Medium-chain triglycerides (MCT, coconut oil C8–C10)

Medium-chain triglycerides (MCT) are fats from coconut and palm-kernel oil, the C8–C10 fractions. In the anti-aging niche they get promoted as a quick source of energy and ketones that supposedly slows aging and extends lifespan. No convincing benefit for this use has been shown in people: there is no evidence base for life extension or rejuvenation. Healthy lifespan depends far more on sleep, regular physical activity, a balanced diet, and keeping blood pressure, weight, and blood sugar in check.

In obesity (BMI ≥30) MCT is sold as a «natural semaglutide alternative» and essential keto diet component. Meta-analyses showed no clinically meaningful weight reduction in obesity patients adding MCT to diet; effect disappeared on isocaloric replacement of long-chain triglycerides. SEEDO 2022 and NICE 2023 for obesity list as first-line a comprehensive programme (diet, physical activity, behavioural therapy); at BMI ≥30 – GLP-1 receptor agonist pharmacotherapy (semaglutide/Wegovy 2.4 mg/week SC gives mean 15% weight loss at 68 weeks – STEP 1 trial), tirzepatide (Zepbound, SURMOUNT 1 – 21% at 72 weeks), liraglutide, orlistat; at BMI ≥40 (or ≥35 with complications) – bariatric surgery. Keto diet as a weight-loss strategy is not preferred in guidelines: Mediterranean and DASH diets have stronger evidence base and easier long-term adherence. If MCT was recommended as a comprehensive programme substitute in obesity, consider seeking a second opinion from an obesity specialist.

MCT oil is actively sold as a «fat burner» and «weight-loss aid», especially for keto diets and Bulletproof coffee. Mumme and Stonehouse 2015 systematic review (13 RCTs, 749 participants) showed clinically small weight reduction (0.5 kg pooled) and waist circumference change when replacing long-chain triglycerides with MCT 20–30 g/day × 4–16 weeks. Body composition impact minimal. NICE 2023 (CG189) and SEEDO 2022 for obesity list as first-line a comprehensive programme: hypocaloric diet, physical activity ≥150–300 min/week, behavioural therapy; at BMI ≥30 (or ≥27 with complications) – pharmacotherapy (semaglutide/Wegovy with real 15% loss, liraglutide, tirzepatide, orlistat); at BMI ≥40 (or ≥35 with complications) – bariatric surgery. MCT is not in obesity guidelines. High calorie density (9 kcal/g) makes it impractical as a «fat burner»: 30 mL MCT = 250 kcal. If MCT was recommended as weight-loss monotherapy, consider seeking a second opinion from an endocrinologist or dietitian.