Does anyone know of a trustworthy source of "lab tested" organic papaya leaf powder that is available in the US? Natural supplements are not regulated. You don't know for sure what you are getting. Many sources are from India and have the organic logo on them, but I don't assume that that is proof of the product actually being organic.
Here is an important article (NY Times 2015) that explains that many herbal supplements on your grocery shelf can contain smaller amounts, or even none, of the product that it is sold as.
What’s in Those Supplements?
"The New York State attorney general’s office accused four national retailers on Monday of selling dietary supplements that were fraudulent and in many cases contaminated with unlisted ingredients.
The authorities said they had run tests on popular store brands of herbal supplements at the retailers — Walmart, Walgreens, Target and GNC — which showed that roughly four out of five of the products contained none of the herbs listed on their labels. In many cases, the authorities said, the supplements contained little more than cheap fillers like rice and house plants, or substances that could be hazardous to people with food allergies."
Yet another question 
Frivolous non-medical question! 
Question about lymph nodes 
To treat or not to treat, that is the question..
