About
Testosterone
Understand what your testosterone levels mean and how they affect your body.
Low or high levels can impact energy, mood, strength, and overall wellbeing. This guide helps you make sense of your results so you can make more informed decisions about your health and training.
Low or high levels can impact energy, mood, strength, and overall wellbeing. This guide helps you make sense of your results so you can make more informed decisions about your health and training.
AboutTestosterone
Learn to spot the signs of low and high testosterone, from fatigue and slow gains to mood swings and unwanted side effects.
Understand how balanced levels fuel lean muscle development, boost training results, and keep your body functioning at its best. Whether you're training naturally or running a cycle, this is your go-to guide for testosterone health.
What Testosterone does
The hormone behind energy, strength, and recovery.
Testosterone plays an important role in how your body performs day to day. It supports muscle development, energy levels, focus, and recovery.
When your levels are balanced, you’re more likely to feel consistent in your training and overall wellbeing.
When levels are too low, you may notice fatigue, reduced strength, low mood, or slower progress. When levels are too high, it can lead to unwanted side effects and imbalance.
Understanding your testosterone levels helps you see what’s happening in your body, so you can make more informed decisions about your training, recovery, and health.
| Age group | Normal range (Total T) |
|---|---|
| 18-39 years | 10.4 – 34.7 nmol/L |
| 40-59 years | 10.4 –30.9 nmol/L |
| 60+ years | 8.7 – 29.5 nmol/L |
Want to find out how testosterone testing works? Learn more
Signs of Low Testosterone
If your testosterone levels are too low, you might experience:
- Constant tiredness or low energy
- Reduced muscle mass and slower gains
- Decreased libido or erectile dysfunction
- Increased fat storage, particularly around the midsection
- Mood swings, irritability or depression
Signs of High Testosterone
Excessively high testosterone levels can cause problems such as:
- Acne and oily skin
- Increased aggression or emotional instability
- High blood pressure
- Accelerated hair loss (if genetically predisposed)
- Prostate enlargement
Effects on muscle growth
The testosterone levels in bodybuilders can vary significantly depending on whether they are natural (natty) or using anabolic steroids.
Natural Bodybuilders
- Normal natural testosterone levels range between 10.4 – 34.7 nmol/L for men in their prime (18–30 years).
- Elite natural bodybuilders who optimise diet, training, and sleep may reach the upper end of the range (27.7 – 41.6 nmol/L).
- Free testosterone levels typically remain 5 – 25 nmol/L.
Enhanced (Steroid-using) Bodybuilders
- When using testosterone-based anabolic steroids (e.g., Testosterone Enanthate, Cypionate, or Propionate), levels can skyrocket.
- Competitive or professional bodybuilders often maintain 104.0 – 346.7 nmol/L while cycling.
- Free testosterone can also be 10× higher than normal, leading to massive muscle growth but also higher risks of side effects.
| Testosterone Level (nmol/L) | Typical Effects |
|---|---|
| 10.4–20.8 (Low-Normal) | Suboptimal muscle growth, slow recovery, fatigue |
| 20.8–41.6 (High-Normal) | Ideal for natural muscle building, good recovery |
| 41.6–104.0 (Mild Enhancement) | Noticeable muscle gains, faster recovery |
| 104.0–346.7 (Enhanced) | Rapid mass gain, high strength, increased side effects |
| 346.7+ (Extreme Use) | Pro bodybuilder-level mass but severe health risks |
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