Which would you say has the greatest effect on boosting testosterone naturally?

Type 1, 2, 3, 4 or 5 below.
1. Proper nutrition and getting down to a lean state.
2. Supplements that fix any nutritional deficiencies you may have: zinc, vitamin D, magnesium, etc.
3. Adequate recovery/sleep
4. Training
5. Supplements that optimize your body's own systems first (gut health, insulin, etc.)