— Guide
Magnesium Bisglycinate vs. Citrate: Which is Better for Sleep?
Walk down any supplement aisle and you'll see magnesium sold in a dozen different forms. Two of the most common are magnesium bisglycinate and magnesium citrate. They sound similar, but they behave very differently in the body - and that difference matters most in the evening, when you want a supplement that supports a calm wind-down rather than a trip to the bathroom.
What the form actually means
Pure magnesium is a metal; supplements always bind it to another molecule. That partner molecule determines two things: how much elemental magnesium each capsule delivers, and how the body absorbs and tolerates it.
- Magnesium bisglycinate binds magnesium to two molecules of the amino acid glycine. Glycine itself is calming and is used by the body during sleep.
- Magnesium citrate binds magnesium to citric acid. It is inexpensive, widely available and well absorbed - but the citrate part also draws water into the intestine, which is why it's a common ingredient in laxatives.
Absorption: both good, with a catch
Both forms are considered well-absorbed compared with cheaper magnesium oxide. Citrate tends to be a touch higher on paper, but bisglycinate's chelated structure passes through the gut wall through amino-acid pathways, which is gentler on a sensitive stomach.
Gut tolerance: the deciding factor at night
This is where the two forms split. Magnesium citrate's mild laxative effect is a feature if you're using it for constipation. It's a problem if you're taking magnesium an hour before bed and would rather not wake up at 3 a.m. Bisglycinate is consistently described in the literature as the most gut-friendly of the well-absorbed forms.
Glycine: the quiet bonus
With bisglycinate, you're not only getting magnesium - you're also getting glycine, an amino acid the body uses as an inhibitory neurotransmitter. Small studies have linked glycine before bed to improved sleep quality and a quicker time to fall asleep. With citrate, there's no comparable second ingredient.
Which one belongs in an evening ritual?
If your goal is regularity or rapid magnesium repletion, citrate has its place. If your goal is a calm, repeatable evening habit - the kind you take at the same hour every night without worrying about side effects - bisglycinate is the better fit.
That's why NIGHT. is built around magnesium bisglycinate, paired with saffron and L-theanine. A formula measured for the evening, not the morning bathroom schedule.