These 3 work in 3 different ways, so they are not straight substitutes for each other.
| Comparison | Bimagrumab BYM338 | Ipamorelin NNC 26-0161 | Ipamorelin + CJC-1295 blend CJC/Ipa · CJC-1295 and Ipamorelin |
|---|---|---|---|
| How it works | How it works Bimagrumab is not a weight-loss drug in the usual sense. It changes what you lose rather than how much. | How it works Ipamorelin does not contain growth hormone. It signals your pituitary to release your own, by copying ghrelin, the hormone that makes you feel hungry. | How it works The blend pairs two different signals that reach growth hormone release by separate routes, which is why they are combined rather than doubled up. |
| What it is | An experimental shot that strips fat while adding muscle. | A gentle shot that nudges your body to release its own growth hormone. | The popular growth-hormone combo in one shot, for muscle, recovery, and sleep. |
| Status | In trialsInvestigational | Research only | Research only |
| Typical dose | 10–30 mg/kg per dose | 0.2–0.3 mg per dose | — |
| How often | Monthly | Daily, often at night | Daily, often at night |
| Stays active | Not established | ~2 hours | Not established |
| Dose comes from | Clinical trial protocol | Community practice | No established range |
| Cycled? | Not cycled. Infused every 12 weeks in the trials Clinical trial protocol | Commonly cycled, often quoted as 5 days on and 2 days off, or 8 to 12 weeks on and 4 off Community practice | Each half is cycled on its own schedule, usually 8 to 12 weeks on and 4 off Community practice |
| What it does | |||
| Drug class | Activin receptor antibody | GH secretagogue (GHRP) | GHRH + GHRP combo |
| Used for | An unusual experimental shot that strips fat while adding muscle, by blocking a signal that limits muscle. It is being studied alongside GLP-1 drugs. | A gentle nudge for your body to release more of its own growth hormone. People use it to recover faster from workouts, sleep deeper, build lean muscle, and lose a little fat. | The most popular growth-hormone combo in one shot: one part sets a steady base and the other adds a clean pulse, for muscle, fat loss, recovery, and sleep. |
| Receptors hit | — | — | — |
| Numbers | |||
| Full dose line | 10 up to 30 mg/kg per month (trial doses) | 0.2 up to 0.3 mg per dose (start low, increase slowly) | ~100 mcg CJC + 200-300 mcg ipa |
| Why that cycle | The dosing interval is long because the antibody lasts a long time, not because anyone is cycling it. The phase 2b trial ran 48 weeks blinded with a further 24 weeks open label. | The reason for cycling is real; the schedule is not. Sustained exposure to a ghrelin-receptor peptide blunts the growth hormone response to a later dose, which has been shown in people. But no published study has tested any on/off pattern for ipamorelin, and ipamorelin's own desensitisation has never been measured in humans. Every specific number you see traces back to vendor and clinic pages, including one widely repeated citation to a 2019 study that does not exist. | The pairing exists because the two halves do not blunt each other. Losing response to a ghrelin-receptor peptide does not reduce the pituitary's response to a GHRH peptide, and the reverse is also true. No study has tested this blend on any schedule. |
| Weight / effect | Not measured in a trial | Not measured in a trial | Not measured in a trial |
| Chain length | Not disclosed | 5 residues | Not disclosed |
| Common vial | 10 mg | 5 mg | 10 mg |
| Before you start | |||
| Route | Into a vein or under the skin | Under the skin (subcutaneous) | Under the skin (subcutaneous) |
| Do not use if | No formal contraindications established Pregnancy | Active cancer, as a precaution with anything raising growth hormone Pregnancy Banned in drug-tested sport | Active cancer, as a precaution with anything raising growth hormone Pregnancy Banned in drug-tested sport |
What separates them
Proof behind the dose. Bimagrumab has a dose from a clinical trial protocol. Ipamorelin has a range that comes from community practice, with no published human study behind it. Ipamorelin + CJC-1295 blend has no established dose range at all.
Staying on it. Bimagrumab is taken continuously. Ipamorelin and Ipamorelin + CJC-1295 blend are normally run in blocks with breaks, though for most of these the block length is convention rather than a tested schedule.
What doesn't differ: None of them has a measured effect size from a published trial, so there is no number to rank them on.
What people actually report
Bimagrumab
- It is an antibody rather than a classic peptide, and it is trial-only.
- Severe upper stomach pain, which can signal pancreas inflammation
- Signs of an allergic reaction such as face or throat swelling, hives, or trouble breathing
Ipamorelin
- Generally mild, but it is not approved for this use and is banned in drug-tested sport.
- Signs of an allergic reaction
- New lumps or masses
Ipamorelin + CJC-1295 blend
- It is off-label and banned in drug-tested sport.
- Signs of an allergic reaction
- New lumps or masses
Side effects are what users and trials report most often, not a complete list. Anything sudden, spreading, or breathing-related is an emergency regardless of which compound caused it.
People also compare
This comparison does not cover cost, long-term safety, or how you personally will respond. Effect figures come from separate trials in different populations and are not always directly comparable to each other. Nothing here is medical advice or a recommendation to use any of these. Talk to a clinician about your own situation.