Testosterone Replacement Therapy: Comprehensive Explanation & What You Need to Know (For Both Men and Women)

When most people think of testosterone, they think of sex drive, muscle growth, or maybe a commercial aimed at middle-aged men—but the truth is, testosterone plays a critical role in how both men and women feel, move, recover, and show up in life.

As a coach who's worked with tactical professionals, first responders, postpartum moms, and overtrained athletes, I’ve seen firsthand how symptoms of low testosterone are often brushed off as "normal aging" or overtraining—when really, they’re a sign your body is underperforming and under-nourished.

Unfortunately there is a lack of education on what hypogonadism (low-T) and what TRT really is and how it actually helps. It's not as simple as talking to an online doctor who prescribes it to you after reviewing your 5 question survey. If your body is not producing adequate hormones - something is SERIOUSLY wrong and your body deserves more depth and respect than that.

In this post, I’m breaking down what testosterone actually does in the body, signs that something might be off, what labs you should look into, how TRT can help (and when it might not), and the root causes that need to be addressed whether or not you go the replacement route.

How Testosterone Works in the Body

Testosterone is a steroid hormone primarily produced in the testes for men and the ovaries and adrenal glands for women. It plays a vital role in regulating:

  • Muscle protein synthesis (muscle growth and recovery)

  • Red blood cell production (oxygen delivery and endurance)

  • Bone density and joint health

  • Libido and sexual function

  • Motivation, mood stability, and confidence

  • Cognitive function and memory

In men, testosterone production is governed by the hypothalamic-pituitary-gonadal (HPG) axis. The hypothalamus releases GnRH, which signals the pituitary gland to release LH and FSH. LH then stimulates the Leydig cells in the testes to produce testosterone.

In women, although testosterone levels are lower, it is still critical for maintaining energy, libido, and muscle mass. Women produce testosterone in smaller amounts from the ovaries and adrenal glands, and it's also a precursor to estrogen production.

As people age—or due to stress, under-eating, overtraining, TBI's, or endocrine disruption—testosterone production can decline, leading to a wide range of symptoms.

Common Signs of Low Testosterone

In Men:

  • Decreased libido or erectile dysfunction

  • Loss of muscle mass or strength

  • Increased body fat, especially around the belly

  • Chronic fatigue or brain fog

  • Mood changes: irritability, anxiety, or depression

  • Poor recovery from workouts

  • Low motivation or drive

In Women:

  • Low libido and vaginal dryness

  • Trouble building or maintaining muscle

  • Fatigue and low mood

  • Increased fat storage, especially in the hips and abdomen

  • Sleep disturbances or hot flashes

  • Decreased confidence or emotional resilience

These symptoms often overlap with other hormonal imbalances (thyroid, cortisol, estrogen), so a full assessment is key before jumping straight into treatment.

Types of Hypogonadism

Before starting TRT, it's important to understand why testosterone may be low in the first place. There are two primary types of hypogonadism:

Primary Hypogonadism (Testicular Failure)

This occurs when the testes (or ovaries in women) do not produce adequate amounts of testosterone despite being properly stimulated. In this case, LH and FSH levels are typically elevated as the body tries to signal more production. Causes include:

  • Genetic conditions (e.g., Klinefelter syndrome)

  • Injury or trauma to the gonads

  • Chemotherapy or radiation

  • Infections 

  • Autoimmune diseases

Secondary Hypogonadism (Pituitary or Hypothalamic Dysfunction)

Here, the issue lies in the signaling centers—the hypothalamus or pituitary gland—which fail to stimulate the gonads. This leads to low LH/FSH and low testosterone. Causes include:

  • Pituitary tumors or damage

  • Chronic stress

  • Severe under-eating or overtraining

  • Opioid use

  • Anabolic steroid use and subsequent suppression

  • Traumatic Brain Injury (TBI)

Identifying the type of hypogonadism is crucial for selecting the right treatment path. For example, some men with secondary hypogonadism may benefit from medications like clomiphene or HCG instead of traditional TRT.

Labs to Request Before Starting TRT

If you're suspecting low testosterone, here are labs to look into for a full-picture view:

Hormone Panel:

  • Total and Free Testosterone

  • SHBG (Sex Hormone Binding Globulin)

  • Estradiol (especially important to monitor for men on TRT)

  • DHEA-S

  • LH/FSH (helps determine if the cause is primary or secondary hypogonadism)

Additional Labs:

  • TSH, Free T3, Free T4 (Thyroid function)

  • Salivary Cortisol (stress hormones and adrenal health)

  • Lipid panel (TRT can impact cholesterol)

  • Hematocrit/Hemoglobin (to monitor for thickened blood)

  • Vitamin D, B12, Magnesium, and Zinc (nutrients essential to hormone production)

What TRT Can Do

TRT when medically supervised and appropriately dosed, can lead to significant improvements in:

  • Energy and stamina

  • Sexual function

  • Lean muscle mass

  • Mental clarity and confidence

  • Bone density

  • Motivation and resilience

It’s not a magic fix—but it can be life-changing when used alongside lifestyle changes and proper supplementation.

Types of TRT and What to Watch For

There are several forms of testosterone replacement therapy, and the best choice depends on your lifestyle, absorption, and lab responses. Here's a breakdown:

Common Types of TRT:

  • Injectable Testosterone (Cypionate or Enanthate): Most commonly prescribed, typically administered weekly or biweekly. Delivers a reliable and controlled dose but can cause peaks and valleys in mood or energy if not dosed appropriately.

  • Topical Gels or Creams: Applied daily to the skin; "convenient" but absorption rate and effectiveness varies widely. 

  • Pellets: Implanted under the skin and last 3-6 months. Low maintenance but harder to adjust dosing.

  • Oral/Buccal Tablets: Less commonly used due to liver metabolism and lower bioavailability.

How to Know You're Underdosed or On Poor Quality TRT:

  • You feel no improvement after 4–6 weeks

  • Your bloodwork shows low or borderline total/free testosterone

  • Your estradiol levels are crashing or spiking out of range

  • You experience mood instability, worsening libido, or increased fatigue

  • Injection site pain, inflammation, or allergic reactions (often due to poor carrier oils or compounding practices)

Signs Your Protocol May Need Adjusting:

  • You're being given the same dose regardless of lab results, symptoms, or body weight

  • Your provider isn’t testing estradiol, SHBG, or hematocrit regularly

  • You feel great for a couple days after injections, then crash—this could indicate too long between doses or improper formulation

Poor-quality TRT from mail-order clinics or underqualified providers is a growing problem. You should always feel informed, empowered, and monitored. If something feels off—don’t ignore it.

Work On The Root Cause

Many cases of “low T” are the result of deeper issues—like chronic stress, under-eating, overtraining, brain injury, or inflammation. Before or alongside TRT, consider supporting the body with:

Foundational Supplements:

  • Zinc – critical for testosterone production

  • Magnesium – supports sleep, stress response, and hormonal function

  • Vitamin D – acts as a hormone and supports immune/testosterone balance

  • Ashwagandha – adaptogen that can reduce cortisol and boost T

  • Tongkat Ali or Fadogia Agrestis (with caution and under guidance)

Lifestyle Non-Negotiables:

  • Eat balanced macronutrients

  • Prioritize sleep quality and circadian rhythm with meal timing

  • Manage stress

  • Lift HEAVY, but don’t overtrain

  • Avoid alcohol and seed oils as much as possible

Important Notes on TRT

  • TRT is not just a men's-only treatment—women may benefit too, especially in perimenopause or post-hysterectomy

  • It should never be started without labs and should always be monitored by a qualified provider

  • Always work on fixing underlying dysfunctions (thyroid, stress, nutrition) before or alongside TRT

  • It’s not about chasing “high T” levels—it’s about restoring balance

TRT is a powerful tool that can help you feel like yourself again. But if prescribed inappropriately and without looking at the bigger picture, it can do more harm longterm.

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