Like me, if you are trying to reduce your individual impact on the environment by assessing and changing your consumption habits and better manage your waste, I strongly advise you to follow the activities of the Zero Waste Switzerland Association.
The objectives of the association is to support the population in making responsible consumption choices and raise awareness on waste-related challenges in the country through events, guided tours and other workshops in various Swiss cities (and therefore, in different languages). The movement supports for instance shops that encourage customers to buy items in bulk and/or without packaging, or initiatives towards re-using and recycling.
Unfortunately, I haven't seen any planned event to take place in Zug, and I am waiting for a response to know whether there's anyone around the city to answer some questions and, why not, organize a meet-up. If you are reading this article from another country than Switzerland, you should be able to find a local chapter or organization sharing the same values, missions and events where you are (and if not, jump in and start your project!).
Here is the useful thing I wanted to share with you: on the website you will also access the map of Zero Waste friendly shops in the country.
Enter the name of the city where you are interested in and it will point and list the shops that support the movement one way or the other.
In Zug for example, you'll find Vom Fass (the oil and liquor shop in Altstadt) and the Restaurant Grand Café and its Beer Station (to buy beers in reusable carafes). The Brockerhus at the Okihof (second-hand shop of the recycling station) is not listed here, but it is obviously part of the zero-waste concept. And you will find (sadly, obviously) a lot more options in bigger cities like Zurich, included supermarkets where you can buy products in bulk.