1. Vitamin D
Vitamin D is one of the most popular vitamins and supplements that people take, because it has many benefits and can help several bodily functions.
"Vitamin D plays a role in insulin sensitivity, inflammation regulation, and muscle function, all of which become increasingly important for weight management after 40," says dietitian Kathleen Benson, CSSD, CPT, RDN at VNutrition. "Low vitamin D status is common in this age group and has been associated with higher body fat and reduced metabolic efficiency. While supplementing vitamin D does not directly cause weight loss, correcting a deficiency may remove a physiological barrier that makes weight loss more difficult."
2. Magnesium
People often associate magnesium with relaxing their muscles and helping them sleep. Still, it can also contribute to weight loss in some cases when paired with a healthy, balanced diet and exercise.
"Magnesium supports blood sugar regulation, nervous system function, sleep quality, and muscle recovery," notes Benson. "Inadequate magnesium intake has been linked to insulin resistance, higher stress levels, and poorer sleep, which can indirectly interfere with weight loss efforts. More bioavailable forms, such as magnesium glycinate or bisglycinate, are generally better tolerated and less likely to cause digestive side effects. Supporting an adequate magnesium status may help improve blood sugar control and recovery, making it easier to maintain consistent nutrition and exercise habits."
3. Creatine Monohydrate
While this might be considered more a supplement than a vitamin, Benson adds that it's still a smart supplement that people over 40 can take to stay in better shape.
"Creatine does not directly cause weight loss, and research does not support it as a fat-loss supplement," she notes. "However, creatine has well-established benefits for muscle performance and strength, with emerging evidence supporting benefits for cognitive function, particularly as we age. By supporting training capacity, lean mass retention, and mental energy, creatine may indirectly support weight management through improved performance and adherence to helpful lifestyle behaviors."
As usual, before you begin taking any new vitamin or supplement, it's a wise idea to speak with your healthcare provider about whether or not taking these is a good choice for you and your personal health history.
"Supplements should be personalized and cleared with a healthcare provider when possible," says Benson. "None of these supplements replace foundational habits like adequate protein intake, resistance training, sleep, and stress management, but they may support those behaviors when deficiencies or age-related changes are present."