Do libidos really just 'fluctuate'? What TRT research says

What did @sexwithemily actually say?

Sex educator Emily Morse told her 56K viewers not to panic about low libido because "our sex drive, libido, it fluctuates over time" across decades and even week to week. She pointed to medications like birth control and antidepressants, diet, exercise, blood flow, body confidence, and partner communication as variables worth examining. Her core message: libido is "not lost, it is not dead," it just takes self-awareness and patience to reconnect with.

She also made a softer, arguably more interesting point: that giving yourself permission to not want sex sometimes, and redirecting energy to non-sexual pleasure, can paradoxically restore desire. That framing is closer to acceptance-based sex therapy than pop wellness advice, and it deserves credit.

Does the science back this up?

Mostly, yes. Libido variability is well-documented across the lifespan and shorter time cycles, and the lifestyle factors she named are legitimate. But her framing glosses over cases where low libido is a diagnosable medical condition that does not resolve on its own.

A 2017 review by Clayton and Valladares Juarez in Psychiatric Clinics of North America confirmed that selective serotonin reuptake inhibitors (SSRIs) and hormonal contraceptives are among the most common pharmacological suppressors of libido. On the exercise front, a 2021 study by Stanton et al. in Archives of Sexual Behavior found aerobic exercise increased genital arousal response in women with antidepressant-associated sexual dysfunction. Blood flow as a mechanism for arousal is also well-grounded, with research on nitric oxide pathways in both male and female genital tissue dating back to work by Burnett et al. in the 1990s.

The paradox of desire she describes, that backing off sexual pressure can restore libido, maps onto what sex therapists call "spectatoring reduction" and is consistent with Basson's 2000 model of responsive desire published in Obstetrics and Gynecology.

What did they get wrong (or right)?

She got the lifestyle and medication angle right, and she deserves credit for naming antidepressants and birth control specifically. Many creators in this space avoid anything that sounds like a drug critique.

What she missed is clinically significant. Persistent low libido can signal hypogonadism, thyroid dysfunction, hyperprolactinemia, or other endocrine disorders that "giving yourself grace" will not fix. A 2019 study by Shifren et al. in Menopause found that up to 43% of women with hypoactive sexual desire disorder (HSDD) had identifiable hormonal contributors. Framing libido loss exclusively as a psychological or lifestyle issue, without flagging when to see a doctor, is a meaningful omission in a video watched by people who may already feel dismissed by healthcare providers.

She also said "so much about arousal has to do with blood flow" without distinguishing arousal from desire. These are related but separate processes, a distinction that matters when someone is troubleshooting a real problem. Arousal is vascular and physiological; desire is motivational and neurochemical. Conflating them leads people down the wrong optimization path.

What should you actually know?

Libido variability is normal and real. But "normal fluctuation" and "diagnosable low libido" are not the same category, and knowing which one you are dealing with changes what you should do next.

If low libido has lasted more than three to six months, is causing personal distress, and is not clearly tied to a stressor or new medication, that meets the clinical threshold for HSDD per DSM-5 criteria. That warrants a conversation with a clinician, not a tracking app.

Testosterone plays a role in libido for both men and women. In men, clinically low testosterone, defined as serum levels below 300 ng/dL with symptoms, is a recognized driver of low libido and is treated through TRT under endocrine guidelines. In women, off-label testosterone use for HSDD has accumulating evidence but no FDA-approved formulation, leaving patients in a gap that requires specialist guidance.

• If you are on an SSRI and notice libido changes, ask your prescriber about augmentation strategies or alternatives. Do not stop medication unilaterally.
• If you are on hormonal contraception and suspect it is affecting desire, combined oral contraceptives can lower sex hormone binding globulin, which affects free testosterone levels. A provider can review your specific formulation.
• Persistent fatigue plus low libido is a reason to get thyroid function and hormone panels checked, not just to "track" your mood week to week.

The bottom line

Emily Morse is a credible voice on sexual wellness and this video is mostly responsible. The advice to reduce self-judgment, examine medications, and pay attention to lifestyle factors is sound. What is missing is a clear signal that chronic, distressing low libido is a medical symptom, not a mindset problem. Viewers who needed to hear "see a doctor" did not get that here.