HGH Fragment 176-191

Quickstart highlights

Dosing & reconstitution guide

Standard protocol (2 mL = 2,5 mg/mL)

A 5 mg vial dissolved in 2 mL bacteriostatic water gives a concentration of 2,5 mg/mL. Calculate your own dilution →

Reconstitution steps

1. Let the vial reach room temperature and wash your hands.
2. Disinfect both rubber stoppers with an alcohol swab.
3. Draw up 2 mL of bacteriostatic water.
4. Inject the water slowly down the glass wall, not directly onto the powder.
5. Swirl gently until clear — never shake.
6. Label the vial with date and concentration and refrigerate.

Supplies needed

• HGH Fragment 176-191 vial (5 mg)
• Bacteriostatic water
• Mixing syringe (1–3 mL) and U-100 insulin syringes
• Alcohol swabs and sharps container

Protocol overview

Dosing protocol in research

Values as described in literature and research protocols; not dosing advice.

Storage instructions

• Lyophilised (powder): cool, dry and dark; long-term at −20 °C.
• After reconstitution: refrigerator at 2–8 °C, use within ~4 weeks.
• Avoid repeated freezing and thawing.

Important notes

How this works

HGH Fragment 176-191 is a small peptide comprising the last 16 amino acids of the human growth hormone molecule. Researchers isolated this specific region because it appears to drive the hormone's effects on adipose tissue. Unlike full-length hGH, this fragment is not studied for growth, but as a tool for metabolic research.

This fragment mimics the way natural growth hormone regulates fat metabolism. It stimulates lipolysis, the breakdown of fats, and inhibits lipogenesis, the formation of new fatty acids. Since the domains responsible for growth and insulin interaction are absent, it does not affect blood sugar levels or IGF-1 concentrations. The peptide acts locally on adipocytes without triggering the systemic growth responses of the full molecule. Its half-life is very short, often requiring multiple daily administrations in laboratory settings. The variant AOD9604 is a stabilized version of this fragment with an added tyrosine residue.

Early animal studies in obese mice demonstrated a significant reduction in body fat. However, human trials on the related compound AOD9604 showed inconsistent results regarding weight loss in humans. The peptide is included on the WADA prohibited list under the category of non-approved substances (S0). It has no official medical approval for human use. Open scientific questions focus primarily on bioavailability and long-term effectiveness. Currently, it remains a research chemical for preclinical studies.

Potential benefits & side effects

Effects described in research

• Stimulation of lipolysis (animal studies)
• Inhibition of lipogenesis

Common side effects

• Injection-site redness
• Headache

Clinical research on AOD9604 reported side effects such as headaches, redness, and irritation at the injection site. There are no indications of negative effects on glucose tolerance, which is a known risk with full-length growth hormone. The safety of long-term use in humans has not been established due to a lack of long-term publications.

Contraindications

• Pregnancy or breastfeeding
• Active or prior cancer
• Under 18 years of age

Lifestyle factors

• Administration on an empty stomach (2 h after / 30 min before food) is most often described.
• Carbohydrates and fat around administration blunt the GH pulse.
• Keep a log of doses, timing and observed effects.
• Adequate sleep, hydration and a stable diet.

Injection technique

• Choose a site with subcutaneous fat: abdomen (5 cm from the navel), thigh or back of upper arm.
• Disinfect, pinch a skin fold and insert at a 45–90° angle.
• Inject slowly, wait 5 seconds and withdraw.
• Rotate sites and use each needle once.

Recommended source

Quality varies widely between suppliers. Look for an independent HPLC/MS lab report per batch, purity ≥ 98% and clear storage and shipping conditions.

As a reference we use the HGH Fragment 176-191 from PeptideWinkel, which publishes lab reports per batch.

Frequently asked questions