Lysine is an essential amino acid and multi-gram oral supplement studied for recurrent cold sores, stress hormones, and calcium handling. For adults with adequate protein, the strongest signal is modest support against frequent cold-sore outbreaks at 1–3 grams daily. Safety is generally good; gastrointestinal symptoms define a provisional ceiling near six grams daily. Broad longevity claims remain early or unproven. (Full Review)
| Marker | Target | Why |
|---|---|---|
| Basic metabolic panel (BMP) / comprehensive metabolic panel (CMP) | eGFR and electrolytes in optimal personal range; calcium mid-normal | Detects kidney stress and calcium shifts |
| Serum calcium (total ± ionized) | Mid-reference (lab-specific); avoid high-normal creeping on high Ca intake | Lysine can increase Ca absorption |
| 25-hydroxyvitamin D | Often ~40–60 ng/mL in functional practice | Bone/Ca context if using lysine for Ca balance |
| Urinary calcium (spot Ca/Cr or 24-h) | Within lab reference; watch upward shifts | Captures calciuria changes |
| Plasma amino acids (optional) | Lysine within reference; balanced essential amino acid pattern | Confirms free-lysine rise / screens imbalance |
| CBC (complete blood count) | Within personal baseline | General safety on long-term supplements |
Cadence: Baseline, then at 4–8 weeks after stable multi-gram dose, then every 6–12 months if continued long-term