# GHRP-6

First-generation GHRP used as an appetite drug for bulking; strong hunger, cortisol, glucose, GH axis.

- Page: https://peprank.xyz/peptides/ghrp-6
- Category: Hormones & libido (Research peptide)
- Also known as: growth hormone-releasing hexapeptide; CIGB-500 (Cuban development code)
- Routes: Injection
- Safety tier: Strict: Avoid · Balanced: Caution · Evidence only: Caution
- Risk axes (0 none to 3 severe): Seen harm 0, Mechanism 2, Data gap 2, Silent harm 3, Product 3
- Positive: 59% of 14 graded reports glowing or positive, shrunk toward the 49% all-report average by 8 reports' weight
- Rank: #25 of 61 research peptides
- Graded reports: 14 (Glowing 1, Positive 8, Mixed 2, Nothing 2, Negative 1)
- Evidence: Small human studies — Pharmacology only (infusion, pharmacokinetic and single-dose phase I studies of 9-18 men); developed in Cuba for heart-attack cardioprotection, never approved
- Access: Grey market
- Onset: Hunger within 10-20 minutes of a subq shot; GH peaks within the hour.
- Lasts: Elimination half-life about 2.5 hours; the appetite push lasts 1-2 hours, so users dose before each target meal.
- Cost per month: ≈ €13–81 (researchers' estimate)
- Updated: 2026-10-30

**Why Avoid under the strict bar:** GH/IGF-1 axis elevation plus cortisol rise and reduced insulin sensitivity (FDA), with only single-dose human safety data.

## What users report

Fourteen reports, almost all from people using it to gain weight. The hunger spike is the reliable effect: within 10-20 minutes at 200 mcg, with users eating 500-800 extra kcal and reporting 8 lb in 4-6 weeks (one claims 48 to 67 kg). It is weaker or absent at 100-150 mcg for some, and two very lean users felt no appetite change at all. Side effects are transient nausea, flushing and heavy sweating after fasted shots; one long-time user says it wrecks his sleep. Lifters compare it unfavourably with ipamorelin for anything but appetite. Felt nothing: 2 of 14 reports felt no appetite effect (at 150-200 mcg), and one more says the effect faded after two weeks..

**Effects:** strong hunger within 10-20 minutes; weight gain when used for bulking; faster gastric emptying; acute GH and IGF-1 rise

**Downsides:** nausea, flushing and sweating for 10-15 minutes after injection; heavy sweating and overheating when injected fasted; sleep disruption for some; effect fades within weeks for some users

**Risks:** GH/IGF-1 axis elevation (glucose, theoretical neoplasm promotion); FDA category 2 (2023): potential cortisol effect and raised blood glucose from reduced insulin sensitivity; Not GH-selective: FDA notes a cortisol effect, and its super-analogues GHRP-2 and hexarelin raise prolactin and ACTH too; Grey-market vials: aggregation and impurity immunogenicity concerns (FDA)

**Caveat:** The appetite effect is the only one users reliably notice; muscle and fat-loss claims rest on the GH rise, not on outcome data. Human data stop at single IV doses and day-long infusions in healthy young men.

**Typical use:** Users: 100-200 mcg subq 2-3x/day, 20-30 minutes before meals, on an empty stomach; some titrate to 300 mcg. Trials used 1 mcg/kg IV boluses or infusions.

**Getting it:** Research-peptide vials and kits; also in 'Triple G' blends. Never approved; FDA put it in compounding category 2 (503B) in 2023; WADA-prohibited.

**Stacked with:** CJC-1295 / mod-GRF(1-29) (Paired for a larger GH pulse, usually before meals.); MK-677 (Combined by people chasing more appetite; both act on the ghrelin receptor and both raise glucose.); Retatrutide (Used by some on GLP-1/triple agonists who want weight maintenance or gain rather than loss.)

## Risk profile

- **Seen harm 0/3:** No published case reports, label warnings or trial SAE signals: an 18-man single-dose escalation to 400 mcg/kg IV had 23 mild adverse events and none serious, and a 9-man pharmacokinetic study reported none. FDA's 2023 note lists only cortisol and glucose effects, not events. Reddit reports are transient nausea, flushing, sweating and poor sleep. The zero reflects how little documented exposure there is, despite decades of bodybuilding use, not reassurance.
- **Mechanism 2/3:** Hormone-axis activation: a 34-hour infusion doubled GH output and raised IGF-1 by about a quarter, and FDA cites a cortisol effect and reduced insulin sensitivity. Its super-analogues GHRP-2 and hexarelin also release prolactin and ACTH. The IGF-1 cancer association is epidemiological, with no in-vivo demonstration of harm from GHRP-6, so 2.
- **Data gap 2/3:** Never approved. Human data are small pharmacology studies of 9-18 healthy young men given single IV doses or a day-long infusion; there are no repeated-dose trials of the subcutaneous use people actually do.
- **Silent harm 3/3:** The feared harms are theoretical IGF-1-driven tumour promotion (3 under the rubric) and creeping insulin resistance that only shows on glucose or HbA1c testing (a 2). The hunger, sweating and flushing users notice are immediate but not the concern.
- **Product 3/3:** Bought as grey-market injectable vials or cheap 10-vial kits, reconstituted at home and injected 2-3 times a day. FDA flags aggregation and impurity immunogenicity for compounded GHRP-6.
- **Never if:** Pregnancy or breastfeeding (no human reproductive data); Active or past cancer; Diabetes, prediabetes or insulin resistance; Pituitary tumours, including prolactinoma; Cushing's syndrome or other cortisol excess; Current or past eating disorder (used specifically to force hunger); Under 18

## Top reports

- Glowing, metabolic, 100 mcg 2x/day, 20 minutes before meals: “Woog ook 48kg weeg nu 67kg deed 2 keer per dag spuiten 100 mcg per keer 20 min voor het eten” — [r/Biohacking](https://www.reddit.com/r/Biohacking/comments/1w95kxq/ghrp6_cycle_for_strict_weight_gain/19rnktgurp143/)
- Positive, metabolic: “I've had a prescription for it for years. Works well IMO. Doesn't really contribute to gains as much as keep you lean.” — [r/bodybuilding](https://www.reddit.com/r/bodybuilding/comments/19k7eu/ghrp6_i_was_offered_some_at_my_gym_what_do_i_do/c8oscs3/)
- Positive, metabolic: “Ive used it in the past and it allowed me to eat, pin, wait about an hour and i could shove food again, it also forces the stomach to flush down the food faster” — [r/Peptidesource](https://www.reddit.com/r/Peptidesource/comments/1qjczth/ghrp_6_for_a_skinny_guy/o0yatlm/)
- Positive, metabolic, 200 mcg before breakfast: “I inject 200mcg and within 10 minutes I am ready to eat literally anything that is in front of me, it works very well. I haven’t dealt with any side effects other than nausea, sweating, and flushing roughly 5 minutes after injecting but it goes away within 10-15 minutes.” — [r/Biohacking](https://www.reddit.com/r/Biohacking/comments/1w95kxq/ghrp6_cycle_for_strict_weight_gain/pfa0lsz/)
- Positive, metabolic, 100 then 200 mcg: “I started with 100mcg, didnt feel too much made me a little hungry but nothing crazy. I upped to 200mcg and thats when i started to notice very intense hunger.” — [r/Biohacking](https://www.reddit.com/r/Biohacking/comments/1w95kxq/ghrp6_cycle_for_strict_weight_gain/phbm4dx/)

## Studies

- [Jaffe et al. 1993: prolonged GHRP-6 infusion and pulsatile GH secretion in normal men](https://pubmed.ncbi.nlm.nih.gov/7903313/) (controlled, n=9, 1993): A 34-hour IV infusion roughly doubled integrated GH and raised IGF-1 from 252 to 312 mcg/L versus saline; the pituitary stayed responsive throughout.
- [Cabrales et al. 2013: pharmacokinetics of GHRP-6 in nine healthy men](https://pubmed.ncbi.nlm.nih.gov/23099431/) (open-label, n=9, 2013): Single IV doses of 100-400 mcg/kg had an elimination half-life of about 2.5 hours, with exposure rising in proportion to dose.
- [Selman-Housein et al. 2014: clinical safety of GHRP-6 (CIGB-500) in healthy volunteers](https://www.medigraphic.com/cgi-bin/new/resumenI.cgi?IDARTICULO=50887) (open-label, n=18, 2014): Uncontrolled single-dose escalation to 400 mcg/kg IV: 23 mild adverse events in 12 of 18 men, none serious.
- [Berlanga-Acosta et al. 2017: synthetic GHRPs, a historical appraisal of cytoprotective effects](https://pmc.ncbi.nlm.nih.gov/articles/PMC5392015/) (review, 2017): Reviews mostly animal evidence that GHRP-6 protects heart, liver and other tissues from ischaemic injury, the rationale for the Cuban development programme.

## Sources

- [FDA category 2 bulk substances: GHRP-6, added 29 Sep 2023 (cortisol, glucose, immunogenicity)](https://www.fda.gov/drugs/human-drug-compounding/certain-bulk-drug-substances-use-compounding-may-present-significant-safety-risks)
- [WADA 2026 Prohibited List, S2.2.4 (GHRP-6)](https://www.wada-ama.org/sites/default/files/2025-09/2026list_en_final_clean_september_2025.pdf)
- [Renehan et al. 2004: circulating IGF-I and cancer risk, systematic review and meta-regression](https://pubmed.ncbi.nlm.nih.gov/15110491/)
- [Arvat et al. 1997: GHRP-2 and hexarelin (GHRP-6 super-analogues) raise prolactin, ACTH and cortisol in man](https://pubmed.ncbi.nlm.nih.gov/9285939/)