Elevated cystatin c on mild cycle

[riggspersonal]

Got my cystatin c back today and it came back relatively elevated at 1.15mg/L. This was very surprising to me for a few different reasons. Here's some more context:

- 35/Male/215lbs/14% BF. Healthy, very little pharmaceutical or otherwise drug use throughout life. Very little alcohol consumption. No chronic illness.
- Running first real cycle, if you even want to call it that. Started TRT at 125mg/week back in September 2025. Increased to 240mg pharma test cypionate since about 12/17/2025, so just over a month. Also started 2iu HGH and 2mg retatrutide around that time. Have since titrated these up, HGH to 3iu as of two weeks ago and retatrutide to 4mg/week about 3 weeks ago.
- Drink 1 gallon of water per day and have at least two scoops of electrolyte powder


Unfortunately I didn't get my cystatin c tested during my December 17 panel so I am not sure what baseline was, but all other kidney markers were in check. I have some other results pending but in the meantime trying to figure out why this is so elevated.

Any ideas? Could it be due to HGH?

 

[BabaJagga]

good question and i suspect gh could be culprint.

i have been on gh (2-3-4iu max) since last summer and my cystatinin c has risen from 0,8 (first measured around the time ive started gh) and when i tested maybe 2 months later it was 1.02.

mid december, mid blast (750 test, second week of anadrol 50mg daily) it was 1.27.

ive dropped all anabolics, even test for 2 weeks to let my level come down faster and resumed with 200mg weekly. well, gh is still there at 4iu daily...

ive asked chat gpt about that (i know i know) and its said that it could elevate it with some pathway but its (almost?) without kidney stress. there is some mechanism that honestly i dont understand...

but you are not alone.

 

[riggspersonal]

good question and i suspect gh could be culprint.

i have been on gh (2-3-4iu max) since last summer and my cystatinin c has risen from 0,8 (first measured around the time ive started gh) and when i tested maybe 2 months later it was 1.02.

mid december, mid blast (750 test, second week of anadrol 50mg daily) it was 1.27.

ive dropped all anabolics, even test for 2 weeks to let my level come down faster and resumed with 200mg weekly. well, gh is still there at 4iu daily...

ive asked chat gpt about that (i know i know) and its said that it could elevate it with some pathway but its (almost?) without kidney stress. there is some mechanism that honestly i dont understand...

but you are not alone.

Thanks for the reply. I think I ran across a post of yours on this topic while I was searching. I just can't imagine such a mild cycle ran for such a short period of time causing such disruption to kidneys. That certainly didn't come up in my research when I was planning out my next 6-9 months back in November.

 

[BabaJagga]

i will copy answer from chatgpt about its relationship (or part of it).

maybe others with more knowleage will chime in with some other info.

Let me be very clear and precise, because this is an important mental shift:

You can have a chronically “high” cystatin C while using GH, even with healthy kidneys and no ongoing renal damage.

This is not speculation. This is established physiology.

⸻

Why cystatin C can stay high on GH (without kidney damage)

GH increases cystatin C production, not kidney stress
• GH → ↑ cellular activity in all nucleated cells
• More cystatin C is produced before the kidneys even see it
• Kidneys filter it normally, but the incoming load is higher

So blood levels rise even if filtration is normal
This is independent of renal injury

In true kidney damage you’d expect:
• rising creatinine
• worsening urine markers (protein/albumin)
• worsening BP control
• progressive decline over time

You do not have that pattern.

What you have is:
• isolated cystatin C rise
• stable creatinine
• no uremic symptoms
• normal BP
• no edema beyond GH-related water

That pattern is not renal pathology.

⸻

This happens in medical GH patients

Even in:
• children with short stature
• adults with GH deficiency
• long-term endocrine patients

Doctors have published warnings that:

“Cystatin C overestimates renal impairment during GH therapy.”

Some patients never return to baseline cystatin C until GH is stopped — yet their kidneys remain normal.

⸻

What “always high” actually means in practice

Let’s define numbers, since you prefer precision.

For GH users:
• Baseline cystatin C: ~0.7–0.9 mg/L
• On GH: ~1.0–1.3 mg/L is common
• This can remain stable long-term

The key is stability, not the absolute number.

A stable cystatin C of 1.1–1.2 for years on GH
far safer than a rising cystatin C from 0.9 → 1.4 in 3 months without GH