Why Is My Testosterone Low? Research-Backed Causes (Including Prolactin, Sleep, Stress, and Environmental Exposures)

If you're wondering why your testosterone is low, you're not alone and you're not imagining it. Testosterone can affect energy, mood, motivation, libido, strength, sleep, and body composition. But low testosterone isn't always a standalone diagnosis. Often, its a signal that something upstream is affecting the brain hormone testes communication loop.

If you want the simple physiology first, start here: How Testosterone Negative Feedback Works in Men (hypothalamus  pituitary  testes  adrenal glands): https://www.vitalpathmedicinellc.com/blog/categories/mens-hrt

The most common (and most fixable) reasons testosterone runs low

1) Poor sleep and sleep apnea

Sleep is one of the strongest, most consistent drivers of healthy testosterone production. Short sleep, fragmented sleep, and untreated obstructive sleep apnea (OSA) can all be associated with lower testosterone and worse symptoms.

Practical takeaway: If you snore, wake up unrefreshed, or feel excessively sleepy during the day, its worth discussing OSA screening with your clinician.

2) Weight gain, insulin resistance, and metabolic health

Higher body fat (especially visceral fat) and insulin resistance are commonly associated with lower testosterone. This can become a cycle: lower testosterone may make it harder to maintain muscle and energy, which can worsen metabolic health over time.

3) Alcohol and substance effects

Regular heavy alcohol intake can impair hormone signaling and increase the likelihood of nutrient deficiencies and sleep disruption all of which can worsen testosterone-related symptoms.

4) Medications that can lower testosterone

Some medications can lower testosterone directly or indirectly. Examples include:

·         Opioid pain medications

·         Long-term or frequent glucocorticoids (steroids)

·         Some psychiatric medications (varies by medication and person)

Practical takeaway: Don't stop medications on your own, but do ask whether a medication could be contributing.

5) Under-eating, overtraining, and chronic stress load

Severe calorie restriction, rapid weight loss, or excessive training without adequate recovery can signal the body to conserve energy. In some men, that can show up as lower testosterone and lower libido.

Pituitary causes you don't want to miss (including prolactin)

6) High prolactin (hyperprolactinemia)

Prolactin is a hormone made by the pituitary gland. When prolactin is elevated, it can interfere with the signals that support testosterone production.

Common reasons prolactin can be high include:

·         Medication effects (a frequent cause)

·         Hypothyroidism (low thyroid function)

·         Pituitary tumors called prolactinomas (usually benign)

Why this matters: If prolactin is significantly elevated, it can contribute to low testosterone, sexual dysfunction, and sometimes symptoms like headaches.

When to take pituitary concerns seriously (red flags)

This is not meant to diagnose anythingbut its reasonable to seek prompt medical evaluation if low testosterone is paired with concerning symptoms such as:

1.      New or severe headaches

2.      Vision changes (especially loss of peripheral vision)

3.      Unexplained nipple discharge

Chronic illness and inflammation

7) Medical conditions that can suppress testosterone

Testosterone can be lower in the setting of chronic medical conditions, including poorly controlled diabetes, significant systemic inflammation, and other illnesses. Sometimes the body is prioritizing survival and stability over reproduction-related hormone signaling.

First responders and shift workers: why low testosterone can be more common

If you're a first responder or you work rotating shifts, low testosterone symptoms can be more common for a few research-supported reasons:

·         Circadian rhythm disruption (your body clock is constantly being reset)

·         Sleep debt and fragmented sleep

·         Higher rates of stress exposure and burnout

·         Higher risk of weight gain and sleep apnea in some shift-work patterns

Practical takeaway: In this group, addressing sleep quality and recovery often has outsized benefits.

Environmental exposures: what's more strongly supported

8) Endocrine-disrupting chemicals (EDCs)

Some environmental chemicals can interfere with hormone signaling. The most commonly discussed categories include:

·         Phthalates (often found in fragrances and some plastics)

·         Bisphenols (like BPA, found in some plastics and can linings)

Research context: The evidence is stronger that these exposures can affect hormone signaling at a population level than it is for proving a single product caused low testosterone in one individual. Still, many clinicians consider it reasonable to reduce exposure when possible.

Low-drama ways to reduce exposure:

1.      Avoid microwaving food in plastic

2.      Choose fragrance-free when feasible

3.      Use glass or stainless steel for hot foods/liquids

Food and testosterone: what people worry about (and what we actually know)

Many men ask about hormones in food especially dairy, meat, and highly processed foods.

Here is the honest, research-based answer:

·         There are theories that certain food exposures could influence hormones.

·         There are also plausible indirect pathways (for example, ultra-processed diets affecting weight, insulin resistance, sleep, and inflammation which can then affect testosterone).

·         But when it comes to proving that a specific food source is directly lowering testosterone in most individuals, we don't have definitive, one-size-fits-all evidence at this time.

Practical takeaway: A food conversation is still worth having, but it should be framed around what is most consistently supported: metabolic health, protein intake, fiber, sleep, and reducing ultra-processed foods.

Labs that help clarify the why (not just the number)

A useful evaluation often looks beyond total testosterone alone. Depending on your symptoms and history, clinicians may consider:

1.      Total testosterone (ideally a morning draw)

2.      Free testosterone (or a method to estimate it)

3.      SHBG

4.      LH and sometimes FSH

5.      Prolactin

6.      Thyroid labs (TSH, sometimes free T4)

7.      Metabolic labs (A1c, lipids)

8.      CBC/hematocrit (important for safety if treatment is considered)

If you want a straightforward explanation of the #1 safety lab we monitor with testosterone treatment, read: https://www.vitalpathmedicinellc.com/post/cbc-hematocrit-on-testosterone-why-it-s-the-1-safety-lab-and-what-high-levels-can-mean

Next step: get a personalized plan

If youre experiencing low libido, fatigue, low motivation, reduced strength, or stubborn body composition changes, a targeted evaluation can help clarify whether testosterone is part of the pictureand what else may be contributing.

Browse more Men's HRT education here: https://www.vitalpathmedicinellc.com/blog/categories/mens-hrt Schedule your FREE discovery call here: https://www.vitalpathmedicinellc.com/schedule-visit

Educational content only. Not medical advice. For personalized recommendations, consult your licensed clinician.

Sara Levin, NP-C is the owner and medical director of Vital Path Medicine, a virtual practice serving patients in AZ,CO,FL, IA,MA,NM,NV, OR,UT,DC. She has 15+ years of experience in ER, urgent care, functional medicine, and medical weight loss. Learn more at Vital Path Medicine https://www.vitalpathmedicinellc.com/