Key Terms
Concise definitions for terms used throughout this guide
The following definitions are provided for quick reference. Full context for each appears in the relevant section of the guide.
Adaptogen
A category of herbal compounds, including ashwagandha, marketed for supporting the body's response to stress. Evidence quality varies substantially by specific compound and extract.
Bioavailability
The degree to which a supplement's active ingredient is actually absorbed and usable by the body — the reason specific forms (e.g. magnesium glycinate over oxide, triglyceride-form omega-3 over ethyl ester) are recommended over others.
Menaquinone (Vitamin K2)
The form of vitamin K found in fermented foods and some animal products, distinct from the K1 found in leafy greens. Associated with directing calcium toward bone rather than arterial tissue.
NAD+ (Nicotinamide Adenine Dinucleotide)
A molecule essential for cellular energy production and DNA repair, which reliably declines with age. NMN and NR are precursor supplements that raise NAD+ levels — see the Longevity guide for the full evidence picture.
Proprietary Blend
A supplement formulation that discloses a combined total dose of several ingredients without specifying each ingredient's individual amount. See Section 8 for why this is treated as a red flag in this guide.