BioStacks
Natural Factors

L-Lysine 500 mg

2 Capsules × 3/day · 45 servings · $0.38/serving

iHerbAmazon

Best for

Immune

Ingredients (1)

L-Lysine

100%

Dose/day

3000 mg

Target

1000–3000 mg

Form

Premium

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.

Magnesium StearateLubricant

A salt of stearic acid used as a lubricant in tablet and capsule production

Silicon DioxideAnti-caking

Fine silica powder used to prevent clumping

Capsule ShellCapsule

Generic capsule shell where the label does not specify the material. Common materials are hypromellose (HPMC) for vegetarian capsules and gelatin for traditional capsules — both are GRAS-listed and safe. Fish gelatin and pullulan variants also exist.

How to Take It

Take it anytime

Take between meals — it competes with arginine for the same transporter.

On an empty stomach
Split into 3 doses across the day

On the label

2 capsules 3 times per day with meals or as directed by a health professional.

Labels usually say “with food” because it's gentler on the stomach, not because it absorbs better. Fasted absorbs more — start there, and switch to a light meal if it bothers you.

General guidance based on the ingredients, not a substitute for the label or your doctor.

Price Check

$16.88

$10$20

Near the median of 53 lysine supplements

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Sources & Scoring

Nutrient data (RDA, UL, and safety thresholds) sourced from the NIH Office of Dietary Supplements and the 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.

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