BioStacks
Best for
Ingredients (4)
Zinc
100%Dose
15 mg
Target
15–30 mg
Form
Standard
Vitamin C
100%Dose
250 mg
Target
250–2000 mg
Form
Budget
N-Acetyl-L-Cysteine
50%Dose
300 mg
Target
600–1800 mg
Form
—
Echinacea Purpurea Flower and Leaf
33%Dose
100 mg
Target
300–1500 mg
Form
—
Other Ingredients (4)
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.
Silicon DioxideAnti-caking
Fine silica powder used to prevent clumping
Vegetable StearateLubricant
A plant-derived salt of stearic acid (typically magnesium or calcium) used as a tablet lubricant
GelatinCapsule
Protein derived from collagen, used in traditional capsule shells
How to Take It
Take it anytime
Take with food — on an empty stomach it commonly causes nausea.
With food
NAC does better on an empty stomach, but something else in this bottle needs food. Taking the whole product with a meal is the better trade — an upset stomach is why most people stop.
Space it a couple of hours from Iron and Calcium
On the label
Take two (2) capsules per day, preferably with a meal, or as recommended by your health-care practitioner.
General guidance based on the ingredients, not a substitute for the label or your doctor.
Price Check
$39.00
Pricier than 70% of 292 immune 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. studied 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.