To make sure we’re all on the same page, we should clarify the terminology, since it’s admittedly a little confusing if you’re new to it.
Then, there’s the fictional Soylent that it’s named after. While many people assume it’s named after the Soylent Green product in the movie of the same name. However, it’s actually named after the Soylent product in the book Make Room! Make Room!
Then there’s the term “soylent” (with a lower-case s). As a company, Rosa Labs is ok with, even encourages, do-it-yourself (DIY) versions to be created by others. Rather than try to control the term “soylent”, they went ahead and embraced soylent being a generic trademark, so when talking about similar products people don’t have to use a different term like “nutritionally complete meal replacement” or the like.
There have been meal-replacement products around far longer than the recent crop of products. The real difference between those and the soylent-type products is the viability of having them be your sole source of nutrition.
Existing meal replacement products tended to be designed for replacing one or maybe two meals a day. They often had too few calories and too much sugar to be considered nutritionally complete on their own, and for that target use case, they were fine.
The ‘soylent’ concept differs in it first-and-foremost being a viable choice as your sole source of nutrition. Not each of them will target the same set of macronutrients or micronutrients, but they can absolutely be the only thing you ingest each day to get you all the protein, fat, carbohydrates, vitamins, and minerals you need.
They intentionally differ on things like macronutrient ratios. The ones I prefer for myself, for instance, are ketogenic with very few carbohydrates, adequate protein, and high fat content, as those have helped me preserve muscle tissue during my weight loss.
Outside of the thousands of DIY recipes that already exist, there are many commercial soylent options as well. Fortunately we already have sites like BlendRunner to help provide a comparison of the available options, and a list of current commercial distributors available on the soylent subreddit.
When looking at potential soylent products, whether you’re looking at DIY options or to use a commercial one, it’s definitely recommended to try finding some small sample sizes to find ones that you enjoy the taste of, are in the right price range for you, and have the nutritional content you’re looking for.