Magnesium glycinate Side Effects: What Reddit Users Report
44 of 370 Reddit owner comments about Magnesium glycinate (12%) describe an unwanted effect. The effects people mention most are grogginess, drowsiness or fatigue, racing heart or palpitations and trouble sleeping or feeling wired. These are self-reports from Reddit anxiety, stress and supplement communities (May 2026 to October 2026), not a measured side-effect rate, and many people report no problems at all.
Magnesium glycinate overall: 4.0 · tolerability 4.4 (higher means fewer unwanted-effect reports).
What people describe
| Effect mentioned | Owner comments |
|---|---|
| Grogginess, drowsiness or fatigue | 4 |
| Racing heart or palpitations | 4 |
| Trouble sleeping or feeling wired | 4 |
How we counted: among the 44 comments that describe an unwanted effect, a category counts when a sentence names the effect with wording like "gave me" or "made me". Questions and sentences about an effect going away are skipped. One comment can count in more than one row, and keyword counts can include some unrelated mentions, so read the quotes below for context.
Most common complaints
- Side effects: 33 owner comments
- Stomach upset: 4 owner comments
- Mood: 4 owner comments
Safety notes from NIH and published research
- The NIH upper limit for magnesium from supplements is 350 mg a day for adults; higher doses commonly cause diarrhea, nausea and abdominal cramping.[NIH Office of Dietary Supplements]
- Magnesium can reduce the absorption of some antibiotics (tetracyclines, quinolones) and bisphosphonates, so the NIH advises spacing the doses apart.[NIH Office of Dietary Supplements]
Stop and talk to a doctor if an effect is severe or does not settle. Ask a pharmacist about interactions with any medicine you take.
In their words
4/5 GrogginessSide effects“For example, magnesium bisglycinate works wonders for my girlfriend's anxiety, whereas when I have it (and I've tried multiple times) I get an immense grogginess and depression the next day.”
2/5 MoodSide effects“I also have ADHD and also can't tolerate magnesium glycinate.”
5/5 Stomach upsetSide effects“I have to take it with food so it doesn't upset my stomach, but other than magnesium glycinate, it has been the most life changing supplement that I've found.”
2/5 GrogginessSide effects“Yeah, I've tried time and time again with Magnesium Glycinate, but it just leaves me depressed and groggy the next day.”
2/5 Calming effectSide effects“Its called paradoxical reaction and its to the glycinate.”
4/5 Side effectsFalling asleep“I started taking Mg glycinate several years ago after literally decades of searching for a solution to morning anxiety --- waking up with an uncomfortable rush of cortisol and feeling very anxious.”
1/5 Side effects“Like you, glycinate was terrible for me.”
2/5 Feeling flat or numbMood“Glycinate makes me depressed / gives me anhedonia...”
Frequently asked
What side effects do people report with Magnesium glycinate?
44 of 370 Reddit owner comments about Magnesium glycinate (12%) describe an unwanted effect; the ones mentioned most were grogginess, drowsiness or fatigue, racing heart or palpitations and trouble sleeping or feeling wired. These are self-reports, not a measured side-effect rate.
Is Magnesium glycinate safe?
Safety depends on your health and medicines. The NIH and other sources listed on this page note specific cautions. Ask a doctor or pharmacist before starting, especially if you take other medicines or are pregnant.
More on Magnesium glycinate
Compare side-effect reports: Magnesium glycinate vs Magnesium L-threonate (Magtein) · Magnesium glycinate vs Magnesium (form not stated) · Magnesium glycinate vs Magnesium taurate · L-theanine vs Magnesium glycinate · GABA vs Magnesium glycinate · Glycine vs Magnesium glycinate