May 8, 2026
By:
Dr. Brittany Busse
Director of Velocity Women’s Care
For decades, women have been taught that they need to make themselves as tiny as possible to fit societal beauty standards. In the 90s, we called this tiny look “heroin chic.” In the early 2000s, we idolized anyone whose hip bones cut through their low-rise jeans. The message was always the same: thinner is better, and if you’re anything but thin, you’re undisciplined. Women watched celebrities get publicly criticized for gaining weight and praised for shrinking themselves, internalizing a standard that wasn’t designed to promote health, but to promote an arbitrary physical appearance.
That pressure to be tiny hasn’t gone away. Today, with the rise of GLP-1 peptides, we’re seeing a powerful medical tool—one that has been genuinely life-changing for women with obesity—repurposed to chase the same outdated ideal as before. And when medications meant to treat disease are used to push already healthy or even underweight women further toward thinness, the consequences are often terrible. GLP-1 peptides can have catastrophic effects on thyroid function, fertility, and overall hormonal health. And we at Velocity Health believe this information isn’t getting nearly the amount of attention it should.
Let’s be clear: we at Velocity believe that GLP-1 and multi-receptor agonists (including semaglutide, tirzepatide, and newer peptide agents like retatrutide) are a remarkable development in medicine. For women whose weight has been the barrier between them and the life they want, these therapies can be transformative in ways that go far beyond aesthetics. The downstream consequences of obesity-related metabolic dysfunction (including chronic inflammation, insulin resistance, cardiovascular strain, sleep apnea, joint degradation) can be very serious. And when peptide therapy helps reverse that trajectory, it is doing exactly what medicine should do.
The Aesthetic Agenda Latches Onto a Medical Tool
Unfortunately, within a few years of GLP-1 medications becoming widely available (or at least, the GLP-1 agonists associated with weight loss exceeding 10% of body weight), the cultural conversation had moved far beyond the clinical populations for whom the peptides were originally developed. Celebrities began to openly discuss using them. People with “ozempic face”—the gaunt, hollowed-out appearance that can result from rapid significant weight loss—became a topic of mainstream commentary, and this appearance was often framed not as a negative side effect but as a chic new “look.” And before we knew it, a generation of women who were never metabolically ill began seeking access to medications that were never designed for them.
This article is not meant to be a condemnation of those women. The cultural pressure they are responding to has been building for decades, is genuinely relentless, and now operates at an unprecedented scale and intimacy (through phones and social media influencer culture). When the entire information environment a woman inhabits tells her, every day, that a certain body is the goal, and when a medication now exists that makes achieving that body easier than it has ever been, the woman’s resulting behavior is understandable.
The thyroid gland is among the most sensitive indicators of energy availability in the female body, and it is the first part of the body that signals when something is going wrong in that department.
The thyroid produces T4, a relatively inactive precursor hormone. In order for a woman’s body to use thyroid hormone—which regulates metabolism, body temperature, mood, cognitive function, menstrual cycle, and reproductive health—T4 must be converted to its active form, T3. That conversion is carried out by an enzyme called deiodinase. And deiodinase activity is very sensitive to the amount of calories and carbohydrates she’s taking in to fuel herself.
When her energy intake falls too low, whether from deliberate caloric restriction, peptide-facilitated appetite suppression, or both together, her body goes into food scarcity mode. Her deiodinase activity drops. Her T4 accumulates, unactivated, in her bloodstream, and her T3-count stays low. The result of all of this is a symptom picture indistinguishable from hypothyroidism: fatigue, cold intolerance, declining mental sharpness, weight plateau despite calorie restriction, poor sleep, mood changes, and menstrual irregularities.
And here’s what makes this whole situation even worse: many women who experience these symptoms have no autoimmune markers. They don’t have Hashimoto’s thyroiditis. Or Graves’ disease. Or structural thyroid pathology. The thyroid gland itself is technically functioning. T4 production is intact. As far as most doctors can tell, nothing is actually wrong with these women. The problem is purely one of conversion failure, and conversion is failing because the women’s bodies are not receiving enough energy to run the process.
Here’s a succinct overview of this dangerous clinical sequence, which is becoming more and more common:
At Velocity, we believe that, instead of being prescribed levothyroxine (T4) right away, these women need to be asked how much they’re eating (specifically, how many carbohydrates they’re eating) before a diagnosis and treatment is decided on.
The thyroid and the female reproductive hormonal axis are functionally coupled. The same energy deficit that breaks down thyroid conversion also disrupts the hormonal cascade that governs ovulation, cycle regularity, and fertility.
The hypothalamic-pituitary-ovarian (HPO) axis—the hormonal loop coordinating female reproductive function—is also acutely sensitive to energy availability. The body is not going to commit resources to reproduction when it perceives that it does not have enough fuel to sustain a pregnancy. So, when caloric intake falls below what is needed to support both baseline metabolic function and reproductive function, the HPO axis downregulates. Estrogen production decreases, and ovulation becomes irregular or ceases. This results in difficulty conceiving, which could cause a woman to pursue expensive fertility treatments like IVF, all for a condition that was caused by under-nourishment and might have been reversed if she just ate more.
Thyroid and reproductive hormones do not fail in isolation. The downstream effects of chronic under-nourishment in women affect multiple other bodily systems:
This is the body’s sustained stress response to perceived energy scarcity, which further suppresses both thyroid conversion and reproductive hormonal signaling
Relevant to cycle regularity and, in postpartum women, lactation
This negatively impacts lean muscle mass preservation, bone density, and recovery from exercise.
Estrogen is critically protective of women’s bones. Hypoestrogenic states from under-nourishment accelerate bone loss in ways that may not manifest clinically until decades later.
Emerging evidence links energy restriction to dysbiosis affecting the estrobolome, the subset of gut bacteria responsible for estrogen metabolism and reactivation.
Individually, each of these effects is significant. Together, in a woman who has lost weight well below her functional optimum while pursuing an aesthetic ideal, they represent a pattern of global functional decline. And unfortunately, this global decline is frequently misread as multiple separate conditions rather than attributed to a single root cause.
Just to reiterate: none of this is meant to be an argument against peptide therapy. It is an argument for reclaiming its intended use, and for insisting that these tools be used with a clinical framework that defines success by function, not by appearance.
For women who are carrying weight that is limiting their cardiovascular health, mobility, metabolic function, or quality of life, peptide-facilitated weight loss should be tracked against markers that actually reflect health:
A woman who is losing weight on a peptide protocol while simultaneously experiencing worsening fatigue, disrupted cycles, declining athletic performance, and decreasing cognitive function is not getting healthier. She is trading one set of metabolic problems for another, and the new set may take longer to identify and longer to reverse.
The women who are most likely to read content like this are usually not the patients for whom GLP-1 medications were designed. They are lean, active, health-conscious, and regular consumers of health and wellness content. Research on thyroid function and weight status consistently shows that women in the normal weight range tend to have relatively stable thyroid function under most conditions.
But this type of woman also makes up the subset of the population that has been most shaped by decades of cultural messaging about body weight. She has internalized the ideals of restricting oneself to look as tiny as possible. And she is now living in a moment when a medication exists that makes significant weight loss more accessible than ever, at exactly the same time that social media is delivering a newly intensified version of the thin ideal directly to her phone.
To this woman, we at Velocity want to say: the skinny ideal did not emerge from medical evidence. It emerged from advertising, fashion, and a culture that has historically profited from women’s dissatisfaction with their bodies. It has been repackaged for every generation, and it is being repackaged again now, this time with a prescription attached. The functional consequences are the same as they always have been.
Your thyroid, hormones, and fertility are functional systems, not cosmetic ones. And they will let you know whether you are actually taking care of yourself or just performing the appearance of it. The true measure of success for weight loss treatment is whether a woman feels better and can function at a higher level than she could before.
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