Is there a one-word synonym for the bulky description of a product that is "packaged using reduced packaging"? So that one could use the synonym in a sentence like, "This product is xxxx"? I used "reduced packaged" but I am not sure if that's correct.
"This product is sustainably packaged"
Sustainable Packaging — Wikipedia
Sustainable packaging is the development and use of packaging which results in improved sustainability.
This involves increased use of life cycle inventory (LCI) and life cycle assessment (LCA) to help guide the use of packaging which reduces the environmental impact and ecological footprint.
It includes a look at the whole of the supply chain: from basic function, to marketing, and then through to end of life (LCA) and rebirth. Additionally, an eco-cost to value ratio can be useful
The goals are to improve the long term viability and quality of life for humans and the longevity of natural ecosystems.
Posting another answer, based on discussion in comments.
If minimum amount of material is used for its packaging,
"product has minimal packaging",
"product is minimally packaged"
Minimum — M-W
noun the lowest number or amount that is possible or allowed
Or, if it follows the currently trending design philosophy called "minimalism",
"product has minimalist packaging",
"product is minimalistically packaged"
Minimalism — M-W
noun a style or technique (as in music, literature, or design) that is characterized by extreme spareness and simplicity
Read more on Wikipedia. (emphasis mine)
The concept of minimalist architecture is to strip everything down to its essential quality and achieve simplicity. The idea is not completely without ornamentation, but that all parts, details and joinery are considered as reduced to a stage where no one can remove anything further to improve the design.