A patient came to see me in her mid-40s. In six months, she'd gained 50 pounds. Not gradually. Rapidly. Like her metabolism had just stopped.

We checked thyroid. Lowered inflammation. Optimized diet and exercise. Even added a low-dose GLP-1. 

Nothing moved.

What finally worked was HRT and semaglutide — together. Within months, she was losing weight for the first time in over a year.

I thought about her when I saw new data on the combination of GLP-1s and HRT published in February 2026. What happened in her case is not coincidence. It's biology.

This week, I'm digging into why — and what it means for any woman in midlife who isn't getting the metabolic results she expected.

If you're a woman in mid-life on a GLP-1 — or considering one — here's where to start:

👉 These aren't separate decisions. For many women, optimizing hormone levels is what makes the metabolic treatment work.

❌ The old assumption: GLP-1s work the same in everyone.

The pivotal GLP-1 trials — the ones generating the headline weight loss numbers — were run mostly in younger, premenopausal participants. Postmenopausal women weren't well represented. So when a postmenopausal woman takes tirzepatide and loses less weight than expected, it's often chalked up to age. Turns out, it may be her hormones.

✅ The new reality: without HRT, postmenopausal women lose significantly less weight on GLP-1s. With HRT, they match what younger women achieve in trials.

A Mayo Clinic study in The Lancet (2025) followed 400 postmenopausal women on tirzepatide for 12+ months:

The same pattern appeared with semaglutide in Menopause (2024) — greater weight loss at every checkpoint over 12 months.

💥 Two different GLP-1s. Same result.

🔬 Why: estrogen and GLP-1 share the same brain circuits.

Estrogen upregulates GLP-1 receptors in the gut and brain. More receptors = stronger signal = more appetite suppression from the same dose.

Estrogen also stimulates your intestinal cells to produce more of your own GLP-1 — so you're starting from a higher baseline.

And they activate the same downstream pathways in the liver, fat tissue, and pancreas. 

One plus one doesn't equal two. It equals more.

When estrogen drops in menopause, the efficiency of that entire system drops with it.

Two things I want to be clear about before the protocol.

GLP-1s are not for everyone. They're most appropriate for women dealing with metabolic syndrome, insulin resistance, or weight gain that hasn't responded to every other tool. Functional medicine means using the best tool for the job — sometimes that's food and lifestyle, sometimes it's a drug, sometimes it's both.

MHT (menopausal hormone therapy), on the other hand, I think of as one of the most powerful longevity tools we have for women — full stop. The data on cardiovascular protection, bone density, and cognitive health is beyond compelling, especially when started in perimenopause or close to menopause. We've moved well past the fear era of the early 2000s.

Don't guess. Get a full panel — estrogen, progesterone, testosterone, FSH — plus a metabolic workup. At Parsley, this is the foundation before we make any metabolic recommendations.

Research supports initiating MHT in perimenopause, or within 10 years of menopause onset, for the greatest protective effects on heart and brain. If you're already postmenopausal and symptomatic, it's still worth the conversation.

Women without HRT on tirzepatide lost below what clinical trials predict. If that sounds like your experience, your hormones may be the missing piece — not your effort, not your diet, not your willpower.

On a GLP-1, up to 40% of weight lost can be lean mass if you're not actively protecting it. Strength training 2–3x/week and 80–100g+ protein daily are non-negotiable.

👉 The goal: hormonal health and metabolic health aren't separate lanes. For many women, fixing one is what unlocks the other.

Big birthdays and sculptural facials. 

February is always a big month for me. Two of my three kids have birthdays this month — and so does Parsley, which was in some ways my first baby. So if you count it, that's 3 of my 4 kids' birthdays. 🙂

This month, Parsley turned 10. My oldest turned 9. I honestly don't feel old enough to have a 10-year-old company or a 9-year-old human child. But here we are.

Maybe we all feel younger than we are. I feel about 39 — not almost 45. Physically, I'd say closer to 30 (that's what my Parsley longevity labs tell me). Emotionally, I'll take the extra decade. The wisdom I've gained over these 10 years — as a mother, as someone running a company, as a wife learning how to be a better wife, and through real spiritual growth — I wouldn't give that up for anything.

This week we're on spring break in Costa Rica, where I had something called a "sculptural facial" — which is less a facial and more a deep face, neck, and shoulder massage with lymphatic drainage. The practitioner put on gloves and worked inside my mouth to release tension from my jaw and face from the inside out. When she was done, I looked in the mirror and genuinely couldn't believe it. More awake. Eyes more open. Cheekbones higher. The lines in my forehead — gone. More than after any facial, Botox, or yoga class I've ever done.

It was a reminder: how we look, feel, and experience aging is plastic. Progress isn't linear. You can turn back the clock in surprising ways.

Longevity isn’t about fighting aging. It’s about flowing with it — which means being grateful for the birthdays marking time, for the wisdom that comes with them, and for the tools keeping my cells, sinews, and collagen tracking about 10 years behind. I’ll take it all. 

Stay strong, stay curious and breathe, 

Robin

Wondering if your hormone levels are affecting your metabolism — or whether you're a candidate for HRT, a GLP-1, or both? That's exactly what we dig into at Parsley.

Book your longevity labs here, or bring your own and book a consult with a Parsley clinician for a personalized treatment plan.

As always, this newsletter is for informational and educational purposes only and is not intended as medical advice. Always consult your healthcare provider before making any health decisions or changes to your treatment plan.