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Incretin & metabolic

HGH Fragment 176-191

Also known as hGH Fragment 176-191, Fragment 176-191, Frag 176-191, Tyr-hGH 177-191 (AOD-9604): surrogate studied in humans, identity with the formulary product unconfirmed

Limited human dataTier C applies to the safety summary only (surrogate AOD-9604, oral and IV, efficacy negative). The practice dosing section is tier D: community-reported, with no human or pharmacokinetic validation and no subcutaneous data. A peer-reviewed 2026 review rates AOD9604 'tier-B/C' with 'limited interpretable signals' (PMID 42395176).

Synthetic C-terminal fragment of human growth hormone (investigational, lipolysis-targeted peptide)

Not FDA-approved. Not on FDA's 503A category lists (May 14, 2026). Source, May 14, 2026

Identity. HGH Fragment 176-191 and AOD-9604 are separate products on the formulary and are not interchangeable. AOD-9604 is Tyr + hGH 177-191 (16 residues, cyclized by a Cys-Cys disulfide, MW 1,815.09 g/mol, C78H123N23O23S2 per FDA; sequence YLRIVQCRSVEGSCGF). It is commonly sold under the '176-191' label. A plain hGH 176-191 fragment may also be sold. WADA-related analytical literature treats AOD-9604 and hGH 176-191 as separate analytes (PMID 42328738). No study was found of a molecule sold under the exact name '176-191'. All human data below are for AOD-9604 and do not establish anything for HGH Fragment 176-191. Check each product's certificate of analysis for exact sequence, disulfide status and mass. If a lot does not match 1,815.09 g/mol, none of the AOD-9604 data apply to it.

At a glance

These dosages are a helpful guide, not a prescription. Every clinician is expected to do their own due diligence before prescribing.

  1. Start

    1 mg once daily, oral capsule (lowest of 5 active arms)1

    Human study

  2. Ceiling

    30 mg once daily, oral capsule (top arm of the 1 to 30 mg trial)1

    Human study
Frequency
Once daily1
Route
Oral capsule1
Course
12 weeks after a 2-week run-in1
All figures are oral AOD-9604 data, a separate product, not HGH Fragment 176-191, and not subcutaneous; they do not transfer to the injectable vial.
Calculate this dose

Dosing detail

Human studies

Human study

  • Healthy adult males, BMI 24-30 kg/m2 (safety, dose escalation); rhGH 0.12 IU/kg IV as positive control

    25 to 400 µg/kg2

    Route
    Intravenous infusion over 20 minutes
    Frequency
    Three single doses plus placebo, each separated by a 7-day washout
    Duration
    Single doses
    n
    15 enrolled, 14 completed
    Design
    Phase I double-blind, placebo-controlled, dose escalation (METAOD001), 2001
    Source quote
    range 25 to 400 µg/kg bodyweight; single IV infusion doses over 20 minutes

    Finding. No serious adverse events. 29 adverse events occurred in 12 subjects across all arms, including the rhGH positive control: headache 6, fatigue 4, hypoglycemia (unspecified) 3, dizziness 3. These were not attributed to dose or treatment. Safety study with no efficacy endpoint. Sponsor-funded.

  • Obese males, BMI >=35 kg/m2 (safety/PD)

    25, 50 and 100 μg/kg2

    Route
    Intravenous infusion over 20 minutes
    Frequency
    Four single doses (three AOD9604 doses plus placebo), 7-day washout
    Duration
    Single doses
    n
    23
    Design
    Phase IIa double-blind, placebo-controlled 4x4 Latin square (METAOD002), 2001
    Source quote
    Each subject received 4 single doses (25, 50 and 100 μg/kg AOD9604 or placebo; single IV infusion doses over 20 minutes), separated by a 7-day washout period.

    Finding. No serious adverse events. Headache was the most common adverse event. Euphoria (5/23) and one chest-tightness event were possibly related. Weight loss did not differ from placebo (FDA summary of Wilding 2004).

  • Obese males, BMI >=35 kg/m2 (safety/PD)

    9, 27 and 54 mg2

    Route
    Oral capsule
    Frequency
    Three increasing single doses or placebo, 2-week washout
    Duration
    Single doses
    n
    17 (15 completed)
    Design
    Phase IIa double-blind, placebo-controlled 4x4 Latin square (METAOD003), 2002
    Source quote
    subsequently received 3 increasing doses of AOD9604 (9, 27 and 54 mg) or placebo. Each dose administration was separated by a 2-week wash-out period.

    Finding. Two serious adverse events at 54 mg: diarrhea (possibly related) and pneumonia (unrelated). Headache, diarrhea and flatulence were most common.

  • Obese males, BMI >=30 kg/m2

    9, 27 or 54 mg2

    Route
    Oral capsule
    Frequency
    Daily for 7 days (times per day not stated for this trial)
    Duration
    7 days
    n
    36 (9 per group)
    Design
    Phase IIa randomized, double-blind, placebo-controlled (METAOD004), 2003
    Source quote
    multiple daily doses (9, 27 or 54 mg AOD9604) administered orally (capsules) for seven days

    Finding. No serious adverse events. Headache, diarrhea and flatulence were more frequent at 54 mg than at 9 mg, 27 mg or placebo.

  • Obese adults (males and females), BMI >=35 kg/m2; efficacy (body weight), safety, tolerability

    1, 5, 10, 20 or 30 mg1

    Route
    Oral capsule
    Frequency
    Once daily
    Duration
    12 weeks after a 2-week run-in
    n
    300 (50 per group)
    Design
    Phase IIb randomized, double-blind, placebo-controlled (METAOD005), 2004; known only from a meeting abstract and the Stier safety summary
    Source quote
    randomized after a 2-week run-in period to receive oral AOD-9604 (1, 5, 10, 20 or 30 mg per day) or placebo for 12 weeks.

    Finding. Abstract: -0.22 kg/week at 1 mg versus -0.07 kg/week with placebo, described as significant for females. Five serious adverse events occurred: basal cell carcinoma, lipoma and squamous cell carcinoma (20 mg), breast cancer (5 mg) and malignant melanoma (10 mg). None occurred at 30 mg. The investigator judged all unrelated and argued there was no dose effect. FDA states relatedness cannot be assessed because case detail was not provided. No peer-reviewed efficacy report exists.

  • Obese adults, BMI 30-45 kg/m2, plus dietician-supervised diet and exercise (OPTIONS study)

    0.25, 0.5 or 1 mg1

    Route
    Oral tablet
    Frequency
    Once daily
    Duration
    24 weeks after a 4-week placebo run-in
    n
    536 enrolled per FDA/ASX (Stier 2013 gives 534), 502 randomized
    Design
    Phase IIb randomized, double-blind, placebo-controlled (METAOD006), 2006; unpublished, reported in a company ASX filing
    Source quote
    Study subjects received oral AOD-9604 (0.25, 0.5, or 1 mg) or placebo once daily in addition to a dietician-supervised diet and exercise program for 24 weeks.

    Finding. No significant weight-loss difference versus placebo at 12 or 24 weeks. The sponsor ended obesity development in February 2007.

Clinical practice

Clinical practice

Practice dosing comes from forums and community pages and has no pharmacokinetic validation. One peer-reviewed review (PMID 42395176) tabulates forum protocols but does not validate them. Human data are oral and IV AOD-9604 (0.25-54 mg/day oral; 25-400 ug/kg IV), not subcutaneous. FDA found no human pharmacokinetic data by any route. Treat these doses as unvalidated.

Start
250 mcg per injection, once daily (community-reported baseline)
Titration
No source states a titration schedule. A community page lists 250 mcg as baseline, 380 mcg and 500 mcg as higher steps, and 500-1000 mcg once daily as a higher-dose option.
Typical
250-500 mcg per injection, 1-2 times daily (community-reported; no primary source)
Ceiling
500-1000 mcg once daily (community-reported upper protocol). The community page attributes this to a '1 mg' trial without citing it. The only 1 mg human data found are the oral 24-week RCT arm, which showed no significant weight loss.
Frequency
Once daily, or twice daily (AM fasted plus pre-bed)
Route
Subcutaneous (community protocols). Human trials used oral (capsule/tablet) and IV only.
Timing
Empty stomach, morning fasted and/or before bed; wait 30 minutes before eating
Cycle
4-8 weeks on, 2-4 weeks off (community page entry); the same page also lists 4-8 and 8-12 week protocols. Peer-reviewed review reports forum cycles of 8-12 weeks.

Sources

  • Clinical practicePeer-reviewed review4
    Bodybuilding-related forums: 250–500 µg/day SC in 2–3 injections, ideally before exercise or at morning (fasted)

What clinics and vendors publish

These ranges come from clinic and vendor publications, not studies.

Community-reported
  • Community-reportedVendor page3
    Common HGH Fragment 176-191 protocol doses centered on the 250 mcg baseline (research range 250 mcg–500 mcg)
  • Community-reportedVendor page3
    Clinical Dose 250-500 mcg per injection Frequency 1-2 times daily Duration 4-8 weeks on, 2-4 weeks off Inject on empty stomach (morning fasted and/or before bed)
  • Community-reportedVendor page3
    Higher Dose Protocol Community Dose 500-1000 mcg Frequency Once daily (AM fasted) Duration 4-8 weeks Route Subcutaneous
  • Community-reportedOther web source1
    Some wellness clinic websites recommend that the peptide is to be injected 30 minutes prior to eating to fully metabolize and achieve optimal results.
  • Community-reportedOther web source1
    One wellness clinic website markets AOD-9604 products as a 600 mcg/ml 10 mL vial and a 1 mg capsule.
  • Community-reportedOther web source1
    Another wellness clinic website markets a product containing AOD-9604 acetate as 250 mcg rapid ODT daily.

Safety

Serious warnings

  • No FDA label exists, so there is no boxed warning.1
  • FDA 503A page: 'Compounded drugs containing AOD-9604 may pose significant risk for immunogenicity for certain routes of administration and may have complexities with regard to peptide-related impurities and API characterization.'5
  • FDA 503A page: 'FDA has also identified serious adverse events that may be associated with AOD-9604, though causality is not clear.' The FDA briefing memo states that a FAERS search through Jan 7, 2024 returned no reports.5
  • Serious adverse events in the 12-week oral trial (METAOD005): basal cell carcinoma, lipoma (benign) and squamous cell carcinoma (20 mg), breast cancer (5 mg), malignant melanoma (10 mg). None occurred at 30 mg. The investigator judged them unrelated. FDA: 'We have concerns about the reports of various cancers reported with the 12-week study of oral AOD-9604 administration; information is insufficient whether these various types of cancers were unrelated to AOD-9604.'1
  • FDA notes that subcutaneous routes are generally associated with greater immunogenicity than IV. No anti-AOD9604 antibodies were found in the oral-trial subsets tested. No subcutaneous human data exist.1
  • FDA: 'We did not find pharmacokinetic/bioavailability information for any route of administration. FDA did not find information on the proposed subcutaneous and transdermal use of AOD-9604 (free base) or AOD-9604 acetate in humans.'1

Contraindications

  • No labeled contraindications exist because the drug is unapproved and has no label. Precautions based on FDA concerns and trial data: active or recent malignancy or a strong cancer history (FDA cancer concern); pregnancy, lactation and pediatric use (no data); known hypersensitivity to the peptide or excipients (immunogenicity risk is higher by the subcutaneous route).1

Adverse effects

  • Oral AOD-9604 trials: headache, diarrhea and flatulence were most commonly reported. Increased appetite and nausea were also listed (METAOD003). Headache, diarrhea and flatulence were more frequent at 54 mg in the 7-day study.1
  • IV AOD-9604: headache was most common (16/23 subjects, mild or moderate). Euphoria occurred in 5/23 (mild or moderate). One severe chest-tightness event at 50 ug/kg (about 4 mg at 80 kg) was deemed possibly related. In METAOD001 (n=15, rhGH positive control), adverse events also included hypoglycemia (unspecified, 3), fatigue (4) and dizziness (3).2
  • 24-week oral trial (0.25-1 mg): the most common adverse event terms were nasopharyngitis, headache, back pain and diarrhea. Events judged probably or possibly related were similar across groups (sponsor-reported; no breakdown published).1

Monitoring

  • Trials monitored vital signs, ECG, hematology, biochemistry, urinalysis, lipids, oral glucose tolerance, serum IGF-1 and anti-AOD9604 antibodies. The sponsor reported no significant IGF-1, glucose tolerance or ECG changes.2
  • Suggested prescriber monitoring (not taken from the trials): baseline and periodic fasting glucose or HbA1c, with counseling on low-glucose symptoms when dosing fasted; IGF-1 at baseline and follow-up as a precaution; age-appropriate cancer screening and skin examination; injection-site and hypersensitivity review. Antibodies were tested only in oral-trial subsets, so there are no subcutaneous immunogenicity data.1

Interactions

  • None studied. Use caution with insulin or antidiabetic drugs and other GH-axis agents, because hypoglycemia was reported in the IV study. This is an inference and has not been tested.1

Handling

Reconstitution

Community guidance: reconstitute the lyophilized powder with bacteriostatic water, inject slowly against the vial wall, swirl gently and do not shake. A 10 mg vial plus 2 mL bacteriostatic water gives 5.00 mg/mL. In the sponsor's IV trials the lyophilized product was reconstituted with sterile water for injection. Request the certificate of analysis with sequence and mass. Grey-market AOD9604 vials have been identified in the USA (PMID 25208511).

Storage before mixing

Community guidance: 2-8C or frozen. FDA memo: the AOD-9604 acetate certificate of analysis specifies 2-8 °C, with -20 °C recommended for storage beyond 6 months.

Storage after mixing

Follow the beyond-use date on the pharmacy label (USP <797>). A community-page range of 14-28 days is not validated.123

Evidence

No human efficacy data exist for '176-191' itself. For the related AOD-9604, six sponsor-run double-blind trials (about 900 subjects, oral and IV) showed good short-term tolerability. The 24-week Phase IIb trial found no significant weight loss versus placebo. The 12-week Phase IIb trial is known only from an abstract. No subcutaneous human data exist. The sponsor ended obesity development in 2007.

Mechanism

AOD-9604 is a synthetic C-terminal fragment of growth hormone (Tyr-hGH 177-191). In rodent and isolated human adipose tissue it increased lipolysis and reduced lipogenesis, reportedly without raising IGF-1 or impairing glucose handling. Controlled human obesity trials found no significant weight-loss benefit over placebo.267

Availability

Amounts offered

  • 10 mg

Custom strengths on request.

References

According to PubMed

  1. 1FDA Briefing Document for AOD-9604 Related Bulk Drug Substances, Pharmacy Compounding Advisory Committee, Dec 4, 2024 (memo dated 11/5/2024)U.S. FDA / CDER, 2024
  2. 2Safety and Tolerability of the Hexadecapeptide AOD9604 in HumansJ Endocrinol Metab 2013;3(1-2):7-15 (not indexed in PubMed; authors employed by or consulting for Metabolic Pharmaceuticals, which funded the six trials), 2013
  3. 3HGH Fragment 176-191 Dosing Calculator, 10 mg vial (community-reported protocols)peptideprotocolwiki.com (community compilation; not a clinical or peer-reviewed source), 2026
  4. 4The emerging landscape of performance-enhancing peptides modulating GH-IGF1 axis: bridging the gap between clinical evidence and patient self-administrationFront Endocrinol (Lausanne) 17:1822475, 2026
  5. 5Certain Bulk Drug Substances for Use in Compounding that May Present Significant Safety Risks (page content current as of 04/22/2026)U.S. FDA, 2026
  6. 6Effects of oral administration of a synthetic fragment of human growth hormone on lipid metabolismAm J Physiol Endocrinol Metab 279(3):E501-7, 2000
  7. 7Molecular and cellular actions of a structural domain of human growth hormone (AOD9401) on lipid metabolism in Zucker fatty ratsJ Mol Endocrinol 25(3):287-98, 2000
  8. 8December 4, 2024 Pharmacy Compounding Advisory Committee Meeting MinutesU.S. FDA, 2024
  9. 9Obesity drugs in clinical developmentCurr Opin Investig Drugs 7(4):312-8, 2006

Last reviewed 2026-10-14. 55 figures checked against their sources. How this works