This nighttime formula pairs **Magnesium** at 200mg with **Melatonin** at 2.5mg — both comfortably within their clinical ranges for sleep support. The magnesium comes as a glycinate-oxide blend, so you're getting a mix of well-absorbed and poorly-absorbed forms rather than pure glycinate. At 200mg elemental, it's enough to contribute meaningfully to relaxation and muscle function, especially if your diet already covers part of your daily need.

**GABA** is sourced from PharmaGABA, a fermented form that may absorb better than synthetic versions. At 100mg you're at the floor of the studied range — enough to potentially take the edge off, though the evidence for oral GABA crossing the blood-brain barrier is still debated. **Melatonin** at 2.5mg is a moderate dose that should help with sleep onset without the grogginess that higher doses can cause.

The weakest link is **L-Theanine** at just 50mg — half the minimum clinical dose of 100mg used in relaxation studies. If calming support from theanine is important to you, you'd need to supplement it separately to reach the 100–200mg range where the research shows benefit.

BioStacks
Natural Factors

Stress-Relax Nighttime Magnesium Glycinate With Melatonin, GABA & L-Theanine

2 Capsules · 30 servings · $0.65/serving

iHerbAmazon

Best for

SleepStress & Mood

Ingredients (4)

Melatonin

100%

Dose

2.5 mg

Target

0.5–5 mg

Form

—

Magnesium

100%

Dose

200 mg

Target

100–400 mg

Form

Premium

Gamma-aminobutyric acid (GABA)

100%

Dose

100 mg

Target

100–300 mg

Form

Premium

L-Theanine

50%

Dose

50 mg

Target

100–250 mg

Form

—

Other Ingredients (5)

Rice FlourFiller

Rice-based ingredients carry risk of inorganic arsenic contamination (FDA and Consumer Reports). Rice accumulates arsenic from soil at higher rates than other grains. Used as a cheap filler — adds nothing beneficial.

Magnesium StearateLubricant

A salt of stearic acid used as a lubricant in tablet and capsule production

Silicon DioxideAnti-caking

Fine silica powder used to prevent clumping

Stearic AcidLubricant

Saturated fatty acid used as tablet lubricant

Capsule ShellCapsule

Generic capsule shell where the label does not specify the material. Common materials are hypromellose (HPMC) for vegetarian capsules and gelatin for traditional capsules — both are GRAS-listed and safe. Fish gelatin and pullulan variants also exist.

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Sources & Scoring

Nutrient data (RDA, UL, and safety thresholds) sourced from: NIH Office of Dietary Supplements and National Academies Dietary Reference Intakes (DRI).

This is not medical advice. Consult a healthcare provider before making changes to your supplement routine.

The score analyzes what's on the label: ingredient doses vs. clinical ranges, chemical forms, evidence levels, and known interactions. It does not verify label accuracy or test for contaminants — for that, look for third-party certifications like USP or NSF.

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