ThorneMagnesium Bisglycinate

The practical details.

Before you buy

Evidence & sources.

Do creatine, fish oil, vitamin D and magnesium work? Our evidence review grades the research as Mixed. That grade is about the claim, not about this product.

• CertificationNSF's Certified for Sport database lists "Thorne® Magnesium Bisglycinate" by Thorne as a mineral powder. The listing gives a serving size of 1 scoop (3.77 g) and a package size of 7.98 oz (226.2 g). It lists the flavor as unflavored, a gluten free claim and the United States as the country of sale. It shows 21 certified lot numbers. It's the only magnesium product in NSF's Thorne results.^{3, 5} Checked in NSF's own database (listing 1507934), not just taken from the mark on Thorne's page. The listing shows no SKU, product code or certification date. You can match the lot number on your tub to the listed lots. A sport certification is about what's in the product, not about health effects.
• Manufacturer claimThorne's product page shows the NSF Certified for Sport mark. Thorne says the mark means the product was tested for label claims and for the absence of nearly 300 substances banned by major athletic organizations. Thorne also says it tests each ingredient for identity, purity and potency, including checks for heavy metals, pesticides and harmful microbes.¹ These are Thorne's own statements. The page doesn't publish Thorne's test results.
• Manufacturer claimThorne says the powder promotes restful sleep and muscle relaxation, and that it's well tolerated and well absorbed. Its FAQ says it may support relaxation, heart, muscle and sugar metabolism, and sleep quality. The page carries the standard notice that the FDA hasn't evaluated these statements. It cites no studies.¹ These are Thorne's marketing claims for a dietary supplement, and none is tied to a study on the page.
• Independent testNIH's Office of Dietary Supplements sets the adult Tolerable Upper Intake Level at 350 mg a day. That limit counts magnesium from supplements and medications, not food. It says high doses from supplements or medications can cause diarrhea, nausea and abdominal cramping. The limit is lower for young children: 65 mg at ages 1 to 3 and 110 mg at ages 4 to 8. It also lists interactions with bisphosphonates, tetracycline and quinolone antibiotics, diuretics and long-term use of proton pump inhibitors.⁴ One 200 mg scoop is under the adult limit, with 150 mg to spare for any other supplement or medicine. NIH advises taking bisphosphonates at least 2 hours apart from magnesium, and these antibiotics at least 2 hours before or 4 to 6 hours after it. Thorne's page says there are no known adverse interactions as of its publication date. The fact sheet doesn't discuss the bisglycinate form.
• Published studyA 2025 randomized, double-blind, placebo-controlled trial enrolled 155 adults in Germany, aged 18 to 65, who reported poor sleep (Schuster and colleagues, Nature and Science of Sleep). They took 250 mg of magnesium a day as magnesium bisglycinate, or a placebo, for four weeks. Insomnia Severity Index scores fell 3.9 points with magnesium and 2.3 points with placebo. The difference was small (Cohen's d 0.2) and only just significant (p = 0.049). Other sleep, stress and mood measures showed no significant difference between groups. No serious adverse events were reported.⁶ The trial didn't test Thorne's product. It used capsules made by Biogena, at 250 mg a day, more than one 200 mg scoop. Sleep was self-reported only, and the trial lasted four weeks. About 80% of participants were women. Leibniz University Hannover funded it, and one author directs a contract research organization that receives funding from supplement companies.