Low libido is rarely just stress or aging. It is a real signal from your hormones, your metabolism, and your nervous system. We test free testosterone, estradiol, SHBG, prolactin, and thyroid, then audit medications and stress physiology so we can find the actual brake, not just paper over it.
TL;DR: Low libido is often dismissed as "stress" or "aging," but at Fishtown Medicine, I view it as a key sign. It is a barometer of your hormonal, metabolic, and emotional health. I do not just prescribe a pill. I look for the brakes that are holding you back.
What Causes Low Libido in Men?
Low libido in men is rarely just about testosterone. Testosterone is the fuel, but it is not the only part of the engine. In my Philly practice, I see men with "normal" lab numbers who still feel flat. The reasons usually fall into one of three patterns.
- The testosterone trap. You may have a normal total testosterone level but a high SHBG (Sex Hormone Binding Globulin), a protein that binds testosterone and locks it away so your body cannot use it. The number that actually matters for desire is free testosterone, the unbound portion.
- Estrogen matters in men too. Yes, men need estrogen. If estradiol is too low, often from over-blocking it with anti-estrogen drugs, libido crashes along with mood and joint health.
- The vascular connection. Erection quality is a canary in the coal mine for heart health. If blood flow is poor down there, it is often poor in your heart and brain too. We use this as a screening signal, not just a sex problem.
What Causes Low Libido in Women?
Low libido in women relies on a complex interplay of hormones, nervous system tone, and context. The biology is real, even when the cause looks "lifestyle." Here are the patterns I see most often.
- The ovulation peak. Libido naturally rises around ovulation, when estrogen peaks. If you are on hormonal birth control that suppresses ovulation, that monthly peak disappears, and many women notice a flat baseline.
- Testosterone for women too. Women make and need testosterone, just in smaller amounts than men. Free testosterone supports drive, assertiveness, and clitoral sensitivity.
- The "context" switch. For many women, desire is responsive, not spontaneous. That means desire shows up after arousal begins, not before. Chronic stress (high cortisol) is the ultimate brake. When your nervous system is in fight-or-flight, the reproductive system is the first thing your body shuts down.
How Does Fishtown Medicine Approach Low Libido?
The Fishtown Medicine approach to low libido is to find the specific brake before reaching for a pedal. Most of the time, the brake is a combination of unbalanced hormones, an under-recognized medication side effect, and a stressed nervous system. Here is what we actually do.
- Deep-dive labs. I test free testosterone (the active form), total testosterone, SHBG (Sex Hormone Binding Globulin), estradiol (the main estrogen), prolactin (a pituitary hormone that suppresses libido when high), and a full thyroid panel. For women, we add Day 21 progesterone and DHEA-S (an adrenal precursor hormone).
- Medication audit. SSRIs (a class of antidepressants like Lexapro and Zoloft), certain blood pressure medications, finasteride, and antihistamines are notorious libido killers. We look for alternatives or dose changes when it is safe to do so.
- Stress physiology. I help you map your "accelerators" and "brakes." Sometimes the best aphrodisiac is fixing your sleep and lowering your evening cortisol curve.
- Body composition. Visceral fat (the deep belly fat around organs) converts testosterone into estrogen in men and worsens insulin resistance in both sexes. Resistance training and protein-forward eating change this fast.
- Connection, not just chemistry. When the biology is clear and desire is still off, I refer to a vetted local sex therapist or couples counselor. There is no shame in this. It is often the missing piece.
When Should I See a Doctor for Low Libido?
You should see a doctor for low libido when low desire lasts more than a few months, when it is causing distress for you or your partner, or when it shows up alongside fatigue, mood changes, or erection issues. Specifically, get evaluated if:
- Your morning erections have disappeared (a sign of low free testosterone or vascular trouble).
- Sex is painful (women) or you cannot maintain an erection (men).
- You feel emotionally flat, foggy, or unmotivated alongside the libido drop.
- You started a new medication and noticed the change soon after.
- You and your partner are arguing about it.
Fishtown Medicine
A 90-minute conversation with Dr. Ash. A written plan you can actually follow.
Actionable Steps in Philly
Custom plan for low libido.
- Sleep first. Aim for seven to nine hours. Testosterone is made overnight in men, and progesterone supports sleep in women. Bad sleep tanks both.
- Lift heavy, twice a week. Resistance training raises testosterone and improves insulin sensitivity. Even 30 minutes at a Fishtown gym moves the needle.
- Audit alcohol. More than seven drinks a week reliably suppresses testosterone and disrupts sleep. Try a two-week pause and watch what changes.
- Get the right labs. Ask for free and total testosterone, SHBG, estradiol (sensitive assay), prolactin, TSH, free T3, and ferritin. Women add Day 21 progesterone.
- Have the conversation. Tell your partner what is going on. Schedule low-pressure, non-sexual physical contact (skin to skin, not goal-driven). The nervous system needs safety before desire returns.
Key Takeaways
- Low libido is a signal, not a flaw. It is your body asking for an audit.
- Free testosterone, not total, is what matters. Many men with "normal" total testosterone are actually low on the active form.
- Birth control and SSRIs are common culprits. A medication audit is one of the highest-yield steps.
- Stress is the master brake. Without nervous system safety, no hormone protocol will fully work.
Scientific References
- Travison TG, et al. "The relative contributions of aging, health, and lifestyle factors to serum testosterone decline in men." Journal of Clinical Endocrinology & Metabolism. 2007.
- Davis SR, et al. "Testosterone for low libido in postmenopausal women." NEJM. 2008.
- Khera M, et al. "Adult-onset hypogonadism." Mayo Clinic Proceedings. 2016.
- Reisman Y. "Sexual consequences of post-SSRI syndrome." Sexual Medicine Reviews. 2017.
- Pastuszak AW, et al. "Erectile dysfunction as a marker for cardiovascular disease." Translational Andrology and Urology. 2017.
Related at Fishtown Medicine
- Low Libido (Symptoms) - the broader low-libido workup
- Low Libido in Men - the testosterone-and-sleep workup specific to men
- Hormone Optimization - the service page for hormone-related care
- Perimenopause - the invisible transition that often presents as low desire
Frequently Asked Questions
Common Questions
Deep-Dive Questions
Ready when you are
Dr. Ash reads every intake himself, and answers questions personally - usually within a few hours.





