HGH Fragment 176-191 vs Spermidine
Side-by-side comparison of key properties, dosing, and research.
Fat Loss & Metabolic
HGH Fragment 176-191Anti-Aging & LongevityCognitive Enhancement
Spermidine- Summary
- HGH Fragment 176-191 (also known as AOD-9604) is a stabilized, modified fragment of the human growth hormone molecule corresponding to amino acids 176–191 with an addition of a tyrosine residue at the N-terminus. It retains HGH's fat-burning properties without the anabolic, diabetogenic, or IGF-1-stimulating effects.
- Spermidine is a naturally occurring polyamine found in all living cells, with exceptionally high concentrations in wheat germ, aged cheese, and human sperm. It is the most studied autophagy-inducing dietary compound, shown to extend lifespan across multiple species and reduce cardiovascular and cognitive aging.
- Half-Life
- ~30 minutes
- ~30–60 minutes, but gut bacteria produce it continuously; supplementation raises tissue levels over weeks
- Admin Route
- SubQ
- Oral
- Research
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- Typical Dose
- 250–500 mcg
- 1–5 mg
- Frequency
- 1–3 times daily
- Once daily
- Key Benefits
- Selective fat burning without anabolic side effects
- Reduces visceral and subcutaneous fat
- No insulin resistance or blood glucose disruption
- Does not stimulate IGF-1
- May support cartilage and bone repair (at higher doses)
- No effect on growth or organ size
- Induces autophagy — cellular self-cleaning
- Extends lifespan in yeast, flies, worms, and mice
- Reduces cardiovascular aging and arterial stiffness
- Reduces all-cause mortality (human epidemiological data)
- Neuroprotective: reduces amyloid and tau pathology
- Promotes hair growth (anagen phase activation)
- Reduces age-related immune decline
- Improves memory in aging models
- Side Effects
- Injection site irritation
- Temporary lethargy
- Headache (rare)
- Nausea (rare)
- Generally very well tolerated
- Rare: mild GI discomfort at high doses
- May temporarily reduce some gut bacteria species
- Rare: headache at initiation
- Stacks With
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