Labdoor's Label Accuracy score is based on a comparison of a product's label claims for active ingredient content vs. the actual measured quantities of these ingredients.
For scoring purposes, products begin at a 10 out of 10 score, and are then penalized if measured values don't match claimed values. Products are penalized twice as severely for having less of a nutrient than claimed (underage) compared to having more of the nutrient than claimed (overage). In multiple-ingredient products, label accuracy scores for individual nutrients are combined to generate a final Label Accuracy score.
Labdoor's Product Purity score is based on the levels of known contaminants in a product.
Labdoor's default purity assessment consists of heavy metal assays. Depending on the supplement category, additional contaminant screenings may be performed. Whenever possible, testing data is compared to the lowest levels of these contaminants published by state, federal, and international health organizations with definitions for their potential effects on human health. These can include proposed and established Maximum Allowable Dose Levels (MADLs) and No Significant Risk Levels (NSRLs) from California's Prop 65, Reference Doses (RfDs) from the US Environmental Protection Agency (EPA), and Minimal Risk Levels (MRLs) from the US Agency for Toxic Substances and Disease Registry (ATSDR). This procedure was adopted for Labdoor's more recent supplement categories. Older categories relied on penalizing products for heavy metal quantities above available laboratory detection limits. As these categories are retested, grades will be updated to follow suit.
California's Office of Environmental Health Hazard Assessment (OEHHA) states that "the purpose of Proposition 65 is to notify consumers that they are being exposed to chemicals that are known to cause cancer and/or reproductive toxicity. Consumers can decide on their own if they want to purchase or use the product. A Proposition 65 warning does not necessarily mean a product is in violation of any product-safety standards or requirements."
Labdoor's Nutritional Value score is based on a product's macronutrient load and the addition of other supporting nutrients.
Products are rewarded and penalized for their macronutrient content based how much those macronutrients in one serving meet or exceed their established recommendations for daily intake. Assessed macronutrients include, but are not limited to, calories, fat, cholesterol, carbohydrates, sodium, and sugar. If a product contains other supporting components like secondary vitamins and minerals, their levels are also compared to Dietary Reference Intakes (DRIs) and factored into the product's final Nutritional Value score. If DRIs are not applicable, an evaluation of peer-reviewed research and meta-analyses is performed to ascertain relevant thresholds.
Labdoor's Ingredient Safety score is based on an assessment of whether a product has too much of an active ingredient that it becomes unsafe, and the presence and severity of any additives.
Products are penalized as their active ingredient levels approach or exceed established Tolerable Upper Intake Levels (ULs). The National Institutes of Health (NIH) defines ULs as "the highest level of nutrient intake that is likely to pose no risk of adverse health effects for almost all individuals in the general population. As intake increases above the UL, the risk of adverse effects increases." When ULs have not been established, other applied thresholds may include No-Observed-Adverse-Effect Levels (NOAELs), Minimal Risk Levels (MRLs), or values derived from an evaluation of peer-reviewed research.
Each product's additives, or excipients, are also assessed for their potential effects on human health. These ingredients are assigned weights based on FDA "Generally Recognized As Safe" (GRAS) status, the quality of research surrounding their safety, and the severity of their potential risks. Related points are then applied to a product's final Ingredient Safety score.
Labdoor's Projected Efficacy score is based on the quantity of a product's active ingredients and their specific biochemical properties.
Each active ingredient in a product is evaluated based on how much of the ingredient is actually present and how well the body can absorb and use it. The latter can be attributed to a variety of factors, including the bioavailability of a certain ingredient form (e.g. zinc oxide versus zinc citrate), an ingredient's pharmacokinetic (PK) profile, the concentration of any key ingredient components (e.g. EPA and DHA in fish oil), and whether the specific combination of ingredients in a product affects active ingredient absorption. Bioavailability indicates what fraction of a nutrient's dose reaches systemic circulation. A PK profile is a quantitative representation of how an administered substance is absorbed and distributed. This information is curated from peer-reviewed clinical studies and meta-analyses as well as expert consultations. Scores for individual active ingredients are combined to generate a final Projected Efficacy score.
*New products are tested and existing products are re-tested regularly. New research is also constantly reviewed and new methods are applied whenever they prove to increase accuracy. As such, Labdoor retains the right to update scoring algorithms, product data, and rankings at any time. Updates are published here.