At a glance: Low testosterone (low T) affects energy, muscle mass, mood, and body composition in men of all ages. Testosterone replacement therapy (TRT), including pellet therapy, can restore hormone levels to a normal range when clinically indicated. At OC Weight Loss & Med Spa in Mission Viejo, CA, candidacy is confirmed through blood work and a medical evaluation. Results vary, and treatment carries real risks that are reviewed at consultation.
Medically reviewed by the clinical team at OC Weight Loss and Med Spa. Last updated: June 12, 2026.
What Is Low Testosterone?
Testosterone is the primary androgen hormone in men. It regulates muscle growth, bone density, red blood cell production, fat distribution, and mood. Levels peak in early adulthood and decline gradually — typically about 1 percent per year after age 30. When levels fall below the clinically accepted normal range, or when a man experiences symptoms consistent with deficiency, a provider may diagnose hypogonadism (low T).
Common symptoms include:
- Persistent fatigue that does not resolve with adequate sleep
- Reduced muscle mass and strength despite consistent exercise
- Increased abdominal fat without significant dietary changes
- Low libido and changes in sexual function
- Mood changes including irritability, low motivation, or depressed mood
- Cognitive fog and difficulty concentrating
Symptoms alone are not sufficient for a diagnosis. A blood test measuring total (and often free) testosterone is required. Other conditions can mimic these symptoms, so a thorough evaluation is important before starting any hormone therapy.
How Testosterone Replacement Therapy Works
Testosterone replacement therapy (TRT) works by supplementing the body’s own testosterone production to bring levels back into a healthy physiological range. There are several delivery methods, each with different profiles for convenience, dosing frequency, and hormone stability.
Pellet Therapy
Pellet therapy involves the subcutaneous insertion of small, compressed testosterone pellets — roughly the size of a grain of rice — under the skin of the hip or buttock. The pellets dissolve gradually, releasing a steady, low-level stream of testosterone over approximately three to six months. Because the release mirrors the body’s natural rhythm, many patients experience more consistent hormone levels compared to injections or gels, which can produce peaks and troughs.
Injections and Topical Preparations
Intramuscular or subcutaneous injections are typically administered every one to two weeks. Transdermal gels and creams are applied daily. These options offer flexibility in dosing and are appropriate for patients who prefer not to undergo the pellet insertion procedure. The right format depends on individual lifestyle, tolerance, and clinical response — a decision made in partnership with your provider.
What Patients Typically Experience
In clinical studies, men with confirmed low testosterone who receive TRT commonly report improvements in energy, libido, mood, and body composition over the course of several weeks to months. Muscle gains are typically modest and depend heavily on diet, exercise, and baseline fitness. Fat reduction, particularly around the abdomen, is a frequently reported secondary benefit when hormone levels normalize.
Individual results vary. TRT is not a substitute for healthy lifestyle habits, and response depends on the degree of deficiency, age, overall health, and adherence to treatment. Symptom improvement is usually gradual rather than immediate.
Safety, Side Effects, and Who Should Not Use TRT
Testosterone replacement therapy is a medically regulated treatment with a well-documented safety profile when properly supervised. Patients and providers must weigh benefits against potential risks before beginning treatment.
Common side effects include:
- Acne or oily skin
- Fluid retention
- Increased red blood cell count (polycythemia), which requires periodic monitoring
- Testicular atrophy and reduced sperm production (relevant for men considering future fertility)
- Conversion of testosterone to estradiol, which may cause breast tenderness or mood changes if not monitored
TRT is generally not appropriate for men who:
- Have or are suspected of having prostate or breast cancer
- Have untreated severe obstructive sleep apnea
- Have significantly elevated hematocrit levels
- Are actively trying to conceive (TRT suppresses natural testosterone and sperm production)
- Have uncontrolled heart failure or recent cardiovascular events (consult a cardiologist first)
Candidacy, monitoring protocol, and treatment duration are determined by the medical provider at consultation. Ongoing lab work — typically every three to six months — is a standard part of supervised TRT care.
Frequently Asked Questions
How do I know if my testosterone is actually low?
The only reliable way to confirm low testosterone is through a blood test. Total testosterone is the standard first measure; free testosterone may also be checked. Symptoms such as fatigue or low libido can have many causes, so lab confirmation is essential before attributing them to hormone deficiency.
How soon can I expect to feel a difference?
Most men notice early improvements in energy and mood within four to six weeks. Changes in body composition — increased lean mass and reduced fat — typically take three to six months and are more pronounced with consistent exercise and a balanced diet. Individual timelines vary.
Is pellet therapy painful?
The insertion site is numbed with a local anesthetic before the procedure. Most patients describe minor pressure but no significant pain during insertion. Some temporary soreness or bruising at the site is common in the first few days. There is minimal downtime, and patients can typically resume normal activities the same day with minor restrictions on strenuous activity for a short period.
Does TRT cause prostate cancer?
Current evidence does not support a causal link between TRT administered within normal physiological ranges and the development of prostate cancer. However, TRT is contraindicated in men with known or suspected prostate cancer, and prostate-specific antigen (PSA) is typically monitored during treatment. This topic should be discussed thoroughly with your provider at consultation.
Can I stop TRT once I start?
Yes, TRT can be discontinued. However, stopping may cause testosterone levels to fall below baseline for a period — particularly after extended use — as the body’s natural production has been suppressed. A provider will guide a structured approach to discontinuation when appropriate, which may include medications to stimulate natural production.
Take the Next Step at OC Weight Loss & Med Spa
If you are experiencing symptoms of low testosterone and want to understand whether TRT is appropriate for you, the team at OC Weight Loss & Med Spa in Mission Viejo, CA can help. A free consultation includes a review of your symptoms and a referral pathway for blood work to confirm or rule out hormone deficiency. Treatment, if indicated, is supervised by our medical team under the oversight of Dr. Nezar Dahdal, MD. Reach us at (949) 416-0950 or through our contact page.
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