Here's the direct primary for this one (Skrypnik et al., Antioxidants, 2021, open access) with the actual measured numbers - and they're refreshingly honest, which makes them more trustworthy, not less.
Antioxidant strength, quantified
The researchers measured shungite's radical-scavenging power and reported it in the standard equivalents chemists use. The best sample (20 µm, heat-treated) came in at:
- 1.63 mg/g ascorbic-acid (vitamin C) equivalents
- 2.19 mg/g trolox (vitamin-E analogue) equivalents
- 1.11 mg/g quercetin equivalents
The honest framing the authors give: shungite's antioxidant action is real and measurable, but on a per-gram basis it's
"approximately 1000 times less pronounced than quercetin" (one of the strongest plant antioxidants). So it's a genuine, gentle, slow-release radical scavenger - not a megadose. For a rock you put in water, measurable vitamin-C-equivalent activity at all is the interesting part.
Particle size and heat-treatment matter
Finer particles (20 µm) and a heat-treatment step both raised the activity - the same "smaller and activated works harder" pattern that shows up across the shungite literature.
Cytotoxicity
Tested on HEK293 human cells (Alamar Blue method). The heat-treated 20 µm sample showed the most cytotoxic activity of the samples - a reminder that "natural" and "inert" aren't the same thing, and that dose and particle size are real variables.
(The same paper's mycotoxin-adsorption results - aflatoxin, ochratoxin and four others bound at 81-100% - are covered in their own thread on this forum.)
Source
- Skrypnik L. et al. (2021), "A Study of the Antioxidant, Cytotoxic Activity and Adsorption Properties of Karelian Shungite by Physicochemical Methods", Antioxidants (Basel) 10(7):1121:
pmc.ncbi.nlm.nih.gov
