HGH 191AA
Also known as Somatropin, Human growth hormone, 191 amino acid HGH
Recombinant human growth hormone identical to endogenous pituitary GH.
Medical status: Prescription medicine (somatropin), approved for growth hormone deficiency and a small number of other conditions. Everything else is off-label.
Also commonly used for (off-label)
- Lean mass, strength and body recomposition
- Fat loss, especially stubborn abdominal fat
- Tendon, ligament and joint repair after injury
- Skin quality, sleep depth and mid-life recovery
Off-label and research uses are what people report, not approved indications. Talk to a clinician before using any of them.
How it's taken (route)
a small shot into the fat just under the skin (belly, thigh, or love handle)
New to peptides? Start with the beginner's guide.
- Documented dose
- 330–1330 mcg
- Typical frequency
- Once daily, typically in the morning or split AM/PM (dosed in IU, commonly 1-4 IU per day)
- Cycle
- 24 weeks on, 8 off
- Half-life
- ~20-30 minutes (subcutaneous); IGF-1 elevation lasts 12-24 hours
- Common vial sizes
- 5 mg, 10 mg
- Regulatory status
- Prescription medicine (somatropin) approved for growth hormone deficiency and a small number of other conditions. All other use is off-label, and possession without a prescription is illegal in many countries including the US.
Dose on a U-100 syringe (330–1330 mcg)
| Vial | BAC water | Draw |
|---|---|---|
| 5 mg | 1 mL | 6.6–27 units |
| 5 mg | 1.5 mL | 9.9–40 units |
| 10 mg | 2.5 mL | 8.3–33 units |
| 10 mg | 3 mL | 9.9–40 units |
On a U-100 syringe, 100 units = 1 mL, and the syringe holds 100 units total. Most people keep a single subcutaneous injection under about 50 units — bigger volumes are usually mixed stronger (less water) or split into two shots. Only mixes that fit in one syringe are shown. Always double-check with the reconstitution calculator.
What it does
HGH 191AA is recombinant human growth hormone (somatropin) — a lab-made copy of the exact 191-amino-acid hormone the pituitary produces. Unlike secretagogues such as ipamorelin or CJC-1295, it does not ask your pituitary to do anything; it is the hormone itself, so the effect is stronger and much more dose-dependent. What people look into it for: • Lean mass, strength and body recomposition • Fat loss, particularly stubborn abdominal fat • Tendon, ligament and joint repair after injury • Skin quality, deeper sleep and mid-life recovery It is also the most side-effect-prone compound in this category. Water retention, carpal tunnel and insulin resistance all scale with dose, which is why sensible protocols run low and long rather than high and short. Doses above roughly 4 IU daily bring sharply more side effects for diminishing returns.
Mechanism
HGH binds growth hormone receptors throughout the body, directly stimulating lipolysis and protein synthesis and indirectly raising IGF-1 via the liver. IGF-1 mediates most of its anabolic and tissue-repair effects.
Storage — lyophilisedwhat's this?
Store lyophilized at 2-8C (refrigerated); do not freeze somatropin powder unless the manufacturer specifies it.
Storage — reconstitutedwhat's this?
Refrigerate at 2-8C after reconstitution and use within 14-21 days. HGH is fragile - never shake the vial.
Reconstitution noteswhat's this?
HGH is measured in IU, not mcg: 1 IU is about 333 mcg, so 1 mg is roughly 3 IU and a 15 IU vial holds about 5 mg. Add bacteriostatic water slowly down the vial wall, never straight onto the powder, then roll the vial gently between your palms — shaking denatures the protein. A 10 IU vial with 1 mL gives 1 IU per 10 units on a U-100 syringe (2 IU = 20 units); a 15 IU vial with 1.5 mL gives the same. Most people start at 1–2 IU daily and only move up if it is well tolerated.
Stacks well with
- Testosterone CypionateThe classic recomposition pairing — growth hormone alongside a full androgen base.
- BPC-157Tissue repair support during injury-recovery blocks.
- IpamorelinSome keep a secretagogue running to preserve their own pulsatile release.
Popular combinations reported in the community and research literature — not a recommendation. Adding peptides multiplies side-effect risk; check with a clinician.
Commonly reported side effects
- Water retention and bloating
- Joint or muscle aches
- Carpal tunnel symptoms / numb hands
- Elevated fasting glucose and insulin resistance
- Injection-site reactions
- Headache
- Tiredness in the first weeks
Contraindications noted
- Active malignancy
- Diabetic retinopathy
- Pregnancy or breastfeeding
- Closed growth plates (pediatric use requires specialist oversight)
Research notes
Fasting glucose, HbA1c and IGF-1 are the usual markers to track — IGF-1 is what a clinician uses to judge whether a dose is sensible. "191AA" refers to the full-length, correctly sequenced hormone, as opposed to older 192AA versions; counterfeits and underdosed vials are common on the grey market. Pharmaceutical somatropin is prescription-only in most countries.
Vendors carrying HGH 191AA
These research suppliers list this compound. Prices, vial sizes and testing vary — always check the current lot certificate before you buy.
Peptide Streak does not sell peptides and is not affiliated with these vendors. Some list metabolic compounds under coded product names.