Semaglutide
Semaglutide is a GLP-1 receptor agonist originally developed for type 2 diabetes, now widely used for weight management (Wegovy) and showing promising longevity and cardiovascular benefits. It mimics the incretin hormone GLP-1, reducing appetite, slowing gastric emptying, and improving insulin sensitivity.
Evidence Summary
Landmark SELECT trial (n=17,604) demonstrated 20% reduction in major cardiovascular events. STEP trials showed 15-17% mean weight loss. FLOW trial showed kidney protective effects. Over 100 ongoing trials investigating neurological, liver, and longevity applications. Preclinical geroscience update (Sep 2026): in a peer-reviewed Nature study (Feng…Chen, 2 Sep 2026), semaglutide started at 20 months of age in female C57BL/6 mice extended median lifespan by ~12% (834 vs 742 days), improved endurance, spatial memory and glucose control, enhanced stem-cell regenerative capacity, and attenuated transcriptomic ageing hallmarks — recapitulating and in some domains exceeding matched calorie restriction. This is the first lifespan result for a GLP-1RA begun late in life. It is mouse-only, female-only and single-site; it does not establish a longevity effect in humans, where the only randomised ageing-biomarker signal to date is a ~9% slowing of PCGrimAge pace in a specific HIV-lipohypertrophy cohort (Nat Commun 2026).
Evidence Scale
Mechanism of Action
Binds to GLP-1 receptors in the pancreas (enhancing insulin secretion), hypothalamus (reducing appetite), and cardiovascular system (reducing inflammation). Also crosses the blood-brain barrier, influencing reward pathways and reducing food-seeking behavior. Emerging evidence suggests anti-inflammatory and neuroprotective effects.
Who Is This For?
BMI ≥30, or BMI ≥27 with weight-related comorbidity. Type 2 diabetes. Cardiovascular risk reduction in established disease. Off-label: metabolic optimization in longevity protocols.
Protocol & Dosing
Dose
Injectable: Start 0.25mg weekly, escalate monthly to 0.5mg → 1mg → 1.7mg → 2.4mg. Oral (Rybelsus): 3mg daily for 30 days, then 7mg, then 14mg. Take oral form on empty stomach with ≤4oz water, 30 min before food.
Frequency
Weekly injection or daily oral
Duration
Ongoing / Long-term
Protocol Summary
Weekly subcutaneous injection (Ozempic 0.5-2mg for T2D, Wegovy 2.4mg for weight management) or daily oral tablet (Rybelsus). Dose escalation over 16-20 weeks to minimize GI side effects. Combine with resistance training to preserve lean mass.
Interactions & Precautions
Contraindications
- Personal or family history of medullary thyroid carcinoma
- Multiple endocrine neoplasia syndrome type 2 (MEN2)
- History of pancreatitis
- Severe gastroparesis
- Pregnancy or breastfeeding
Potential Risks
- •Thyroid C-cell tumor risk (preclinical, boxed warning)
- •Lean mass loss without exercise countermeasures
- •Rebound weight gain upon discontinuation
- •Potential for gallstone formation
Potential Side Effects
Practitioner Notes
Clinical annotations from Dr. Goel
Monitor for GI tolerance during dose escalation. Recommend concurrent resistance training program to mitigate lean mass loss. Check amylase/lipase if abdominal symptoms. Consider thyroid ultrasound baseline. Assess body composition (DEXA) at baseline and quarterly. Compounded versions lack quality assurance — recommend FDA-approved formulations. Sep 2026: the Nature late-life mouse lifespan result (Feng…Chen) strengthens the calorie-restriction-mimetic rationale but should not be cited to patients as evidence that semaglutide extends human lifespan. Weigh against sarcopenia risk in older adults; body-composition monitoring and resistance training remain the priority. Watch the UTMB Moody tirzepatide-vs-epigenetic-clock trial and SURMOUNT-MMO for human ageing/mortality endpoints.
Dr. Sanjeev Goel
Chief Medical Officer, Peak Human
Cost & Access
Cost Range
$$$$
Accessibility
Availability varies by location
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