More Than GLP-1s: How Hormones Like Cortisol, Thyroid, and Estrogen Affect Weight Loss

Most people think of weight loss as a simple equation: eat less, move more. And with medications like Semaglutide or Tirzepatide, it’s easy to assume the medication will do most of the heavy lifting.

But our bodies don’t run on simple math. They run on hormones -- a whole network of chemical messengers that regulate appetite, metabolism, mood, energy, sleep, and more. And when even one of them is off, it can impact your progress.

Here’s a breakdown of some of the most common hormone imbalances I see in my clinic, especially in women -- and how they can shape your weight loss journey.

Cortisol: The Stress Hormone That Won’t Let Go

Cortisol is released in response to stress. In small bursts, it’s helpful. But when stress is constant, or sleep is poor, cortisol can stay elevated for too long. That can lead to:

-- Increased belly fat -- Insulin resistance -- Cravings for sugar or carbs -- Slower metabolism

Even when you’re on a GLP-1, high cortisol can block your body’s ability to release weight.

What helps: consistent sleep, less screen time before bed, walks or stretching, deep breathing or journaling, and boundaries around your time and energy. Sometimes, you don’t need to push harder -- you need to help your system calm down.

Thyroid: The Metabolism Regulator

Your thyroid helps regulate your energy, mood, and how efficiently you burn calories. Even a slightly underactive thyroid -- what we call subclinical hypothyroidism -- can make it harder to lose weight. Symptoms can include:

-- Fatigue -- Feeling cold -- Slowed digestion -- Mood dips -- Weight gain or plateau despite effort

If you suspect thyroid issues, don’t stop at TSH alone. Ask about Free T3, Free T4, and thyroid antibodies to get the full picture.

Estrogen and Progesterone: The Midlife Shift

During perimenopause and menopause, estrogen and progesterone start to fluctuate and eventually decline. That transition can bring new challenges -- and it often hits right when you feel like you’re finally ready to take care of yourself again. Common effects include:

-- Increased belly fat -- Sleep disruption (especially from low progesterone) -- Insulin resistance -- Slower or less consistent results from GLP-1s -- Anxiety, irritability, or brain fog

What helps: strength training, consistent protein intake, blood sugar balance, and possibly hormone replacement therapy if it’s appropriate for your body and stage of life.

What To Do If You Suspect a Hormone Imbalance

If you’re following your plan, taking your medication, eating well, and moving your body -- and the results just aren’t coming -- it’s time to look under the hood. Here’s where to start:

-- Ask your provider about comprehensive labs -- Track symptoms like fatigue, mood, hair changes, sleep, or cycle shifts -- Take your stress and sleep seriously -- Work with someone who sees the full picture -- not just your weight, but your hormones, nervous system, and capacity

Final Thoughts

GLP-1s are powerful tools. But they’re not the whole story.

If your progress has slowed or stalled, it may not be about willpower -- it may be your hormones. And if that’s the case, you don’t need to do more. You need a provider who can listen, dig deeper, and help you understand what’s really going on.

If this resonates with you, reach out. I’m here to help.

Katharine, NP

New Day Weight Loss