Cortisol and GLP-1 — HPA axis during caloric deficit

Posting this for discussion as it's directly relevant to our lab results & biomarkers community. I'll summarize the key findings and then share my interpretation.

Background: Cortisol and GLP-1 HPA axis during has been a topic of significant interest. The latest data adds substantially to our understanding of the efficacy and safety profile in this area.

Key findings:

• Primary endpoint met with statistical significance (p<0.001)
• Effect size consistent with or exceeding Phase 2 projections
• Adverse event profile in line with the known GLP-1 receptor agonist class effects — primarily GI (nausea 20-25%, diarrhea 12-17%)
• Subgroup analyses showed benefit across BMI categories, age groups, and baseline metabolic status

My interpretation:

This is meaningful for several reasons. First, it confirms that the results from earlier-phase trials are reproducible at scale. Second, the safety data with longer follow-up is reassuring. Third, the subgroup consistency suggests this isn't driven by a specific patient phenotype.

I'd love to hear from others — especially those with clinical or research backgrounds. What are the limitations you see? What questions remain unanswered?

Clinical perspective on Cortisol and GLP-1 HPA axis during:

I have managed roughly 300 patients on GLP-1 therapy and this topic comes up frequently. What the data shows — and what I see in practice — is that the medication works best as part of a comprehensive approach.

For this specific question, I would recommend: getting comprehensive baseline labs first.

Dr.EM_Chicago said:

What the data shows — and what I see in practice — is that the medication works best as part of a co

This is exactly right. Dr.EM_Chicago articulated what I have been trying to explain to my doctor for months. The Cortisol and GLP-1 HPA aspect is the most important factor.

Relevant to Cortisol and GLP-1 HPA axis — here is my latest bloodwork comparison:

Key improvements: A1C 7.6% → 5.5%, triglycerides 221 → 91 mg/dL, hsCRP 8.0 → 0.9 mg/L. All on tirzepatide for 13 months.

The inflammatory marker drop is what impresses me most. Consistent with the SELECT trial's cardiovascular findings.

Dr.EM_Chicago said:

What the data shows — and what I see in practice — is that the medication works best as part of a co

I respect Dr.EM_Chicago perspective but I think this oversimplifies things a bit. Re: Cortisol and GLP-1 HPA axis — the effect size varies considerably by population.

I am not saying Dr.EM_Chicago wrong entirely — just that the picture is more nuanced than a blanket statement. The SUSTAIN data specifically shows different outcomes in different metabolic phenotypes.