Which supplement works better to improve running performance: creatine monohydrate or tryptophan?

Ratings at a Glance

Supplement	Effectiveness Rating	Confidence Rating
Creatine Monohydrate
Tryptophan

Effectiveness Rating: Creatine Monohydrate vs Tryptophan

The effectiveness rating is a measure of the supplements' ability to improve running performance. This rating answers the question of whether or not a supplement does what it claims. Both creatine monohydrate and tryptophan have good (but not great) evidence showing they may be able to improve running performance. Both supplements should provide some positive results.

Confidence Rating: Creatine Monohydrate vs Tryptophan

Another factor to take into account when comparing supplements is the confidence rating. This rating is a measure of how valid each supplement's effectiveness rating is. Remember, the confidence rating is a measure of how much you can trust the effectiveness rating. This rating is based on how many studies are included in the database on a supplement's claims. Ideally, you want a high effectiveness AND confidence rating.

Both creatine monohydrate and tryptophan have low confidence ratings. This means neither supplement has an adequate amount of research to back up this claim. A low confidence rating questions the validity of the effectiveness rating.