Metabolic

Peptides, MK-677 and your blood sugar

Why growth hormone and its secretagogues push fasting glucose and HbA1c up, how the three numbers sit together, and what to raise with your doctor.

Updated 2026-11-08 · Part of the Magno guides

Growth hormone raises blood sugar. That is not a side effect, it is part of what the hormone does. Anything that raises growth hormone, whether it is GH itself, MK-677, ipamorelin or CJC-1295, can raise fasting glucose and blunt insulin. Plenty of people find this out on their first panel after starting.

The three numbers to read together

• Fasting glucose often moves first. Under 100 mg/dL (5.6 mmol/L) is normal; 100 to 125 is prediabetes on paper.
• Fasting insulin shows how hard the pancreas is working to keep glucose there. Labs accept up to about 25 µIU/mL; lower figures, under 8 or so, are commonly quoted as better. Normal glucose with high insulin often means early insulin resistance.
• HbA1c averages about three months of blood sugar. Under 5.7 percent is normal. On testosterone it can read a little low, because red cells turn over faster and donations replace old cells with new, so a good HbA1c does not cancel out a high fasting glucose.

Why it happens

Growth hormone tells the liver to release glucose and tells muscle and fat to use less of it. MK-677 does this around the clock, which is why it is a common cause of a surprise prediabetic reading in someone lean and training hard. Body fat, poor sleep and high cortisol add to it.

Things to raise with your doctor

• Every compound you take, including peptides, with the start date and any change. A doctor cannot read your glucose without knowing what is raising growth hormone.
• Fasting glucose, fasting insulin and HbA1c from the same draw, and the change since your last test.
• Whether HbA1c is reliable for you, given testosterone and any blood donations.
• Fasting glucose of 126 mg/dL (7 mmol/L) or more on two tests is the diabetes threshold, whatever caused it. That one belongs with your doctor straight away.

Keep the line

HbA1c takes about three months to reflect a change, so one panel says little. Keeping the three numbers on one line, next to the dates you started or changed a compound, is what makes the pattern visible.