TL;DR: GHRP-6 ships in two sizes on our catalogue, 5mg and 10mg. At PeptiMap’s reference volumes — 2mL for the 5mg vial, 3mL for the 10mg — you get 2.5mg/mL (25 mcg per unit) and 3.33mg/mL (33.3 mcg per unit) respectively. That makes a 100mcg saturation dose 4 units from the small vial and 3 units from the big one. The charts below run 50mcg to 300mcg for both vials at both 2mL and 3mL, and the GHRP-6 calculator will do any volume you prefer. Every unit figure here assumes a U-100 syringe, where 1 unit = 0.01 mL.
The hunger thing is the reason anyone picks GHRP-6
Every GH secretagogue in the family binds the same receptor, GHS-R1a, the one ghrelin itself uses. What separates them is how much of ghrelin’s other behaviour comes along for the ride. GHRP-6 is the one that brings almost all of it.
The appetite response is the single most consistently reported observation in GHRP-6 research models: a strong, unmistakable orexigenic signal that typically shows up within 15 to 30 minutes of administration. That is not a side note to the compound — it is the reason GHRP-6 exists as a distinct research tool. If your study design wants an appetite signal, GHRP-6 gives you one that is reliable enough to build a model around. If your design treats appetite as a confounder, you reach for something else.
Our own comparison piece, GHRP-2 vs GHRP-6, lays out the split in detail: GHRP-2 matches or slightly exceeds GHRP-6 on raw GH release while producing noticeably less hunger, and ipamorelin is the selective option that leaves cortisol, prolactin and appetite closest to baseline. So the practical ordering is: pick GHRP-6 when the ghrelin-like response is the point, not when you are tolerating it.
The half-life figure is real data, not a forum number: Cabrales et al., European Journal of Pharmaceutical Sciences 2013, measured a 2.5 ± 1.1 h elimination half-life in nine healthy male volunteers after a single intravenous bolus, with a distribution half-life of 7.6 minutes. The fast distribution phase is why the GH pulse is brief even though clearance takes hours.
The two formulas behind every number below
The whole chart is these two lines, applied over and over.
mg/mL = vial strength (mg) ÷ BAC water added (mL)
mcg per unit = (mg/mL × 1000) ÷ 100
Worked example, 5mg vial with 2mL — the volume our GHRP-6 5mg page uses as its reference:
- Concentration: 5 ÷ 2 = 2.5 mg/mL = 2500 mcg/mL
- Per unit: 2500 ÷ 100 = 25 mcg per unit
- A 100 mcg draw: 100 ÷ 25 = 4 units = 0.04 mL
Worked example, 10mg vial with 3mL — the reference on our GHRP-6 10mg page:
- Concentration: 10 ÷ 3 = 3.33 mg/mL = 3333 mcg/mL
- Per unit: 3333 ÷ 100 = 33.3 mcg per unit
- The same 100 mcg draw: 100 ÷ 33.3 = 3 units = 0.03 mL
Note what just happened. The bigger vial gives you a smaller number on the syringe for the same dose, because you concentrated it more. The vial label never decides units. Concentration does.
GHRP-6 dosing chart: 5mg vial
Two tables, one per reconstitution volume. Doses per vial assume no waste and full recovery.
5mg vial + 2mL BAC water = 2.5 mg/mL (25 mcg per unit)
| Target dose | Draw volume | U-100 units | Doses per vial |
|---|---|---|---|
| 50 mcg | 0.02 mL | 2 units | 100 |
| 100 mcg | 0.04 mL | 4 units | 50 |
| 150 mcg | 0.06 mL | 6 units | 33.3 |
| 200 mcg | 0.08 mL | 8 units | 25 |
| 250 mcg | 0.10 mL | 10 units | 20 |
| 300 mcg | 0.12 mL | 12 units | 16.7 |
5mg vial + 3mL BAC water = 1.67 mg/mL (16.7 mcg per unit)
| Target dose | Draw volume | U-100 units | Doses per vial |
|---|---|---|---|
| 50 mcg | 0.03 mL | 3 units | 100 |
| 100 mcg | 0.06 mL | 6 units | 50 |
| 150 mcg | 0.09 mL | 9 units | 33.3 |
| 200 mcg | 0.12 mL | 12 units | 25 |
| 250 mcg | 0.15 mL | 15 units | 20 |
| 300 mcg | 0.18 mL | 18 units | 16.7 |
Doses per vial are identical across the two tables, obviously — 5mg is 5mg. All that changed is the ruler. The 3mL version spreads the same doses across 1.5× as many syringe marks, which is the entire argument for using it.
18 units on a U-100 syringe = 0.18 mL = 300 mcg when the vial sits at 1.67 mg/mL. The same dose from the same vial in 2mL is only 12 units.
GHRP-6 dosing chart: 10mg vial
10mg vial + 2mL BAC water = 5 mg/mL (50 mcg per unit)
| Target dose | Draw volume | U-100 units | Doses per vial |
|---|---|---|---|
| 50 mcg | 0.01 mL | 1 unit | 200 |
| 100 mcg | 0.02 mL | 2 units | 100 |
| 150 mcg | 0.03 mL | 3 units | 66.7 |
| 200 mcg | 0.04 mL | 4 units | 50 |
| 250 mcg | 0.05 mL | 5 units | 40 |
| 300 mcg | 0.06 mL | 6 units | 33.3 |
10mg vial + 3mL BAC water = 3.33 mg/mL (33.3 mcg per unit)
| Target dose | Draw volume | U-100 units | Doses per vial |
|---|---|---|---|
| 50 mcg | 0.015 mL | 1.5 units | 200 |
| 100 mcg | 0.03 mL | 3 units | 100 |
| 150 mcg | 0.045 mL | 4.5 units | 66.7 |
| 200 mcg | 0.06 mL | 6 units | 50 |
| 250 mcg | 0.075 mL | 7.5 units | 40 |
| 300 mcg | 0.09 mL | 9 units | 33.3 |
The 10mg vial in 2mL is the tightest configuration on this page, and it shows: a 50mcg dose is a single unit on the barrel. That is not a draw anyone can hit repeatably. It is fine at 200 or 300 mcg, and unusable at the bottom of the range.
Why the chart stops at 300mcg
Because past roughly that point you are paying for peptide that does not turn into GH.
The saturation-dose behaviour is the defining feature of GHRP dosing and it applies across the family. Beyond about 100mcg per administration, each additional microgram delivers progressively less extra GH release, while the off-target signals — cortisol, prolactin, and in GHRP-6’s case appetite — keep climbing in a straight line. Our GHRP-2 dosing protocol guide unpacks the dose-response curve behind this.
The consequence for the tables above is structural: research protocols overwhelmingly split the daily amount into two or three separate administrations near the saturation point rather than stacking one large injection. Three 100mcg doses beat one 300mcg dose on total GH captured, and the 300mcg rows in these charts exist mainly as an upper reference boundary rather than a target.
Run the numbers on a 3× daily, 100mcg schedule — 300 mcg per day — and the vials sort themselves out fast:
- 5mg vial: 5000 ÷ 300 = 16.7 days of coverage
- 10mg vial: 10000 ÷ 300 = 33.3 days of coverage
Our catalogue pages quote reconstituted storage at 2-8 °C for roughly three to six weeks. A 10mg vial at 300 mcg daily runs 33 days, which lands inside the four-to-six-week figure the 10mg page quotes — a clean fit, with a little slack. At 100 mcg once daily, the same vial would need 100 days to empty and most of it would sit past the window. That is the real argument for the 5mg size, and it has nothing to do with price.
What the two sizes cost
Our EU price index lists both GHRP-6 sizes, which is more than we can say for a lot of compounds:
- 5mg at €24.00 → €4.80 per mg
- 10mg at €33.00 → €3.30 per mg
Doubling the vial cuts cost per mg by 31.3%. In absolute terms: two 5mg vials cost €48.00 for the same 10mg that a single 10mg vial delivers for €33.00 — a €15.00 difference for identical peptide.
Per dose, at the 100mcg saturation figure, that is €24.00 ÷ 50 = €0.48 from the 5mg vial against €33.00 ÷ 100 = €0.33 from the 10mg. At three doses a day, roughly €1.44 versus €0.99 daily.
Listed EU price-index figures at the 10mg size: GHRP-6 EUR 33.00, GHRP-2 EUR 33.00, CJC-1295 no DAC EUR 44.99, ipamorelin EUR 54.99.
GHRP-6 and GHRP-2 are priced identically in our snapshot at both sizes, so the choice between them is a pharmacology decision rather than a budget one. Against ipamorelin, GHRP-6 at 10mg is 40% cheaper per mg — the selective compound carries a premium.
One caveat that the retatrutide cost piece makes at length and applies here too: listed cost per mg assumes you use every milligram. A 30-day block at 300 mcg daily needs 9mg. Buy one 10mg vial and your effective cost is €33.00 ÷ 9 = €3.67 per delivered mg, not €3.30, because 1mg stays in the vial. Small effect at these prices, but it is the same arithmetic that gets expensive on a GLP-1.
Hand it to the calculator
None of this needs re-deriving by hand every time the volume changes:
- The reconstitution calculator takes any vial strength, any BAC volume and any target dose, and returns mg/mL, mcg per unit and the syringe mark.
- The GHRP-6 calculator is the same tool pre-loaded with both catalogue sizes.
- The cross-compound reconstitution chart covers the general principle, and the price index holds the figures used above.
For the pairing question — GHRP-6 alongside a GHRH analog such as CJC-1295, where the two receptors are complementary — the common peptide stacks guide is the place to start.
Frequently Asked Questions
How much BAC water do I add to a 10mg GHRP-6 vial?
3mL is our catalogue reference, giving 3.33 mg/mL and 33.3 mcg per unit, so a 100mcg dose is 3 units. Using 2mL instead concentrates it to 5 mg/mL and makes the same dose 2 units — compact, but hard to read accurately at doses under 150mcg.
How many units is 100mcg of GHRP-6?
It depends entirely on concentration. At 2.5 mg/mL (5mg in 2mL) it is 4 units. At 1.67 mg/mL (5mg in 3mL) it is 6 units. At 3.33 mg/mL (10mg in 3mL) it is 3 units, and at 5 mg/mL (10mg in 2mL) it is 2 units. The vial label tells you nothing on its own.
What is the GHRP-6 saturation dose?
Around 100mcg per administration, the same figure the wider GHRP literature uses. Past it, extra micrograms produce steeply diminishing GH return while appetite and cortisol responses keep rising — which is why protocols favour two or three moderate doses across the day over one large one.
Why does GHRP-6 cause so much hunger?
Because it tracks ghrelin’s binding behaviour more closely than its siblings do. The GHS-R1a receptor drives both GH release and appetite, and GHRP-6 activates the appetite arm strongly — typically within 15 to 30 minutes. GHRP-2 releases comparable GH with much less of it, and ipamorelin less again.
Which GHRP-6 vial size should I choose?
Match it to the reconstituted window rather than the price. At 300 mcg daily a 10mg vial runs 33 days, inside the four-to-six-week refrigerated window that page quotes; at 100 mcg daily it would take 100 days to empty, so the 5mg vial is the sensible size for low-frequency work.
Is the 10mg GHRP-6 vial cheaper per mg?
Yes, by 31.3% in our price index: €4.80 per mg at 5mg against €3.30 per mg at 10mg. Two 5mg vials cost €48.00 for the same peptide a single 10mg vial delivers at €33.00.
References
- Cabrales A, Gil J, Fernández E, et al. “Pharmacokinetic study of Growth Hormone-Releasing Peptide 6 (GHRP-6) in nine male healthy volunteers.” European Journal of Pharmaceutical Sciences, 2013;48(1-2):40-46. doi:10.1016/j.ejps.2012.10.006.
- Bowers CY, Momany FA, Reynolds GA, Hong A. “On the in vitro and in vivo activity of a new synthetic hexapeptide that acts on the pituitary to specifically release growth hormone.” Endocrinology, 1984;114(5):1537-1545.
- Pandya N, DeMott-Friberg R, Bowers CY, Barkan AL, Jaffe CA. “Growth hormone (GH)-releasing peptide-6 requires endogenous hypothalamic GH-releasing hormone for maximal GH stimulation.” Journal of Clinical Endocrinology and Metabolism, 1998;83(4):1186-1189.
- Laferrère B, Abraham C, Russell CD, Bowers CY. “Growth hormone releasing peptide-2 (GHRP-2), like ghrelin, increases food intake in healthy men.” Journal of Clinical Endocrinology and Metabolism, 2005;90(2):611-614.
- PeptiMap. “EU Peptide Price Index” — build-time snapshot of listed European research-supply pricing. The €24.00 and €33.00 figures above come from that dataset, not from published literature.
This article is a research and educational reference only; GHRP-6 is not an approved medicine, this is not medical advice, and it is not for human consumption.