It is marketed as a proprietary formula "enhancing the diversity of microbiome" by making the gut environment friendlier to the "growth of 20,000-30,000 different strains of good gut bacteria", improving "their communication" and enabling them "to work together". 1 teaspoon of Restore contains 150 mg of stabilized Lignite extract (trademarked as Terrahydrite) and purified water (less than 1% of: chloride, sodium, lithium, calcium, phosphorus, sulfur, bromide, potassium, iron, atimony, zinc, copper, gold, magnesium, alanine, glycine, histidine, isolucine, methionine, threonine, valine.)
Terrahydrite is said to tighten gut junctions and improve digestive health.
Lignite is technically a type of poor quality coal - a sedimentary rock formed from compressed peat mined all over the world. It is generally used as a fuel for generating electricity.
There are over 300 reviews on Amazon; 2 at gnc.com, 2 at jet.com, also 4 short reviews from summer 2016 at prohealth.com.