Ingredient file // Ingredient
L-Tryptophan
An added form of the essential amino acid tryptophan.
Our read // In our catalog
In 1 of every 24 foods we track
Share of foods that list it
4%
107 of the 2,595 foods with an ingredient list on file, from 17 brands. 95 dry dog food, 9 wet dog food, 3 dog food topper.
Each square is 1% of the catalog
Where it sits on the label
Median position 26. In the top five of 0 foods, so it is usually a minor ingredient.
Above the salt
Usually listed after the salt, which caps it at roughly 1% of the recipe in 93% of foods.
Price per lb
Median of the cheapest bag price across 88 priced foods, 10% below the catalog. The price is the food's, not the ingredient's.
Who leans on it
18%
of the foods that list it are from Fromm. 17 brands use it in total.
What it is
Why it turns up in dog food
- The precursor the body uses to make serotonin, which is why it appears in recipes aimed at calm behavior.
Who uses it
Brands, best sellers and the company it keeps
Top brands, by foods that list it
Plus 7 more brands.
Amazon best sellers that list it
- #12 Pedigree Adult Grilled Steak & Vegetable Flavor Dry Dog Food
- #22 Cesar Filet Mignon Flavor & Spring Vegetables Garnish Dry Dog Food
- #41 Pedigree Small Dog Grilled Steak and Vegetable Flavor Dry Dog Food
- #73 Pedigree Puppy Chicken & Vegetable Flavor Dry Dog Food
- #87 Iams Adult Healthy Weight Dry Dog Food
Rank on Amazon's dog food best seller list, checked October 2026.
Usually listed with, share of the foods that list it
- Natural Flavor 54%
- Chicken Fat 43%
- Chicken 37%
- Brown Rice 36%
- Chicken Meal 31%
- Dried Plain Beet Pulp 31%
- Brewers Rice 31%
- Chicken By-Product Meal 30%
- Corn Gluten Meal 26%
- Soybean Meal 21%
- Oatmeal 21%
- Flaxseed 21%