5-Aminolevulinic Acid — The Heme Precursor and Mitochondrial Activator

5-Aminolevulinic acid (5-ALA) is a non-proteinogenic amino acid and the universal precursor for heme biosynthesis in mitochondria. Exogenous 5-ALA enhances mitochondrial function by increasing the production of heme and activating the electron transport chain, particularly cytochrome c oxidase (Complex IV). It also induces the expression of heme oxygenase-1 (HO-1), which degrades heme into carbon monoxide, biliverdin, and ferrous iron, exerting potent antioxidant and anti-inflammatory effects. Furthermore, 5-ALA has been shown to upregulate PGC-1α, promoting mitochondrial biogenesis and improving glucose and lipid metabolism.

Human trials of 5-ALA (often combined with sodium ferrous citrate) have demonstrated improvements in glucose tolerance in prediabetic individuals and reductions in fasting blood glucose. Other trials have shown it can reduce feelings of chronic physical fatigue and improve sleep quality. No published human longevity trials exist. Animal/in-vitro evidence suggests it may mitigate age-associated declines in locomotor function and extend lifespan in models like Drosophila.

15–50 mg/day of 5-ALA (often combined with sodium ferrous citrate) is the most studied range in human metabolic and fatigue trials. Some studies use up to 250 mg/day. It is typically taken orally. For photodynamic therapy, much higher doses (e.g., 20 mg/kg) are administered under medical supervision.

Oral supplementation of 5-ALA at low doses (15–50 mg/day) is generally well-tolerated with minor gastrointestinal side effects occasionally reported. High doses used in photodynamic therapy can cause photosensitivity, requiring patients to avoid direct sunlight for a period after administration. It should be used with caution in individuals with porphyria or liver dysfunction.

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