BioStacks
Best for
Ingredients (2)
PurCaf Organic Caffeine
100%Dose
100 mg
Target
100–400 mg
Form
—
L-Theanine
100%Dose
100 mg
Target
100–250 mg
Form
Premium
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.
Bamboo ExtractFiller
Plant-derived silica source used as a natural anti-caking agent and carrier (silica content ~70%)
Rice HullsAnti-caking
Ground outer husk of rice grains used as a plant-based flow and anti-caking agent
Gum AcaciaBinder
Natural plant gum (acacia) used as a binder, stabilizer, and emulsifier in foods and supplements
HypromelloseCapsule
Plant-derived capsule material from cellulose
How to Take It
Best taken in the morning
Morning or early afternoon only — caffeine within 8 hours of bed measurably disrupts sleep.
With or without food
On the label
Take one to four servings (1-4 capsules) per day with or without food. Don't exceed four servings (4 capsules) per day.
General guidance based on the ingredients, not a substitute for the label or your doctor.
Price Check
$39.99
Pricier than 77% of 118 theanine supplements
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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.