PepRank

GHRP-6

59%positive14 reports

Also: growth hormone-releasing hexapeptide · CIGB-500 (Cuban development code)

ExcludedMetabolicRecoveryInjection

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

#25 of 61 research peptides · updated
Access
Grey market
Cost / month
≈ €13–81
researchers' estimate; no listing to price
InjectionFelt in 10–20 min, lasts 1–2 h
14 user reports
Glowing 1Positive 8Mixed 2Nothing 2Negative 1

  • r/Biohacking· · 1 upvotesOriginal ↗

    Woog ook 48kg weeg nu 67kg deed 2 keer per dag spuiten 100 mcg per keer 20 min voor het eten

    GlowingMetabolic · 100 mcg 2x/day, 20 minutes before meals · Injection

    Dutch-language comment; duration and training not stated

  • r/bodybuilding· · 2 upvotesOriginal ↗

    I've had a prescription for it for years. Works well IMO. Doesn't really contribute to gains as much as keep you lean.

    PositiveMetabolic · Injection · years

    says it was prescribed

  • r/Biohacking· · 1 upvotesOriginal ↗

    I took like 150mcg and didn’t get hungry

    NothingMetabolic · 150 mcg · Injection

Strict case
GH/IGF-1 axis elevation plus cortisol rise and reduced insulin sensitivity (FDA), with only single-dose human safety data.
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..
Best 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
Watch
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)
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
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.

User reports 14

  • r/Biohacking· · 1 upvotesOriginal ↗

    Woog ook 48kg weeg nu 67kg deed 2 keer per dag spuiten 100 mcg per keer 20 min voor het eten

    GlowingMetabolic · 100 mcg 2x/day, 20 minutes before meals · Injection

    Dutch-language comment; duration and training not stated

  • r/bodybuilding· · 2 upvotesOriginal ↗

    I've had a prescription for it for years. Works well IMO. Doesn't really contribute to gains as much as keep you lean.

    PositiveMetabolic · Injection · years

    says it was prescribed

  • r/Peptidesource· · 2 upvotesOriginal ↗

    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

    PositiveMetabolic · Injection

    warns against relying on it instead of fixing diet

  • r/Biohacking· · 1 upvotesOriginal ↗

    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.

    PositiveMetabolic · 200 mcg before breakfast · Injection · 6 weeks

    no morning appetite, using it to bulk

  • r/Biohacking· · 1 upvotesOriginal ↗

    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.

    PositiveMetabolic · 100 then 200 mcg · Injection

  • r/Biohacking· · 1 upvotesOriginal ↗

    Can confirm the hunger spike. Literally 20 minutes. As long as you control yourself to eat the right kinds of food, it’ll help a ton. Besides appetite recovery was noticeably better.

    PositiveMetabolic · Injection

    unsure how much of the recovery was the extra food

  • r/Biohacking· · 1 upvotesOriginal ↗

    every morning id eat, shower and then inject, after injection i would eat another 500-800 calories of food. It definitely helps with high calorie bulks for sure

    PositiveMetabolic · Injection · about 5 weeks

    high-calorie bulk

  • r/Biohacking· · 1 upvotesOriginal ↗

    Been on GHRP-6 and NAD+ for 4 weeks. Having great results as I’ve gained 8lbs.

    PositiveMetabolic · Injection · 4 weeks

    taken with NAD+

  • r/BodyHackGuide· · 1 upvotesOriginal ↗

    It’s amazing at building weight but only if you do it consistently

    PositiveMetabolic · Injection

  • r/BodyHackGuide· · 1 upvotesOriginal ↗

    The ghrp binds, the effects fade 2 weeks in cycle.

    MixedMetabolic · Injection

    62 kg, using it to gain mass

  • r/BodyHackGuide· · 1 upvotesOriginal ↗

    for me when I inject fasted especially in the morning, I break out in this crazy sweat and my body temp goes crazy so try to eat when you wake up then inject like a hour later.

    MixedMetabolic · titrating toward 200-300 mcg · Injection

  • r/Biohacking· · 1 upvotesOriginal ↗

    I took like 150mcg and didn’t get hungry

    NothingMetabolic · 150 mcg · Injection

  • r/SARMsTalk· · 1 upvotesOriginal ↗

    Ghrp-6 by itself at doses ranging 50-200mcg did not increase my appetite. It only moderately reduced satiety. Minor flushing gastric motility etc.

    NothingMetabolic · 50-200 mcg · Injection

    very lean (<10% body fat); MK-677 later worked at 10 mg

  • r/bodybuilding· · 1 upvotesOriginal ↗

    GHRP-6 fucks my sleep up. Ipa does not.

    NegativeSleep · Injection

    ipamorelin did not do this; same result from a second supplier

Safety

Tier by safety barStrict ExcludedBalanced CautionEvidence only Caution

Seen harmMechanismData gapSilent harmProduct

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. Selman-Housein et al. 2014: phase I safety of GHRP-6 (CIGB-500) in 18 healthy men ↗Cabrales et al. 2013: GHRP-6 pharmacokinetics in nine healthy men ↗FDA category 2 bulk substances: GHRP-6 ↗
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. Jaffe et al. 1993: prolonged GHRP-6 infusion raises GH and IGF-1 ↗FDA category 2 bulk substances: GHRP-6 (cortisol, glucose) ↗Renehan et al. 2004: IGF-I and cancer risk (Lancet) ↗
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. Selman-Housein et al. 2014: phase I, 18 men, single doses ↗Jaffe et al. 1993: 34-hour infusion in nine men ↗
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. Renehan et al. 2004: IGF-I and cancer risk ↗
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. FDA category 2 bulk substances: GHRP-6 (immunogenicity) ↗Mendias & Awan 2026 preprint: grey-market peptide quality ↗
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

Studies 4

Sources 4

More in Hormones & libido all 12 →

  1. 1Kisspeptin YNWNSFGLRF (10 residues) Excluded Nasal / Injection≈ €4.1–12 / month52%positive30 reportsTop-of-axis GnRH stimulator for libido/testosterone; chronic use can crash the axis.Directly manipulates the HPG axis; continuous or long-acting exposure suppresses it.
  2. 2Hexarelin Excluded Injection≈ €27–110 / month45%positive5 reportsMost potent GHRP; fast desensitisation, acute cortisol/prolactin rise and direct CD36 heart effects.GH/IGF-1 axis elevation, acute cortisol and prolactin release, and GH-independent actions on heart and coronary vessels via CD36.
  3. 3IGF-1 DES Excluded Injection≈ €22–180 / month49%positive4 reportsShort-acting, truncated IGF-1 injected into the trained muscle; very potent at dropping blood sugar.An IGF-1 receptor agonist about ten times as potent as IGF-1 in cells and the most hypoglycaemic of the IGF-1 variants in primates, with no human data, the same tumour-promotion concern as LR3, and grey-market vials that are rarely tested.
  4. 4MK-677 Excluded Oral≈ €18–54 / month48%positive29 reportsOral GH secretagogue (not a peptide); hunger, bloat, insulin resistance, CHF signal.GH/IGF-1 elevation, insulin resistance and a CHF safety signal in an RCT.
  5. 5Follistatin-344 Excluded Injection≈ €180–450 / month44%positive10 reportsMyostatin/activin-binding protein sold as 1 mg vials; about half of tested vials held no follistatin.Blocks myostatin and activin signalling (FSH axis, angiogenesis, glucose) with no human safety data for the injected protein; vials often hold other drugs.
  6. 6IGF-1 LR3 Excluded Injection≈ €36–140 / month40%positive24 reportsLong-acting IGF-1 analogue (a cell-culture reagent) for muscle; hypoglycaemia, tumour-growth signal.A potent, long-acting IGF-1 receptor agonist with no human data at all: it accelerated tumour growth in mice, the same receptor causes hypoglycaemic seizures and carries a malignancy warning on the approved IGF-1 drug, and every vial is grey-market.
  7. 7Sermorelin YADAIFTNSYRKVLGQLSARKLLQDIMSR (29 residues) Excluded Sublingual / Injection≈ €38–94 / month46%positive29 reportsShort GHRH analogue; cheap, gentle, sleep-focused, still GH/IGF-1 axis.GH/IGF-1 axis elevation, though the mildest of the class.
  8. 8PT-141 DHFRWK (6 residues) Excluded Nasal / Injection≈ €24–170 / month39%positive30 reportsFDA-approved melanocortin libido drug; works strongly for many, raises blood pressure.Cardiovascular effects (BP spikes; contraindicated in CVD) and melanocortin pigmentation effects.
  9. 9GHRP-2 Excluded Injection / Nasal / IV≈ €18–45 / month39%positive7 reportsJapan-approved GH diagnostic sold as a vial; hunger, cortisol and prolactin spikes, GH axis.GH/IGF-1 axis elevation with cortisol and prolactin spikes; FDA notes raised insulin needs and deaths in critically ill subjects.
  10. 10Ipamorelin Excluded Injection≈ €11–100 / month42%positive51 reportsSelective ghrelin-receptor GH secretagogue; sleep and recovery, GH axis plus reactions.GH/IGF-1 axis elevation plus repeated anaphylaxis reports, including a coroner-attributed death.
  11. 11CJC-1295 YADAIFTQSYRKVLAQLSARKLLQDILSR (29 residues) Excluded Injection≈ €14–27 / month38%positive29 reportsLong-acting GHRH analogue stacked with ipamorelin; GH axis, vasodilatory reactions.GH/IGF-1 axis elevation plus FDA-noted tachycardia/vasodilatory reactions and anaphylaxis.

Sequence beads

Each bead is one amino acid in the peptide's chain, coloured by its side chain: grey for non-polar, cyan for polar, blue for positively charged and fuchsia for negatively charged. Length and mix tell related peptides apart at a glance, from a two-residue dipeptide like carnosine to a 43-residue protein like thymosin beta-4. The colours describe chemistry only and predict neither effect nor safety.

non-polarpolarpositivenegative

Report grades

Every first-hand Reddit or X report is graded on its own, from glowing through positive, mixed, nothing and negative to bad reaction, and the bar shows how those grades split. Posts that look vendor-adjacent stay on the peptide's page but are left out of the counts.

GlowingPositiveMixedNothingNegativeBad reaction

% positive

The share of a peptide's graded Reddit and X reports that are glowing or positive, vendor-adjacent posts left out. A peptide with few reports is pulled toward the average of all reports, as if it had eight average ones besides its own, so two glowing posts cannot top the list. Kept peptides rank by the same reports' mean grade, shrunk the same way, and excluded ones follow in that order.

Researcher estimate

No first-hand report of this peptide has been graded yet, so the figure is the researchers' own rating out of 10 from what they read about it. It ranks alongside the computed scores until reports arrive.

Safety tier

Each peptide is tiered clean, caution or excluded from its five risk axes under the chosen safety bar. An excluded peptide has a plausible route to serious harm, so it stays listed with the reason but ranks behind every other entry, however good its reviews.

Safety bar

The safety bar sets how much risk it takes to exclude a peptide. Strict: out on any serious mechanism with little human data, or any documented serious harm. Balanced: out on documented serious harm (unless it is obvious, reversible and from a regulated product), or a serious mechanism whose harm would be silent with no human data at all. Evidence only: out only on documented serious harm in humans that is lasting, delayed or from grey-market product.

Seen harm

Documented serious adverse events in humans, from 0 for none despite real exposure to 3 for deaths or several well-documented serious harms. Serious means a hospital or emergency visit or harm lasting weeks, so a headache or a bad night does not count.

Mechanism

A plausible biological route to serious harm at the doses people use, such as growth-factor signalling, hormone-axis suppression, heart or blood-pressure effects or immune activation. It runs from 0 when none is known to 3 when a dangerous pathway has been shown in living animals.

Data gap

How little human safety data exists for the molecule actually sold, from 0 for an approved drug with large trials and years of use to 3 for no human safety data at all. A modified analogue does not inherit its parent's trials.

Silent harm

Whether the feared harm would show quickly or stay hidden, from 0 when it is obvious and goes on stopping to 3 when it is silent and delayed, like tumour promotion or slow organ damage. User reports cannot reveal a harm that takes years to appear, so a high score here limits what good reviews can tell you.

Product

The risk of what people actually buy, from 0 for a regulated pharmacy or supplement product taken by mouth or on the skin to 3 for a grey-market injectable. In one dataset of 6,441 grey-market samples, 42–71% failed basic quality criteria and 15% carried endotoxin.

Evidence

The strongest kind of study behind the peptide's effects, from an approved drug through human controlled trials and small human studies to animal work or nothing of its own. Animal results often fail to carry over to people.

Access

How people get it: as an approved drug, a compounded prescription, an over-the-counter supplement or from the grey market, where nobody checks the vial. The channel decides both the legal position and the risk of a bad batch.

Price per month

Thirty days of the typical dose, from its low end to its high end, priced at the listing a careful buyer would choose: in stock, from a shop scoring 4 of 5 on trust (third-party tested where no score is set), failing that 3, a pure pack before a blend, a European shop first, then the cheapest per mg. The range is the dose's, not the shops'. A per-dose amount counts once a day unless the dose says otherwise. Prices are in euros at ECB rates of 2026-10-29, before shipping; the shop table keeps each listing's price per mg, per gram for bulk supplements. Where no listing can be priced the researchers' own estimate stands in, and says so.

Dose users report

The middle half of the daily doses stated in at least five first-hand reports, vendor posts left out. Where its middle sits more than twice above or below the declared dose, the month is priced at it as well, since what people take is what they pay for.

Testing

Whether the shop publishes lab results: third-party tested means an independent lab checks each batch, own COA means the shop's own certificate of analysis, and no public tests means neither. A certificate shows purity, not safety.

Added peptide

Some packs sold under one peptide's name hold a second one, such as 5 mg GHK-Cu in a nasal kit, stated only in the description. Sprayed in the nose or injected it reaches the blood like an injection, so it carries the risk of that route and is tiered as the injectable form, whatever its tier on the skin. A pack whose page gives no contents list may hold more than its name.