Comparison
Sermorelin vs Tirzepatide
Side-by-side of Sermorelin and Tirzepatide. Every row below is pulled from the compound schema and will update as our data grows. For deeper reads, follow through to each compound page.
Sermorelin
Sermorelin peptide therapy uses a 29-amino-acid GHRH analog to raise endogenous GH. Dosing, half-life, sermorelin vs ipamorelin, and safety.
Tirzepatide
Tirzepatide for weight loss: dual GIP/GLP-1 agonist sold as Mounjaro and Zepbound. SURMOUNT-1 showed 22.5% mean body-weight loss at 15 mg over 72 weeks.
Effects at a glance
Sermorelin
- •Synthetic 29-amino-acid GHRH fragment; FDA approved 1997 for pediatric GH deficiency as Geref
- •Voluntarily discontinued by Serono in 2008 for commercial reasons; not safety-related
- •Compounded by 503A/503B pharmacies for off-label adult anti-aging and body-composition use
- •Produces physiologic pulsatile GH release; ~10 to 20 minute plasma half-life
- •Standard anti-aging clinic protocol: 200 to 500 mcg subcutaneously pre-bed, often with ipamorelin
- •Banned by WADA under S2 (peptide hormones, growth factors)
Tirzepatide
- •Dual GIP plus GLP-1 receptor agonist with a ~5-day half-life supporting once-weekly subcutaneous dosing
- •SURMOUNT-1 reported ~22.5% mean body-weight loss at 15 mg over 72 weeks versus 2.4% on placebo
- •Lowers HbA1c by ~1.9 to 2.6 percentage points in type 2 diabetes across SURPASS trials
- •Outperformed semaglutide 1.0 mg head-to-head on weight loss and HbA1c in SURPASS-2
- •GI effects (nausea, diarrhea, vomiting) drive most discontinuations and ease with slow titration
- •Lean-mass loss observed in body-composition substudies; resistance training and protein intake mitigate this
Side-by-side
| Attribute | Sermorelin | Tirzepatide |
|---|---|---|
| Category | peptide | pharmaceutical |
| Also known as | Sermorelin acetate, GRF 1-29, Geref, GHRH (1-29) NH2 | Mounjaro, Zepbound, LY3298176 |
| Half-life (hr) ↗ | 0.25 | 120 |
| Typical dose (mg) ↗ | 0.3 | 10 |
| Dosing frequency | 1-2x daily | weekly |
| Routes | subcutaneous | subcutaneous |
| Onset (hr) | 0.25 | 24 |
| Peak (hr) | 0.5 | 72 |
| Molecular weight | 3357.88 | 4813.45 |
| Molecular formula | C149H246N44O42S | C225H348N48O68 |
| Mechanism | Synthetic 29-amino-acid GHRH fragment that binds the GHRH receptor on pituitary somatotrophs to stimulate endogenous pulsatile GH synthesis and release while preserving the GH-IGF-1 negative feedback loop. | Synthetic 39-amino-acid peptide that activates both GIP and GLP-1 receptors. Potentiates glucose-dependent insulin secretion, suppresses glucagon, slows gastric emptying, and acts on hypothalamic and brainstem satiety circuits. |
| Legal status | FDA approved 1997 (Geref, pediatric GHD); voluntarily discontinued by Serono 2008; compounded by 503A/503B pharmacies for off-label adult use; banned by WADA | Prescription only; FDA-approved 2022 (T2DM, Mounjaro) and 2023 (chronic weight management, Zepbound) |
| WADA status | banned | allowed |
| DEA / Rx | Rx only via compounding (no controlled-substance schedule) | Rx only (not a controlled substance) |
| Pregnancy | Category C (historical labeling); not recommended in pregnancy | Not recommended; discontinue 2 months before planned pregnancy |
| CAS | 86168-78-7 | 2023788-19-2 |
| PubChem CID | 16129617 | 156588324 |
| Wikidata | Q416620 | Q105099794 |
Safety profile
Sermorelin
Common side effects
- injection-site pain or irritation
- transient flushing
- headache
- vivid dreams (pre-bed dosing)
Contraindications
- pregnancy
- active malignancy
- history of pituitary tumor
- diabetic retinopathy (theoretical)
- untreated hypothyroidism
Interactions
- ipamorelin: synergistic GH release via parallel GHRH and ghrelin pathways; standard anti-aging clinic pairing(minor)
- CJC-1295: pharmacologically redundant (both GHRH-pathway); typically not stacked(minor)
- insulin: sustained GH can blunt insulin sensitivity over weeks(moderate)
- corticosteroids: blunt GH response; reduce expected efficacy(moderate)
- levothyroxine (untreated hypothyroidism): untreated hypothyroidism blunts GH response; correct thyroid first(moderate)
Tirzepatide
Common side effects
- nausea
- diarrhea
- vomiting
- constipation
- decreased appetite
- injection-site reactions
- fatigue
- abdominal pain
Contraindications
- personal or family history of medullary thyroid carcinoma
- multiple endocrine neoplasia type 2
- pregnancy
- history of pancreatitis (use caution)
- severe gastroparesis
Interactions
- insulin: additive hypoglycemia risk; insulin dose typically reduced(major)
- sulfonylureas (glipizide, glyburide): hypoglycemia risk, sulfonylurea dose often reduced(major)
- oral medications (general): delayed gastric emptying can alter absorption kinetics(moderate)
- oral contraceptives: reduced exposure after first dose; backup contraception recommended for 4 weeks after initiation and each dose escalation(moderate)
- warfarin: monitor INR due to altered absorption(moderate)
Which Should You Take?
Sermorelin and Tirzepatide score evenly on the criteria we weight (goal breadth, legal accessibility, evidence depth). The conditionals below should drive the decision more than any aggregate score.
- → If your priority is growth-hormone axis, pick Sermorelin.
- → If your priority is healthspan extension, pick Sermorelin.
- → If your priority is metabolic health and glucose control, pick Tirzepatide.
- → If your priority is fat loss, pick Tirzepatide.
Edge case: Half-lives differ materially (Sermorelin ~0.25 hr vs Tirzepatide ~120 hr). Tirzepatide reaches steady state faster; Sermorelin is easier to dial in if tolerability is uncertain.
Default choice: either is defensible. Sermorelin edges out on goal breadth + legal accessibility; Tirzepatide is the right call if your priority sits in the goals listed above.
This verdict is generated from each compound's schema (goals, legal status, evidence outcomes, dosing route). It updates automatically as our compound data evolves; the deeper read sits on each individual compound page.
Common questions
What is the difference between Sermorelin and Tirzepatide?
Sermorelin and Tirzepatide differ in category (peptide vs pharmaceutical), mechanism, and typical dosing. See the side-by-side table for full details.
Which has a longer half-life, Sermorelin or Tirzepatide?
Sermorelin half-life is 0.25 hours; Tirzepatide half-life is 120 hours.
Can you stack Sermorelin with Tirzepatide?
Stack compatibility depends on mechanism overlap, legal status, and individual response. Check each compound page for specific interactions and contraindications before combining.
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