As per my advice to never use a supplement without verifying its quality via a Certificate of Analysis, I obtained the COA for Innovixabs Magnesium Glycinate Malate.
Cadmium (Cd), Mercury (Hg) are extremely low. Arsenic (Ar) is low.
Lead (Pb) for InnovixLabs Magnesium Glycinate Malate
This comparison equalizes the single-dose amount of elemental magnesium serving size at 210mg.
InnovixLab: 0.18 mcg lead per 210mg elemental Mg (0.1 mcg per 115 elemental Mg)
Nutricost: 0.0109 mcg per 210mg elemental Mg
ReMag: 0.651 mcg lead per 210mg elemental Mg (0.465 mcg lead per 150mg elemental Mg)
Doublewood: 0.146 mcg lead per 210mg elemental Mg (0.1 mcg per 144mg elemental Mg)
Lead content of the InnovixLabs is low, about ~23% higher than the Doublewood magnesium L-Threonate but only 27% as much as the ReMag MgCl. The low-lead winner is the Nutricost MgCl which has 16X lower lead (Pb than the InnovixLabs product.
Of course, if the actual absorption of the magnesium varies between product type, the figures would be subject to some adjustment. But it’s hard to beat 16X lower.
The California recommended maximum total lead intake for a pregnant woman is 0.5 mcg per day. It would be hard to meet that just eating food! Still, it’s a metric with a large margin of safety for anyone, and by that metric the InnovixLab and Doublewood and Nutricost products all pass for a daily intake of ~400mg elemental magnesium, a reasonable daily adult maintenance dose.
My personal cutoff threshold is strict due to a desire to mitigate a high blood lead level: no more than 0.5 mcg per day from ingesting ~600mg elemental magnesium, because anyone at magnesium deficiency might take 1200mg or even 2000mg per day—which I did for 4-5 months back in 2020, regrettably and unknowingly with high-lead ReMag. That factor of up to ~10X more (2000mg vs 210mg Mg) means that the only acceptable product for high dosing is the Nutricost which would still be only 0.1 mcg lead for 2000mg elemental magnesium intake.