Dosing Protocols and Best Practices for Peptide Use

How dose and response relate

Lifters are used to a roughly straight-line rule from training: add load, get stronger. Drug dose-response curves usually bend instead, so extra drug adds less and less effect while side effects keep climbing. For most research peptides, nobody has measured where that bend sits in people.

Community guides answer it for growth hormone releasing peptides (GHRPs) with a "saturation dose" of about 1 mcg/kg, usually rounded to 100 mcg. The claim is that the pituitary's receptors are mostly occupied at that dose, so anything above it is wasted. The idea traces back to early human studies that tested doses around 1 mcg/kg. Read closely, those studies don't show a ceiling there.

What the 1990 GHRP-6 study found

In 1990, Bowers and colleagues gave 18 healthy men GHRP-6 as a single intravenous injection at 0.1, 0.3 or 1.0 mcg/kg. Mean peak growth hormone (GH) rose at each step: about 7.6, 16.5 and 68.7 mcg/L, against 1.2 mcg/L on placebo. The response was still rising steeply at 1.0 mcg/kg, which was the highest dose tested, so the study can't show a plateau at all. It did show a cost at the top dose: prolactin and cortisol roughly doubled at 1.0 mcg/kg and didn't change at the lower doses.

Later studies went higher. In a 1994 study of hexarelin, a related GHRP, in 12 young volunteers, raising the IV dose from 1 to 2 mcg/kg increased total GH output by about 40% (area under the curve about 3,175 vs 4,422). Subcutaneous doses of 1.5 and 3 mcg/kg also gave a dose-dependent rise. For ipamorelin, FDA's 2024 advisory committee review describes a dose-escalation study in 48 healthy men in which GH release rose in line with dose across IV infusions of 4.21-140.45 nmol/kg.

So the human data we found point to diminishing returns at higher doses (the hexarelin curve was flattening), not a hard saturation point at 1 mcg/kg. These were single IV or weight-based doses in small groups of healthy men, with GH measured over a few hours. Users describe fixed subcutaneous doses taken daily for weeks.

Why timing gets so much attention

GH is released in bursts rather than a steady stream, a pattern called pulsatile release. Between bursts, somatostatin from the hypothalamus holds secretion down. In a 1968 study that sampled blood every 30 minutes overnight in eight young adults, the largest GH peak of the night appeared at the onset of deep sleep. When sleep onset was delayed, the peak moved with it.

That finding is the reasoning behind the bedtime timing many users describe for GHRPs and short-acting GHRH analogs such as Mod GRF 1-29 (CJC-1295 without DAC). It also explains the common practice of splitting a daily amount into smaller injections to create separate pulses. The logic is plausible, but as of October 2026 we found no human study comparing bedtime with daytime dosing, or split with single dosing, for any of these peptides. The same goes for the empty-stomach advice in most guides.

Pulsatility also comes up with CJC-1295 with DAC, which binds to albumin and lasts about a week. An earlier version of this page said it replaces pulses with a constant GH "bleed." The human data don't support that. In a 2006 study, healthy men aged 20-40 got a single 60 or 90 mcg/kg dose, and overnight blood sampling a week later found the frequency and size of GH pulses unchanged. What rose was the baseline between pulses: trough GH went up about 7.5-fold and mean GH about 46%. Whether that higher trough matters for results or side effects hasn't been studied. How a peptide's half-life shapes dosing schedules is covered in our page on half-life and dosing schedules.

The case for pairing a GHRH analog with a GHRP

The two classes reach the pituitary through different receptors. GHRH analogs act on the GHRH receptor, while GHRPs act on the ghrelin receptor and also counter somatostatin's brake on release. Our growth hormone pathway explainer covers the receptor biology.

The 1990 Bowers study is the main human evidence for combining them. GHRP-6 at 0.1 or 0.3 mcg/kg, given together with 1 mcg/kg of GHRH, released more GH than either did alone, and the authors described the effect as synergistic. A 1994 study gave hexarelin and GHRH (2 mcg/kg each, IV) to young and elderly men, and the combination released more GH than hexarelin alone in both groups, though less in the older men.

As of October 2026, we found no controlled human trial of the pairing users describe most often, Mod GRF 1-29 with ipamorelin, and no trial of any GHRH-GHRP pairing that measured body composition. The stacking rationale rests on short-term hormone measurements and user reports.

Reported doses, by source

Trial doses and community doses for the same peptide are often very different, so the table keeps them apart. None of these figures is a recommendation.

Two claims from older guides, including this page, need correcting. Many users inject BPC-157 near the injury site, but the animal studies mostly used systemic routes and still reported effects in tendon and muscle; no human study has compared injection sites. For AOD-9604, advice to inject 30-60 minutes before food comes from vendor and clinic guides, and no human trial has tested the injected form at all.

Reconstitution and handling, as reported

Most research peptides ship as lyophilized (freeze-dried) powder. Vendor and community guides describe reconstitution with bacteriostatic water added slowly down the inside of the vial, followed by gentle swirling and refrigeration. Some of that rests on evidence, and some is habit.

Bacteriostatic water. The US label for one widely sold product describes sterile water with 0.9% or 1.1% benzyl alcohol as a preservative, supplied in a multiple-dose container for repeated withdrawals. The preservative is why guides prefer it for a vial that gets punctured over days or weeks. The label also notes that some drugs are incompatible with benzyl alcohol, which hasn't been checked for most research peptides.

Shaking. Older guides, including this page, said shaking "shears" the amino acid bonds. It doesn't: ordinary shaking doesn't break peptide bonds. The documented concern comes from protein-drug research, where agitation can cause molecules to clump into aggregates; a 2010 study at Roche showed this with a shaken antibody solution. Antibodies are large proteins, and whether short peptides such as BPC-157 (15 amino acids) aggregate the same way hasn't been tested. Gentle swirling costs nothing, which is why most guides suggest it.

Storage after mixing. Vendor guides commonly give 30-60 days in the refrigerator once a vial is reconstituted, and longer for unmixed powder in the freezer. We found no published stability data behind those figures for most research peptides, so treat them as vendor estimates.

What we still don't know

The biggest gap is the one this page started with. Nobody has mapped the dose-response curve for subcutaneous GHRPs at the fixed doses users take, so the "saturation dose" remains a community rule of thumb built on IV data that kept rising past it. We also don't know whether bedtime timing or split dosing changes any outcome people care about, or whether repeated use dulls the response; that last question is covered in our page on cycling and receptor desensitization.

For what years of use might mean, see our page on long-term effects. As of October 2026, WADA's Prohibited List bans all of the GH secretagogues and GHRH analogs named here at all times (section S2.2.4), and BPC-157 under S0.