Common Supplements and their interaction with Medicines


The wellness market is flooded with herbal supplements, multi-vitamin tablets, antioxidant drinks and various other fancy supplements! It is marketed as if, if one needs to become healthy then they cannot do so without these pills and powders. These supplements are very often marketed as magic pills and panacea for health problems. On the contrary, many of these supplements end up causing health issues, and liver & kidney diseases due to unscrupulous usage!

Many of these supplements often interact with other medicines – some minor to moderate interactions, while some can be acute interactions and highly dangerous.

Common Supplements & Herbs Interactions

Calcium Supplements

Do not mix calcium supplements with heart medications such as digoxin, as it can increase the effect of medicine greatly. Calcium supplements should also be avoided along anti-hypertensives, especially calcium channel blockers and diuretics.

Calcium supplement is also seen to interact with quinolone and tetracycline antibiotics and certain osteoporosis drugs like bisphosphonates reducing its effectiveness

Omega – 3 (Fish oil)

Omega 3 supplements are best avoided along with anti hypertensive (BP tablets) and anti-coagulants, as they can increase the effect of these medications. It also interacts with cancer medications and reduces it effect.

CoQ10 (Coenzyme Q10)

CoQ10 should be avoided along with blood thinners and cancer medications as it reduces its effectiveness. It is also not suggested along with BP medications, as it increases the effect of anti-hypertensives


Ashwagandha, also popularly known as ‘Indian ginseng’ is used as an ingredient in many ayurvedic formulations. It has become a popular supplement, especially among the gym-going crown due to its purported benefits of increasing testosterone and muscle hypertrophy (muscle gain). The research studies around these claims are still inconclusive and debated, but the supplement has fast become very popular.

Aswagandha can interfere with thyroid medicines, BP and diabetes medications. It brings down blood glucose and can cause hypoglycemia if consumed along with diabetic medications. Aswagandha if taken along with antihypertensive medications may lower blood pressure dramatically (especially ACE Inhibitors and Calcium channel blockers. Note – ACE inhibitors end with ‘pril’, calcium channel blockers end with ‘dipine’).

It may also stimulate immune response and is hence best avoided for those with auto-immune diseases like lupus, rheumatoid arthritis and Hashimoto’s thyroiditis. Those on treatment with cyclophosphamide for cancer, lupus, ovarian and breast cancer should completely avoid ashwagandha as it can reduce its effectiveness. Aswagandha should also be avoided with immuno-supressant medications such as cyclosporine, mycophenolate, tacrolimus, prednisone and other corticosteroids.


Garlic is considered to be healthy for the heart for its purported benefits in reducing bad cholesterol (LDL) and triglycerides. Some studies even point to garlic being helpful to manage blood pressure, as it acts like a vasodilator (i.e increases the diameter of blood vessels, thereby reducing the pressure). Garlic added to the food is not known to create any major drug interaction. But, garlic is also added to many herbal concoctions and supplements and is also available as powder and supplement-pills

Garlic can interact with certain immunosuppressant medications like cyclosporine making them less effective. It also reduces the effectiveness of drugs like Isoniazid that are used for the treatment of TB (Tuberculosis). It also reduces the effectiveness of birth control pills and HIV drugs

On the other hand, it interacts with blood thinners such as heparin, warfarin (Coumadin), fluindione, aspirin etc, making them stronger and increasing the risk of bleeding. It can also increase the effect of medicines like clopidogrel (Plavix). Avoid garlic supplements along with antihypertensive medications. Since garlic has a vasodilator like an effect on the blood vessels, taking them along with anti-hypertensive medications can make the blood pressure go very low


Ginger has properties that may help reduce nausea and swelling. It is also used to reduce menstrual cramps, and morning sickness during pregnancy and may also help to control blood sugar in diabetic patients.

Ginger taken in small quantities in food is not known to cause any major side effects or drug interactions. However, ginger in the form or supplements, or in large quantities added to concoctions can interact with many prescription drugs. Ginger also increases the effectiveness of anticoagulant drugs. Consuming large quantities of ginger along with such drugs (warfarin, heparin, aspirin) can hence increase the risk of internal bleeding.

Ginger should be avoided with anti-hypertensive medications (BP medicines). Ginger is known to reduce blood pressure through the blockage of voltage-dependent calcium channels. Hence consuming ginger supplements along with BP medicines – especially, calcium channel blockers such as Amlodipine, and Nifedipine can potentially bring down BP to dangerously low levels. Ginger also increases the effect of many other types of BP medications and is hence best avoided along with them. Ginger also increases the effectiveness of antibiotic drugs like Metronidazole and should be avoided consuming together.

Ginger is also best avoided with immunosuppressant medicines like cyclosporine as it increases side effects.


Ginseng reduces the effect of blood thinners, while it increases the effect of antihypertensive medications and diabetic medications. It also interacts with steroid medicines, NSAIDs, anti depressants and digoxin.


Ginkgo may interact with anticoagulants like warfarin, aspirin, and increase its effect increasing the chances of internal bleeding. It also interacts with NSAID medicines (non-steroid anti inflammatory drug). It is also known to reduce the effectiveness of anticonvulsant drugs (treats seizure) and antidepressants (serotonin reuptake inhibitors). It also reduces the impact of medicines to treat anxiety.


DHEA (Dehydroepiandrosterone) supplements consumed along with anticoagulants like warfarin, heparin, aspirin and ecospirin will increase its effect and can cause internal bleeding. DHEA is also unsafe to consume along with antidepressant medicines. DHEA may reduce the impact of anti-estrogenic cancer drugs such as tamoxifen, aromatase inhibitors (anastrozole), and fulvestrant. DHEA may increase the impact of medications used for insomnia, such as triazolam/benzodiazepine. It can also decrease the effectiveness of the BCG vaccination for tuberculosis.

DHEA supplements are also not suggested to be consumed along with anti-depressants

Green Tea Extract

Green tea leaves are very high in vitamin K which helps in blood clotting. Green tea extract should hence not be combined with blood thinner medications (warfarin, heparin, aspirin). Green tea should not be combined with a specific class of drugs called Amphetamines which are central nervous system stimulants. Caffeine in green tea along with such psychostimulant drugs may exacerbate the side effects.

Green tea extract should be avoided with drugs used for the treatment of Parkinson’s and depression (particularly Monoamine oxidase inhibitor drugs). Green tea also reduces the absorption of the cholesterol medication, atorvastatin. It also reduces the levels of a type of blood pressure medicine called Nadolol in the blood plasma

Also Read: Will green tea help in weight loss?

Milk Thistle

Silymarin, the active ingredient of the milk thistle plant is an antioxidant and is sold as a supplement. This is claimed to be hepato-protective and reduce liver inflammation. Milk thistle can interfere with diabetic drugs and bring down blood glucose more than anticipated. It also interferes with blood thinners like warfarin and can cause internal bleeding. It also interacts with diazepam, a drug used to treat alcohol withdrawal, anxiety, seizures and muscle spasms.

It also interferes with Raloxifene, a drug that is used to treat osteoporosis, especially among women after menopause. Milk thistle also interferes with Simeprevir, hepatitis – C medication. Milk thistle should also be avoided along with immuno-suppressant medications.


Melatonin may increase the effects of anticoagulants such as warfarin causing bleeding. It may increase the effects of medicines like benzodiazepines used to treat seizure, depression and anxiety, causing more sedation. Melatonin supplements should be avoided with anti-depressants like fluvoxamine & desipramine, estrogen medications, and quinolone antibiotics as it increases its effect. It should also be avoided with antiseizure drugs such as carbamazepine and antipsychotic medications

Melatonin can also interact with anti-hypertensive – especially calcium channel blockers and beta blockers.

St John’s Wort

St John’s wort interacts with a number of medications. It reduces the effectiveness of allergy drugs, anti anxiety medications, anticonvulsants, antihypertensives (calcium-channel blockers), birth control pills, cholesterol lowering medicines (statins), hear medications like digoxin, PPIs(acidity/GERD) and immunosuppressants

It also interacts with blood thinners, migrane medications and anti-depressants.


Valerian increases the effect of anti anxiety drugs and anti-depressants

Magnesium Supplements

Magnesium supplements can reduce the absorption of antibiotics and reduce their impact. Magnesium is also best avoided along with BP medications – especially, calcium channel blockers. It also interacts with certain diabetic medications and increases their impact causing very low blood sugar levels (drugs that fall under the sulfonylurea class – glipizide, glyburide etc)

Magnesium also interferes with medications for certain bone diseases and osteoarthritis such as Tiludronate and Alendronatek. Keep at least a 6-hour gap between the supplement and medicine and check with your doctor.

Diuretics (for reducing bloating, reducing BP etc) can reduce the levels of magnesium in the body. Digoxin, a popular drug used for the treatment of heart conditions also depletes magnesium levels in the body. Always talk to your doctor and understand the required dosage of magnesium and duration required, before supplementing with magnesium in such cases

Vitamin C Supplements

Vitamin C reduces the impact of blood thinners like warfarin and should be avoided together. It also reduces the effectiveness of cancer and chemotherapy medications. High levels of vit-C can increase the amount of paracetamol (acetaminophen) in the blood and is hence suggested to be avoided consuming together.

Vit C also interacts with estrogen tablets like estradiol that are prescribed for hormone replacement therapy for women during menopause and also for PCOS

Also Read: Vit-C Sources (Other than lemon & orange)

Vitamin D Supplements

Vitamin D supplements if taken along with antihypertensive such as calcium channel blockers can reduce the effectiveness of the drug. It also reduces the effect of cholesterol-lowering statin medications such as rosuvastatin, and atorvastatin. It may also cause side effects along with diuretics or water pills.

Also Read: Vit D Source

Vitamin E Supplements

Vitamin E should be avoided along with cancer medication as it reduces its effectiveness. On the other hand, Vit-E increases the impact of anticoagulants (blood thinners such as warfarin) and hence should be avoided consuming together. Vit-E also increases the side effects associated with immunosuppressant drugs such as cyclosporine

Vit-E also interferes with antidepressant medications (tricyclics like desipramine, imipramine and nortriptyline). It also interferes with medications for schizophrenia, bipolar disorder, and acute psychosis.

It also interferes with beta-blockers which are a class of antihypertensive medications to treat BP (eg – propranolol, atenolol and metoprolol.) Note:- beta-blocker tablets end with ‘lol’ at the end.

Cholesterol-lowering drugs (bile-acid sequestrants like colestipol & cholestyramine and fibric acid derivatives like Gemfibrozil) can reduce the absorption of Vitamin E. On the other hand, cholesterol-lowering statins reduce the anti-oxidant potential of Vitamin E. Anthelmintic medications like Albendazole & Mebendazole, to treat parasitic worms and tapeworm are seen to be less effective when taken with Vitamin E

Also Read: The Antioxidant Vitamin – Vit E

Biotin (Vit B7)

Biotin supplements are usually consumed for reducing hair fall and improving hair health. Biotin supplements are not known to interact majorly with any medications. However, they can interact with thyroid assays; it is hence recommended to stop the biotin supplementation for at least 3 days before taking a thyroid function test – else, the test values will be inaccurate. Biotin can make the thyroid function test results wrong with falsely high levels of T4 and T3 and falsely low levels of TSH. This could lead to the medical practitioner wrongly diagnosing hyperthyroidism or wrongly reducing your thyroid hormone replacement dose (Thyronorm tablet) if you have hypothyroidism.

Long-term antibiotics usage can kill the bacteria in the gut that synthesised biotin. Similarly, certain medicines called anticonvulsants that are used for the treatment of seizures, and epilepsy can also deplete the biotin stores. Some examples of anticonvulsant drugs are – Valproic acid, Carbamazepine/Tegretol, Phenobarbital/Luminal, phenytoin/Dilantin and Primidone

Always speak to your doctor before consuming a biotin supplement in such cases

Vitamin B12

Vitamin b12 or Cobalamin is generally deficient in people who are pure vegetarians. Long-term use of antibiotics also reduces the vit B12 levels in our body. Vitamin B2, B7 (Biotin) B9, B12 are more prone to be depleted as they are produced by the bacteria in our gut. Vit b12 also goes deficient with drugs like metformin (diabetic drug) and Bile acid sequestrants to treat cholesterol. Both PPI (pantoprazole, rabeprazole etc) and H2 blockers (ranitidine) used to treat acidity/GERD also can reduce the Vit B12 levels in our body

Vit B12 interferes with a class of drugs called tetracyclines used to treat pneumonia, cholera, malaria and syphilis and should hence be avoided together


BCAA supplements can potentially interact with diabetic medications and are hence best avoided around the same time. Stop consuming BCAA at least 2 weeks before any scheduled surgery.

BCAA also interferes with levodopa, a drug used to treat Parkinson’s disease

Creatine Monohydrate

Creatine is one of the most-studied and researched supplements. It is a safe supplement with immense health benefits. However, people with kidney and liver issues should avoid this supplement.

Taking Creatine along with NSAIDs like ibuprofen, and naproxen can cause kidney damage. Creatine and caffeine should not be taken together, as it can cause dehydration and in severe cases even stroke. Creatine also interacts with certain types of drugs such as – anti-histamines like cimetidine, antiviral medications like entecavir (Hepatitis B), chemotherapy medicines like Pemetrexed, gout medications like Probenecid and antibiotics like Trimethoprim

Stop creatine supplementation at least 3-4 days before taking an RFT (Kidney/Renal function test), as it can give false values in the test.


Collagen is a structural protein that our body produces; it is the basic structural element of skin, bone and nails. Collagen supplements are consumed to improve skin health, and also for joint pains related to osteoarthritis. Collagen when consumed as a supplement, it acts similarly to a protein. There are currently no known interactions with any medications. However, it will be prudent to not consume this with any prescription drugs.

Also, note that most collagen supplements come along with other components such as glucosamine, vitamin C etc which are known to interact with medicines.


Glucosamine can interact with blood thinners like heparin and warfarin and should be avoided together. Glucosamine also interacts with ibuprofen and increases its NSAID properties.


Chondroitin supplements almost always come with glucosamine. Chondroitin is similar to heparin, a medicine used as a blood thinner, in terms of its chemical structure. Chondroitin is hence purported to increase the effectiveness of such medications, including heparin (yet another anti-coagulant drug). It is best to avoid glucosamine with antiplatelet agents like aspirin and clopidogrel

Garcinia Cambogia

Garcinia Cambogia should be avoided along with anti depressant and physchotic drugs as it can increase the levels of serotonin in the brain

Things to remember

For a common man who is not into medical field, it is difficult to comprehend or remember the drug names, their classification/types and corresponding interactions with different type of supplements. It will be prudent to not consume any supplements with prescription as a blanket approach to avoid any sort of interactions. Also do not mix up medications of different types (ayurveda, homeopathy, allopathy etc)

  1. DO NOT consume supplements and herbal concoctions unscrupulously. In almost all cases, supplements are not meant to be consumed for long periods of time
  2. All that is natural and organic need not always be good for our health
  3. Avoid mixing up different types of medications at the same time (Ayurveda, Homeopathy, Allopathy)
  4. Always ask a medical practitioner and understand the side effects and drug interactions before consuming any supplement.
  5. Many of the drugs mentioned here may be known by their brand name. Only a medical practitioner may know the constituents of the medicines you are prescribed and hence the interaction with other dietary supplements
  6. Most of the drug-supplement interactions are with blood thinners, anti-hypertensives, anti-depressant and anti-psychotic medications. Avoid consuming any supplements along with the medicines in these categories
  7. Certain medications are always best consumed in empty stomach without any other drug, or nutrients along with it. Example – Thyroid (hypo) medications like thyronorm, Eltroxin, levothyroxine
  8. If possible, keep a gap of alteast 8 – 10 hours between the dietary supplements and medications
  9. As a general practice, if you are on any prescription medications for a short time period to treat any specific health conditions such as common cold, infections, inflammation etc, stay away from all supplements or herbs during the course (period) of medication
  10. There are no magic pills or magic supplements. NOTHING can be a replacement for a healthy lifestyle change that involves balanced nutrition and exercise

About NuvoVivo

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This Post Has 3 Comments

  1. Shishir

    Is it safe to consume Whey Protein Supplements?

    1. [email protected]

      Absolutely! whey protein is one of the most bio-available protein. it is safe to be consumed as long as the total protein intake in a day is within the required limits (1 to 1.5 grams per kg of body weight for a normal individual with moderate to regular exercises/activity). That said, avoid whey if the kidney health is impaired (high creatinine, protein in urine), or if the uric acid levels are high

  2. Saddie

    Vitamin D has been on my radar for bone health, but realizing it can affect the effectiveness of my BP meds is crucial. As a retiree enjoying family time, health is a priority. This article reminds me to stay informed and adjust my supplement routine for a healthier retirement! On a related note, I’ve incorporated a Vitamin supplement into my daily routine, and it seems to be helping me maintain my energy levels and overall well-being.

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