It has added vitamins and minerals, so you should be getting enough. I would say do not take the multivitamin because it is unnecessary, and you might accidentally get megadoses of certain things. Further, scientific research does not support using a multivitamin. However, if you have a history of being vitamin D deficient, definitely continue to supplement with that. This product uses vitamin D2 so it can’t be vegan, and I believe it was formulated assuming that you would absorbs some from sunlight. Many foods are fortified with this form of vitamin D in the United States. If you don’t absorb it well from sunlight, and you weren’t getting enough in your diet before, that probably won’t change. They can tell from your blood work if you are getting to much. If it shows in your blood work that you are getting to much, you can stop supplementing or lower your dose. However, because this is a fat soluble vitamin, if you stop supplementing now, you could potentially deplete your stores. You don’t have to constantly be worried about it because apart from bloodwork, you can experience other symptoms of nutrient deficiency. You’ll probably be getting a more balanced diet when you eat Huel than you would if you were balancing the meals yourself. People keep talking about balance over time, but the truth is that because you like certain recipes and food, you are likely to continue leaving now certain vitamins and minerals over an extended time. People who balance their own meals get nutrient deficiencies all the time. Some people might say that if you had variety and your diet, this would not happen, but that is really hard and costly to do for a lot of people.