Absolutely. You get some Tryptophan from your food everyday but in low quantities (i.e. a Banana has 10 mg of Tryptophan), and most of the time it competes with other amino acids vying for biosynthesis in your digestion system.
Natural sources of Tryptophan Pumpkin seeds, soy, some seafood are actually better natural sources of Tryptophan than real Turkey (and other poultry), but again the amounts are quite low, around .2 g/100g of food.
Putting it simply, to get as much Tryptophan as there is in Turkey Sleep, would require you to 3 oz of turkey. And that’s not including the low absorption rate of Tryptophan from food which has other amino acids, which compete for the same synthesis pathway, known as the Tryptophan Paradox.
As one of the nine essential amino acids, L-Tryptophan is vital to your health and quality of life, regardless of whether you take Turkey Sleep or not. There is a growing body of evidence suggesting that because of our modern diet, low levels of Serotonin and Melatonin may simply be due to our lower Tryptophan consumption and conversion.