What Supplements Should Not Be Taken Together

About supplements

Supplement category

  • Multivitamins: These supplements typically contain a combination of essential vitamins and minerals to support overall health and fill any nutritional gaps in the diet. Vitamins are essential nutrients required in small amounts for various physiological functions in the body. Depending upon their soluble content, they may be roughly divided into two distinct categories: water-soluble vitamins and fat-soluble vitamins
  • Omega-3 Fatty Acids: Omega-3 supplements are often derived from fish oil or algae and provide essential fatty acids like EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid), which are beneficial for heart health, brain function, and inflammation management
  • Probiotics: Probiotic supplements contain live beneficial bacteria that help maintain a healthy balance of gut flora, support digestion, and boost the immune system
  • Protein pills: Athletes trying to boost their protein consumption, players, muscle builders, and others frequently utilize these dietary supplements.1 They can come in the form of whey, casein, soy, or plant-based proteins
  • Calcium and Vitamin D: Calcium and vitamin D supplements are often taken to support bone health, especially for individuals at risk of osteoporosis or those with a deficiency in these nutrients.
  • Iron: Iron supplements are frequently used to address iron deficiency anemia, particularly in individuals who have difficulty obtaining sufficient iron through diet alone
  • Vitamin B Complex: B vitamins play a crucial role in energy production, nerve function, and red blood cell formation. B complex supplements contain a combination of B vitamins such as B1, B2, B3, B6, B9 (folate), and B12
  • Herbal and Botanical Supplements: These supplements are derived from plants and may include herbs, roots, flowers, or other botanical sources. Examples include ginseng, turmeric, echinacea, and garlic, which are believed to offer various health benefits
  • Antioxidants: Antioxidant supplements, such as vitamins C and E, selenium, and coenzyme Q10, help combat the damaging effects of free radicals and may have anti-aging and disease-prevention properties
  • Sports Performance Enhancers: These supplements are specifically designed to enhance athletic performance, increase endurance, or improve muscle growth. Examples include creatine, beta-alanine, and branched-chain amino acids (BCAAs)2

Please note that while supplements can be beneficial in certain cases, it's important to consult with a healthcare professional or a registered dietitian before starting any new supplementation regimen to ensure it aligns with your individual health needs and goals

Importance of supplements

Supplements can play a role in supporting overall health and filling potential nutrient gaps in certain situations. Here are some reasons why supplements may be important:

  • Supplements can fill nutrient gaps when dietary intake is insufficient
  • They help address specific deficiencies, promoting overall health and well-being
  • Some medical conditions or life stages require increased nutrient support, which supplements can provide
  • Vegan and vegetarian diets may need supplementation to meet certain nutrient needs
  • Sports supplements aid in performance, muscle recovery, and athletic goals
  • Supplements offer convenience and accessibility for busy lifestyles and limited food access
  • During pregnancy or aging, supplements can support special nutritional requirements
  • Consultation with a healthcare professional is crucial to ensure safe and appropriate supplementation

What supplements should not be taken together?

What will be the interactions? 

Certain supplements may interact with each other, affecting their absorption, effectiveness, or even causing adverse effects. It's essential to be cautious when combining supplements and to seek advice from a healthcare professional or registered dietitian to ensure safety and efficacy. Here are some examples of supplements that should be avoided together or used with caution:

  • Iron and Calcium: Calcium can inhibit the absorption of iron, so it's generally recommended to take iron supplements separately from calcium-rich foods or calcium supplements. However, vitamin C can enhance iron absorption, so taking vitamin C with iron can be beneficial
  • Zinc and Copper: High doses of zinc can interfere with copper absorption, and vice versa. Balancing the intake of these minerals is crucial to maintaining optimal health
  • Vitamin D and Magnesium: Excessive magnesium intake can reduce the effectiveness of vitamin D supplements. It's essential to find the right balance when taking these two supplements together
  • Vitamin K and Blood Thinners: If you are taking blood-thinning medications (anticoagulants), consult with your healthcare provider before supplementing with vitamin K, as it may interfere with the medication's effects
  • Ginkgo Biloba and Blood Thinners: Ginkgo biloba may increase the risk of bleeding when taken with anticoagulant medications
  • Ginseng and Stimulants: Ginseng supplements may interact with stimulants or caffeine, leading to increased heart rate or nervousness
  • Melatonin and Sedatives: Melatonin is a popular supplement used for sleep support, but it can interact with sedative medications or alcohol, causing excessive drowsiness
  • Vitamin E and Blood Thinners: High doses of vitamin E may enhance the effects of anticoagulant medications, leading to an increased risk of bleeding
  • Beta-Carotene and Smoking: Beta-carotene supplements have been associated with an increased risk of lung cancer in smokers or individuals with a history of heavy smoking

Always inform your healthcare provider about any supplements you are taking or planning to take, especially if you are on prescription medications or have underlying health conditions. They can guide you on the appropriate dosages and potential interactions to ensure your safety and well-being.

Risk of taking too many supplement

  • Mega-dosing on individual vitamins or minerals can upset the delicate balance of nutrients in the body
  • High levels of fat-soluble vitamins (A, D, E, and K) can accumulate in the body and cause toxicity over time
  • Some supplements can interact with medications, leading to adverse reactions or reduced effectiveness
  • Taking multiple supplements increases the risk of unintentional overdosing or exceeding recommended daily intakes
  • People with severe overdoses may develop coma, low blood pressure, liver failure, lung injury, and death3

How many supplements can I take at the same time? 

The number of supplements you can take at the same time depends on your individual health needs and recommendations from a healthcare professional. Consult with a healthcare professional or registered dietitian to determine the appropriate number of supplements based on your specific needs and health goals.

  • Avoid unnecessary supplementation and prioritize obtaining nutrients from a balanced diet
  • Consider combination products that provide multiple nutrients in a single dose
  • Start with one supplement at a time and monitor how your body responds before introducing additional supplements

Supplements that are best to take at night

  • Magnesium: Magnesium supplements are often taken at night as they can promote relaxation, improve sleep quality, and help with muscle recovery and relaxation
  • Melatonin: Melatonin is a hormone that regulates sleep-wake cycles.4 Taking melatonin as a supplement before bedtime can be beneficial for individuals with sleep difficulties or jet lag
  • L-theanine: L-theanine is an amino acid found in tea leaves, known for its calming effects. It can be taken at night to support relaxation and better sleep quality
  • Herbal Sleep Formulas: Various herbal blends specifically formulated to promote sleep, such as chamomile, valerian root, passionflower, and lavender, are often taken as supplements at night
  • Collagen: Collagen supplements are sometimes taken before bed as they can aid in tissue repair and recovery during sleep

Supplements that are best to take in the morning

  • Vitamin B complex: B vitamins, such as B12 and B6, are known for their energy-boosting properties. Taking a B complex supplement in the morning can help support energy production throughout the day
  • Vitamin C: Vitamin C is an antioxidant that supports the immune system and aids in collagen synthesis. Taking it in the morning can provide a boost to the immune system and support overall vitality
  • Iron: Iron is an essential mineral involved in the production of red blood cells and oxygen transport. Taking iron supplements in the morning can optimize absorption and prevent interference with other nutrients
  • Probiotics: Probiotic supplements contain beneficial bacteria that support gut health and digestion. Taking them in the morning can help populate the gut with beneficial bacteria and support digestive function throughout the day
  • Omega-3 fatty acids: Omega-3 supplements, such as fish oil, are known for their anti-inflammatory properties and support for heart and brain health. Taking them in the morning can provide a daily dose of these essential fatty acids


Multivitamins are supplements that contain a combination of essential vitamins and minerals to support overall health and fill nutritional gaps. When taking supplements, it's important to be cautious about potential interactions and consult with a healthcare professional. Mega-dosing and combining supplements improperly can lead to toxicity and adverse effects. The number of supplements to take depends on individual needs, and it's best to obtain nutrients from a balanced diet. Some supplements are recommended to take at night, such as magnesium and melatonin for better sleep, while others like B vitamins and probiotics are beneficial in the morning for energy and digestion support.


  1. Vancouver StyleResearch VM. GlobeNewswire News Room. 2023 [cited 2023 Jul 2]. Protein supplements market size & share to surpass $20. 2 billion by 2028 | vantage market research. Available from: https://www.globenewswire.com/en/news-release/2023/02/07/2602628/0/en/Protein-Supplements-Market-Size-Share-to-Surpass-20-2-Billion-by-2028-Vantage-Market-Research.html
  2. Search results for ‘testosterone and winstrol side effects’ - Max Steroids [Internet]. [cited 2023 Jul 2]. Available from: https://max-steroids.com/search/?search=testosterone+and+winstrol+side+effects
  3. Mount Sinai Health System [Internet]. [cited 2023 Jul 2]. Multiple vitamin overdose information | mount sinai - new york. Available from: https://www.mountsinai.org/health-library/poison/multiple-vitamin-overdose
  4. Nao D. Is melatonin safe for insomnia patients? Here’s what you need to know [Internet]. Nao Medical. 2023 [cited 2023 Jul 2]. Available from: https://naomedical.com/blog/is-melatonin-safe-for-insomnia-patients/
This content is purely informational and isn’t medical guidance. It shouldn’t replace professional medical counsel. Always consult your physician regarding treatment risks and benefits. See our editorial standards for more details.

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Dr. Soha Farooq

Doctor of Pharmacy- Pharm.D, Shifa Tameer e Millat University, Pakistan

Dr. Soha Farooq is a remarkable pharmacist, captivating medical health writer, and dedicated philanthropist.

With an unwavering commitment to improving health literacy, Dr. Soha strives to inspire, educate, and empower individuals to take control of their well-being. Her words have the power to spark change, foster understanding, and create a positive impact on the lives of her readers.

In her pursuit of excellence as a pharmacist, writer, photographer and a philanthropist, Dr. Soha embodies the true essence of a multi-talented professional who uses her skills and passions to make a meaningful difference in the world of healthcare and beyond.

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