The full source is linked on this page so you can read it yourself.
Who paid for this research, and does that matter?
Study design: Randomised controlled trial. Funding: Independently funded. The researchers were independent of whoever benefits from the result. Industry sponsorship is one of the most reliably measured biases in medicine, which is why funding carries real weight in the score rather than sitting in a footnote.
Is magnesium, magnesium glycinate, magnesium citrate, magnesium oxide, magnesium chloride, magnesium aspartate, magnesium l-threonate, magtein, epsom salts FDA approved for this use?
No. Its current status is: Not FDA-evaluated for this use. Oral magnesium sold for mood, anxiety, or sleep is a dietary supplement under the Dietary Supplement Health and Education Act of 1994 (DSHEA).
Is this medical advice?
This is information to bring to your prescriber, not medical advice and not a reason to change anything on your own. Nothing here is an instruction to stop or reduce a medication. If you are in crisis, call or text 988.
This is information to bring to your prescriber, not medical advice and not a reason to change anything on your own. Nothing here is an instruction to stop or reduce a medication. If you are in crisis, call or text 988.