Pentadecanoic Acid (C15:0) for Health & Longevity - Quick Reference Sheet

Pentadecanoic Acid (C15:0) for Health & Longevity

Created on 09/14/2026 – Quick Reference based on Evidence Review created using AI4L / Opus 5 Audit

A minor saturated fat from dairy and grazing-animal meat, now sold as a capsule. Higher blood amounts track with less diabetes and, less consistently, less heart disease; a genetic analysis found no sign the fat itself does the work. Two small trials moved no measure of weight, waist size or blood sugar. Well tolerated over three months; benefits remain associations. (Full Review)

Protocol

Standard dose
100 mg daily
Free pentadecanoic acid, one capsule; lower than either dose tested in a trial
Trial-matched dose
200–300 mg daily
200 mg in young adults with excess weight; 300 mg alongside a Mediterranean-style diet
Best time of day
Largest fat-containing meal
Absorption follows dietary fat; a single daily dose, no reason to split
Time to effect
Lower LDL cholesterol
12 weeks
The one lipid measure a randomized trial has moved
Liver enzymes, hemoglobin
12 weeks
Only in responders whose blood concentration passed 5 µg/mL
Blood concentration
Still rising at 12 weeks
Had not plateaued; reassessment before three months is premature

Benefits

Contraindications
  • Propionic acidemia or methylmalonic acidemia
  • Untreated vitamin B12 deficiency (B12 below 200 pg/mL or methylmalonic acid above 400 nmol/L) until corrected
  • Pregnant and breastfeeding women
  • Children and adolescents under 18
Key Interactions
  • Lipid-lowering drugs (atorvastatin, rosuvastatin, ezetimibe, bempedoic acid): additive, not adverse
  • Fat-absorption blockers (orlistat, bile-acid sequestrants such as cholestyramine, colesevelam): four-hour separation preserves uptake
  • Over-the-counter products (mineral oil, activated charcoal, psyllium and other bulk fibers): four-hour separation preserves uptake
  • Vitamin B12 and biotin supplements: no caution required; additive and desirable
  • Cannabinoid products (cannabidiol, tetrahydrocannabinol) and sedatives: theoretical caution only
  • Omega-3 fatty acids (eicosapentaenoic acid, docosahexaenoic acid): caution, mechanism-level only
  • Dairy-fat intake and ruminant meat: additive by definition

Risk & Side Effects

  • Medium: Cost without demonstrated clinical benefit; loss of pentadecanoic acid as an interpretable biomarker
  • Low: No safety data beyond twelve weeks or above 300 mg daily; added saturated fat on the dairy route
  • Speculative: Lipotoxicity at concentrations above the dietary range; impaired glucose handling in pregnancy

Monitoring

Marker Target Why
Pentadecanoic acid (C15:0), plasma or red cell Above 0.4% of total fatty acids; trial response threshold above 5 µg/mL Confirms absorption and identifies responders
Alanine aminotransferase (ALT) 10–25 U/L Liver-cell stress; the measure that moved in responders
Aspartate aminotransferase (AST) 10–25 U/L Pairs with ALT to separate liver from muscle sources
LDL cholesterol Below 100 mg/dL; below 70 mg/dL with established plaque The one lipid measure a trial has moved
Apolipoprotein B Below 80 mg/dL Counts every plaque-forming particle, not just cholesterol carried
Glycated hemoglobin (HbA1c) 4.8–5.4% Tracks the diabetes association that underpins the whole benefit case
Fasting insulin 2–6 µIU/mL Detects insulin resistance years before glucose rises
Hemoglobin and red cell distribution width Hemoglobin mid-reference range; RDW below 13% The red-cell claim, and the primary endpoint of the 2027 trial
High-sensitivity C-reactive protein Below 1.0 mg/L Tests the anti-inflammatory claim made from cell studies
Vitamin B12 and methylmalonic acid B12 above 500 pg/mL; methylmalonic acid below 250 nmol/L Odd-chain fats clear through a B12-dependent enzyme

Cadence: Baseline, then the identical panel at 12 weeks, again at 6 months, then every 12 months

Qualitative Assessment

  • Sleep quality and time to fall asleep, given the marketed but untested sleep claim
  • Daytime energy and perceived exercise recovery
  • Cognitive clarity and concentration during the working day
  • Skin and hair condition, the other claim with no supporting study
  • Digestive comfort in the first two weeks, when any tolerance issue would appear