IGF-1 Results After Stopping Tesamorelin

[Zydeceltico]

TLDR: My IGF-1 went up after I quit tesamorelin.

7/16/25: IGF-1 came back at 108

8/6/25: began tesa @ 2mg/day

8/26/25: IGF-1 came back at 188; kept running tesamorelin @ 2mg/day

12/8/25: quit tesamorelin completely because heart surgery was coming up, and never restarted it.

1/16/26: IGF-1 came back at 202 (nothing else besides stacked tirz and survo the whole time).

Every lab was run through Labcorp.

Between Aug and Dec I dropped 38 lbs.

On 1/16/26 this wasn't what I was expecting to see.

Thoughts?

 

[cheaperseeker]

My hunch would be that your IGF-1 actually climbed further between August and December, and simply has not fully come back down yet.

 

[Zydeceltico]

cheaperseeker said:

My hunch would be that your IGF-1 actually climbed further between August and December, and simply has not fully come back down yet.

That would usually make sense to me too, but from what I've gathered, the IGF-1 boost you get from tesamorelin drops away far faster than that — basically right away, somewhere in the range of a few days up to 1 week.

 

[Jfrick11]

Zydeceltico said:

TLDR: My IGF-1 went up after I quit tesamorelin.

7/16/25: IGF-1 came back at 108

8/6/25: began tesa @ 2mg/day

8/26/25: IGF-1 came back at 188; kept running tesamorelin @ 2mg/day

12/8/25: quit tesamorelin completely because heart surgery was coming up, and never restarted it.

1/16/26: IGF-1 came back at 202 (nothing else besides stacked tirz and survo the whole time).

Every lab was run through Labcorp.

Between Aug and Dec I dropped 38 lbs.

On 1/16/26 this wasn't what I was expecting to see.

Thoughts?

There are several possible reasons for this, and it isn’t quite as strange as it first appears:

IGF-1 is not a simple direct reflection of tesamorelin use. Tesamorelin boosts GH pulsatility, but IGF1 is strongly influenced by liver sensitivity, nutrition, insulin status, inflammation, and illness or stress.

Obesity means GH resistance. When you began tesa in Aug, you were still heavier and probably more GH resistant, so IGF1 didn’t increase much (188). After a 38 lb loss, hepatic GH sensitivity may improve, which can allow higher IGF1 even without tesa.

Severe calorie restriction can lower IGF1, but after weight loss stabilizes and insulin sensitivity improves, especially with tirzepatide, IGF1 often rises again.

Surgery and stress timing matter. You stopped tesa before heart surgery. Inflammatory stress and recovery can temporarily reduce IGF1, with a rebound weeks later.

Assay variability is real. Lab IGF-1 can differ by 10–20% between draws depending on fasting status, time of day, recent illness, and binding protein dynamics.

GLP-1/GIP agonists do not directly raise IGF1, but better insulin signaling can indirectly increase hepatic IGF1 production.

For me....

This seems more consistent with improved GH sensitivity after major weight loss, not a paradoxical effect from stopping tesamorelin. If IGF1 continues rising into supraphysiologic range without GH secretagogues, that is when closer monitoring is worthwhile (trend > single value).

If this were me, I’d recheck in ~8–12 weeks under consistent conditions (fasted, morning, stable weight) before drawing conclusions.

 

[Zydeceltico]

Jfrick11 said:

Zydeceltico said:

TLDR: My IGF-1 went up after I quit tesamorelin.

7/16/25: IGF-1 came back at 108

8/6/25: began tesa @ 2mg/day

8/26/25: IGF-1 came back at 188; kept running tesamorelin @ 2mg/day

12/8/25: quit tesamorelin completely because heart surgery was coming up, and never restarted it.

1/16/26: IGF-1 came back at 202 (nothing else besides stacked tirz and survo the whole time).

Every lab was run through Labcorp.

Between Aug and Dec I dropped 38 lbs.

On 1/16/26 this wasn't what I was expecting to see.

Thoughts?

There are several possible reasons for this, and it isn’t quite as strange as it first appears:

IGF-1 is not a simple direct reflection of tesamorelin use. Tesamorelin boosts GH pulsatility, but IGF1 is strongly influenced by liver sensitivity, nutrition, insulin status, inflammation, and illness or stress.

Obesity means GH resistance. When you began tesa in Aug, you were still heavier and probably more GH resistant, so IGF1 didn’t increase much (188). After a 38 lb loss, hepatic GH sensitivity may improve, which can allow higher IGF1 even without tesa.

Severe calorie restriction can lower IGF1, but after weight loss stabilizes and insulin sensitivity improves, especially with tirzepatide, IGF1 often rises again.

Surgery and stress timing matter. You stopped tesa before heart surgery. Inflammatory stress and recovery can temporarily reduce IGF1, with a rebound weeks later.

Assay variability is real. Lab IGF-1 can differ by 10–20% between draws depending on fasting status, time of day, recent illness, and binding protein dynamics.

GLP-1/GIP agonists do not directly raise IGF1, but better insulin signaling can indirectly increase hepatic IGF1 production.

For me....

This seems more consistent with improved GH sensitivity after major weight loss, not a paradoxical effect from stopping tesamorelin. If IGF1 continues rising into supraphysiologic range without GH secretagogues, that is when closer monitoring is worthwhile (trend > single value).

If this were me, I’d recheck in ~8–12 weeks under consistent conditions (fasted, morning, stable weight) before drawing conclusions.

Thanks for laying all of that out—really helpful! I'll follow your suggestion and get it tested again in March.