Everything DoseRank tracks on the grapefruit seed extract shelf — Zinc Amino Acid Chelate. The category itself is never ranked: 8 products get scored the moment you say what you want them to do.
How to read the scores
This legend covers the scores on this page — for data sources, scoring weights, and limits, read the full methodology →
Answer a few questions about your goals, habits, stack, and budget. Then, DoseRank will find the products that best match your needs based on your answers. It's free and only takes 60 seconds! No account is required.
A saved, shareable breakdown: your matched products, dose math, interaction flags to discuss with a clinician, and a price-tracked stack you can revisit.
Questions
Each product gets a composite score blending clinical strength, evidence, dose fit, trust and value — computed for the goal you picked, across this category's products. The #1 on the DoseRank tab has the highest composite; the other tabs re-rank the same products by Value, Trust, or Popularity. Placement is never paid.
A category alone does not say what you want the product to do. The same category can lead on sleep for one shopper and stress for another, and the evidence behind each pick differs. Picking the medical outcome first lets DoseRank rank this category's products against that outcome's studies and doses.
No. Dose-fit rewards landing inside the range studied for the outcome — over-dosing (common with melatonin) or under-dosing both lower the score. The goal is the effective dose, not the biggest number.
The Value score compares a product's price per serving with clinically relevant products ranked for the same outcome. A score of 50 is the typical price; above 50 means better value than typical, while below 50 means the product costs more than typical. It is a 0–100 value signal, not a percentile.
Cost is only one input. A cheap pick can trail on the composite when it uses a weaker form, misses the studied dose, or carries a stock-risk flag — the composite also weighs evidence, dose fit and availability.
Retailer links may be affiliate links and DoseRank may earn a commission. Rankings and placement are determined by the scoring model only — never by payment from a brand.
No. DoseRank summarizes evidence to help you choose; it is not a substitute for a clinician, especially if you are pregnant, breastfeeding, on medication, or managing a health condition.
Start with a goal, not a brand
Browsing grapefruit seed extract supplements without a goal makes no sense — different products do different jobs, and “best” flips depending on which job you're hiring for. These are the 7 health outcomes that matter for this category. Pick yours, and the full evidence-ranked shelf loads for that goal alone.
Zinc statusBiochemical sufficiency of zinc.6 rankedStrong
Vitamin C statusBiochemical sufficiency of ascorbic acid.6 rankedStrong
Vitamin E statusBiochemical sufficiency of tocopherols/tocotrienols.4 rankedStrong
Immune functionAbility of the immune system to respond appropriately.8 rankedStrong
Acne severityExtent or intensity of acne lesions.6 rankedModerate-strong
Sperm motilityAbility of sperm to move effectively.4 rankedModerate-strong
Antioxidant capacityMeasured ability to counter oxidative stress.6 rankedStrongNothing is ranked yet — the shelf stays locked until you pick a goal.
No goal, no ranking.
A “best grapefruit seed extract supplement” list without a goal would be marketing, not evidence. Pick what you want to improve and DoseRank scores all 8 products against that goal's trials.