Carbohydrates and testosterone
Introduction
Carbohydrates do not directly stimulate testosterone production, but they influence how much testosterone remains available and functional. Carb intake affects cortisol, SHBG, and the stress response to training, which together shape total and free testosterone levels.
How It Works
Carbohydrates ↑ → Glycogen ↑ → Cortisol ↓ → Free Testosterone ↑
Adequate carbohydrates help maintain glycogen stores and reduce cortisol during intensive training, preserving a favorable hormonal environment.
What Science Says
In young, strength-training men consuming adequate calories and protein, varying the carbohydrate-to-fat ratio for 12 weeks did not affect serum testosterone, estradiol, or SHBG.
Adequate carbs during intense training support a favorable hormonal profile. Low-carb diets do not inherently lower testosterone, but they elevate cortisol, worsening the testosterone-to-cortisol ratio.
In short-term studies, high-carbohydrate diets in men increased total testosterone and SHBG while lowering cortisol.
Low-carb diets do not reduce testosterone if protein intake is moderate, but combining low carbs with high protein can substantially decrease total testosterone. They also raise resting and post-exercise cortisol, potentially worsening the hormonal environment in active men.
In small clinical studies, low-carbohydrate diets in men with metabolic syndrome increased testosterone levels and improved erectile function, likely through improved metabolism and reduced body fat.
Risks and Considerations
Very low-carb intake during heavy training increases cortisol and worsens hormonal stress.
Low-carb + high-protein diets may suppress total testosterone.
Sedentary or metabolically unhealthy men may benefit from low-carb diets indirectly through fat loss.
Context (training load, calories, protein intake, metabolic health) matters more than carb percentage alone.
What’s Next
Want to learn more about nutrition? Check our in-depth articles:
→ Nutrition Overview: How Diet Affects Testosterone Levels
→ Protein and Testosterone
→ Fats and Testosterone