Educational information only. Not medical advice. Talk to a qualified healthcare professional before using any compound. Disclaimer

LimitlessLab
Search the library Wishlist Cart, items: 0
MK-677

Growth Hormone & Muscle

MK-677

Also known as Ibutamoren, Ibutamoren mesylate, L-163,191, Nutrobal

Moderate human evidenceNot approvedWADA prohibitedNot a peptide

Price range: €34 through €67

Discussed for: Oral GH and IGF-1 boost.

Sequence: not listed. Modified or non-standard residues are left out on purpose.

Effect strengthHow hard it acts on the body6/10
Proof levelHow well that is shown in humans6/10
Risk levelHow much can go wrong6/10

Editorial 1 to 10 estimates from published research, not measured values. How to read these

Save to wishlist
Save to wishlist

01 / Identity

What it is

MK-677 is a small molecule, not a peptide. Main reported uses: oral GH and IGF-1 boost. Current status: not approved.

Molecule type
Small molecule, not a peptide
How it is taken
Oral
Other names
Ibutamoren, Ibutamoren mesylate, L-163,191, Nutrobal

Route only. This library does not publish doses or protocols.

02 / Mechanism

How it is thought to work

Oral ghrelin mimic that raises GH and IGF-1, increases appetite

03 / Potential benefits

What people use it for

Oral GH and IGF-1 boost

Moderate human evidence

Some human trials exist, but they are smaller, shorter or mixed.

Listed uses are what people use it for, not proven outcomes.

04 / Known risks

Side effects and risks

Hunger, water retention, raised blood sugar / insulin resistance, numb hands; heart-failure concern in elderly trial

Risk level 6 of 10

Moderate risk score: real side effects are known, and long-term safety is not settled.

Unknown long-term effects count as a risk, not as a clean record.

05 / Regulatory

Regulatory status

Status
Not approved
Details
Not approved
Sport (WADA)
Yes: S2 (peptide hormones / GH factors)

Status reflects information up to mid-2026 and changes over time. Check current sources.

06 / Evidence quality

How good is the evidence?

Moderate: human trials

How we grade evidence

07 / Notes and sources

Notes and sources

  • Not technically a peptide. It is listed because it is often sold or discussed alongside peptides.
  • Growth-factor peptides carry a theoretical risk of feeding existing cancers.
  • Products sold online as research peptides are unregulated. Tests of such products often find wrong amounts, impurities or a different compound.
  • Anyone using compounds like this regularly should have medical supervision and bloodwork (for example IGF-1, glucose and HbA1c, hormones, lipids).
  • Source: Peptide Reference Table, an editorial review of published research up to mid-2026. Scores are 1 to 10 editorial estimates, not measured values. Regulatory and WADA status change over time.

Educational information only. Not medical advice. Talk to a qualified healthcare professional before using any compound.

Related compounds