Low libido in women — beyond HSDD and what the workup should include

This is not a relationship problem. It may not be a psychological problem at all. The framing that women's sexual desire is primarily relational and emotional — that if desire is low, the origin must be in how she feels about her partner or herself — has led to an enormous amount of dismissal and misdirection in clinical care. When a man presents with low libido, the workup is physiological: testosterone, thyroid, prolactin, vascular assessment. When a woman presents with the same complaint, she is often referred to couples therapy. Both experiences have physiological and psychological dimensions, but the asymmetry in how they are approached reflects a cultural assumption that women's desire is relational by nature and therefore outside the domain of physiological investigation. That assumption has been wrong for a long time, and it has cost a lot of women years they could have spent with answers.

Here is what a proper physiological workup for low libido in women should include, and why each piece matters.

Thyroid function is the first thing to rule out. Hypothyroidism — underactive thyroid — is one of the most common endocrine conditions in women, affecting roughly 5-10% of adult women, with a significant additional percentage in subclinical hypothyroidism. Low thyroid function suppresses nearly every metabolic and energy-dependent process in the body; libido is among the earliest casualties. Fatigue, cold sensitivity, cognitive dulling, dry skin, cycle irregularities — these often accompany hypothyroid-related low libido but aren't always present or aren't attributed to the thyroid without testing. TSH alone misses a meaningful portion of thyroid dysfunction; a complete thyroid panel including free T3, free T4, and thyroid antibodies gives a more complete picture. If your thyroid has never been adequately evaluated in the context of low libido, it should be.

Iron status — specifically ferritin, the storage form of iron — is underappreciated in the context of desire and energy. Low ferritin, even at levels that don't meet the clinical threshold for anemia, is associated with fatigue, cognitive fog, and reduced motivation. The brain needs iron for dopamine synthesis; dopamine is the neurotransmitter most central to motivation, reward, and the wanting component of desire. Women who menstruate are losing iron monthly and are at baseline higher risk for ferritin depletion than men; women with heavy periods or recent pregnancies are at significantly higher risk. A ferritin level under 30-40 ng/mL, even with a normal hemoglobin, can contribute meaningfully to a low-libido picture and is worth addressing on its own terms.

Testosterone in women is the most systematically understated part of this conversation in mainstream medicine. The narrative that testosterone is a male hormone has left its role in female physiology poorly understood and consistently undertested. Women produce testosterone — in the ovaries and the adrenal glands — and it has direct roles in libido, arousal, energy, mood, and muscle maintenance. Free testosterone — the bioavailable fraction that isn't bound to sex hormone-binding globulin — is the clinically relevant number. Low free testosterone in women is a real entity with real consequences, and it is common, particularly in the years of perimenopause and menopause, after oophorectomy, and in women who have been on combined oral contraceptives.

SHBG — sex hormone-binding globulin — is the binding protein that determines how much testosterone is free and biologically active. SHBG is elevated by oral estrogen, including the estrogen in combined oral contraceptives. This means that women on the pill often have substantially elevated SHBG — sometimes two to four times the baseline — which binds to free testosterone and reduces its bioavailability significantly. This is a direct, physiological mechanism by which oral contraceptives can suppress libido; it is not a psychological adaptation or an emotional side effect. It is a biochemical consequence of the route of administration, and it can persist for months to a year or more after the pill is stopped because SHBG elevation can outlast the pill itself. Testing free testosterone and SHBG together — not just total testosterone — gives a meaningful picture of the androgenic milieu. Transdermal estrogen, by contrast, does not drive SHBG elevation in the same way, which is one reason route of administration matters in hormonal contraception and in menopausal hormone therapy.

Prolactin belongs in the workup. Elevated prolactin — hyperprolactinemia — can occur from a prolactin-secreting pituitary adenoma (prolactinoma), from certain medications including antipsychotics and some antiemetics, or from hypothyroidism, which elevates TRH and secondarily drives prolactin production. Hyperprolactinemia suppresses GnRH pulsatility, which reduces LH and FSH, which reduces estrogen and testosterone. The libido consequence is direct and significant. A prolactin level is a simple blood test and it is worth checking.

Depression screening matters here, both because depression independently reduces desire and because antidepressant medications — particularly SSRIs and SNRIs — are among the most significant pharmaceutical drivers of reduced libido in women. SSRIs raise synaptic serotonin, which has inhibitory downstream effects on dopamine and on the central sexual arousal circuits. The sexual side effects of SSRIs are documented and common — affecting an estimated 30-60% of users — and they are frequently attributed to the depression itself rather than the medication. If you started an SSRI and libido declined afterward, the medication is the more probable cause. This is worth an explicit conversation with your prescribing provider about timing, dose, formulation, and alternatives.

The diagnostic categories for female sexual dysfunction are worth understanding. Hypoactive sexual desire disorder (HSDD) refers specifically to absent or reduced sexual desire that causes personal distress — the distress criterion distinguishes it from simply low-but-acceptable desire. Flibanserin (Addyi) and bremelanotide (Vyleesi) are both FDA-approved for HSDD in premenopausal women. They operate through different mechanisms: flibanserin is a 5-HT1A agonist and 5-HT2A antagonist that is taken daily and modulates the serotonin-dopamine balance centrally; bremelanotide is an on-demand injection that activates melanocortin receptors and has central effects on sexual arousal. Female sexual interest/arousal disorder (FSIAD) captures the broader combined picture of both desire and arousal impairment. Secondary low libido — loss of previously present desire attributable to a specific cause — covers the thyroid, iron, testosterone, SHBG, prolactin, and medication causes outlined above, and is arguably the most important category to work through first because its causes are often addressable.

PT-141 — bremelanotide, brand name Vyleesi — deserves specific clinical framing. It is FDA-approved for premenopausal women with HSDD; use in postmenopausal women is off-label, meaning it hasn't undergone the formal regulatory review process for that indication, though it is used in clinical practice. Its mechanism is distinct from hormonal interventions: it is a melanocortin receptor 4 agonist that activates central neural circuits involved in sexual arousal and desire, working upstream of the hormonal system. It has meaningful evidence for increasing desire and reducing distress related to HSDD in the populations studied. It is a conversation-starter with a sexual health specialist or gynecologist, not a self-directed intervention, and it belongs within a comprehensive evaluation rather than as a standalone first step.

Kisspeptin-10 occupies an upstream position in the neuroendocrine architecture of desire. Kisspeptin is the critical activator of GnRH neurons in the hypothalamus — it is essential for the pulsatile GnRH release that drives LH, FSH, and ultimately sex hormone production. Kisspeptin-10 has been studied in clinical research for its capacity to modulate LH pulsatility and steroid hormone production, and there is research interest in its role in sexual motivation given kisspeptin's demonstrated effects on sexual arousal in animal models and emerging human data. This is active research rather than established clinical practice; it does not constitute an approved treatment, but it is a mechanistically interesting area of investigation for the upstream hormonal architecture of desire.

The testosterone optimization conversation in women deserves emphasis because it remains poorly integrated into standard care despite a substantial evidence base. The British Menopause Society and the International Society for the Study of Women's Sexual Health both have position statements supporting testosterone therapy for women with low libido where other causes have been addressed. Formulations in the available approved pharmacopeia are not optimally designed for women's doses; this leads to the use of compounded testosterone preparations or off-label use of male-formulated products at a fraction of the male dose. A prescribing provider who is fluent in female testosterone therapy — including how to dose it, how to monitor it, and what symptoms and lab values indicate adequate versus excessive dosing — is a meaningful specialist to seek out.

The workup for low libido in women is not optional. It is not automatically a psychological matter. It may be — or there may be a psychological component alongside a physiological one — but that determination requires first ruling out the thyroid, iron, testosterone, SHBG, prolactin, and medication contributors that are directly addressable. Finding a gynecologist or sexual health specialist who approaches this evaluation with the same rigor applied to other endocrine investigations is the most important first step, and that provider exists. The question of why desire has gone quiet is a physiological question that deserves a physiological investigation.