Interaction checker

Vitamin C (ascorbic acid) enhances absorption of non-heme iron (plant-based iron) by reducing ferric iron to ferrous form and chelating iron at acidic pH, significantly increasing bioavailability. This synergistic effect is particularly important for vegetarians/vegans relying on plant-based iron sources, with vitamin C increasing non-heme iron absorption by up to 3-4 fold when consumed together.

1 study

Magnesium affects vitamin D absorption, which influences psoriasis pathogenesis.

3 studies

Low serum glycine strengthens the positive association between branched-chain amino acids and impaired insulin sensitivity markers (HOMA2-IR).

1 study

Fiber acts as a prebiotic substrate that selectively feeds beneficial probiotic bacteria, enhancing their survival, colonization, and metabolic activity in the colon. This synergistic relationship improves the overall efficacy of probiotics by providing the necessary carbohydrate source for probiotic proliferation and the production of short-chain fatty acids.

2 studies

Ashwagandha and magnesium work synergistically to support stress reduction and sleep quality through complementary mechanisms—ashwagandha modulates cortisol and GABA signaling while magnesium supports GABA receptor function and reduces neuromuscular tension. Combined use may enhance relaxation and sleep initiation without direct pharmacokinetic interactions or contraindications.

Vitamin D combined with docosahexaenoic acid (DHA) shows the strongest effect in reducing triglycerides in pediatric patients with metabolic dysfunction-associated steatotic liver disease.

2 studies

Vitamin B6 (pyridoxine) enhances magnesium cellular uptake and utilization by facilitating magnesium-dependent enzyme reactions and improving intracellular magnesium transport. This complementary relationship supports magnesium bioavailability and downstream metabolic functions that require both cofactors, particularly in energy metabolism and neuromuscular regulation.

Magnesium and melatonin work through complementary mechanisms to support sleep: magnesium activates GABA receptors and reduces nervous system excitability, while melatonin regulates circadian rhythm signaling. Combined use may enhance sleep onset and quality, as magnesium deficiency can impair melatonin receptor sensitivity and reduce overall sleep efficacy.

Vitamin K2 activates osteocalcin and matrix Gla protein (MGP), which are carboxylated K2-dependent proteins that bind and direct calcium into bone matrix while inhibiting vascular calcification. Adequate calcium intake is necessary for K2 to exert this bone-directing effect, making concurrent intake mutually beneficial for optimal skeletal mineralization and cardiovascular health.

1 study

Curcumin and omega-3 fatty acids both inhibit pro-inflammatory pathways (NF-κB, COX-2, and production of inflammatory cytokines), with complementary mechanisms that may produce additive anti-inflammatory effects. Combined use has shown promise in small studies for conditions like rheumatoid arthritis and cardiovascular disease, though large-scale RCTs specifically evaluating the combination are limited.

5 studies

Adding vitamin C to vitamin E does not change the effect on normalizing serum ALT in pediatric nonalcoholic fatty liver disease.

9 studies

Magnesium is an essential cofactor for the enzymatic activation of vitamin D, converting inactive 25-hydroxyvitamin D to the active 1,25-dihydroxyvitamin D form in the kidneys. Adequate magnesium status is required for optimal vitamin D metabolism and biological function, meaning magnesium deficiency can impair vitamin D activation regardless of vitamin D intake.

CoQ10 and Omega-3 fatty acids work synergistically to support cardiovascular health through complementary mechanisms: Omega-3s reduce triglycerides and inflammation while improving endothelial function, while CoQ10 enhances mitochondrial energy production in cardiac cells and provides antioxidant protection. Combined supplementation may offer additive benefits for blood pressure regulation, arterial compliance, and heart function.

NAC (N-acetylcysteine) and vitamin C work synergistically to support glutathione metabolism through complementary pathways: NAC provides cysteine as a rate-limiting precursor for glutathione synthesis, while vitamin C acts as a cofactor and antioxidant that helps recycle oxidized glutathione (GSSG) back to its reduced form (GSH). This combination enhances intracellular antioxidant capacity and cellular redox balance more effectively than either agent alone.

Vitamin A and vitamin D together interact to affect backfat thickness and USDA Yield grade in feedlot cattle.

5 studies

Selenium and myo-inositol have a synergistic effect on thyroid function when used simultaneously in patients with thyroid disorders.

2 studies

No significant association between dietary folate intake and breast cancer risk was observed when stratified by vitamin B12 consumption.

21 studies

Vitamin D fortification enhances the effect of iron fortification on erythropoiesis.

3 studies

DHA supplementation increases serum insulin levels more than EPA supplementation.

2 studies

Addition of fiber (30g/day) to MCT supplementation did not interfere with MCT efficacy in improving quality of life and pain outcomes in rheumatoid arthritis patients.

1 study

The association between low plasma PLP and increased acute myocardial infarction risk is stronger in patients with high serum vitamin A compared to low serum vitamin A.

1 study

Vitamin D combined with docosahexaenoic acid (DHA) showed the strongest effect in reducing triglycerides in pediatric MASLD.

4 studies

The combined efficacy of caffeine and taurine remains inconclusive.

2 studies

Melatonin combined with myoinositol plus folic acid increased the number of MII oocytes compared to myoinositol plus folic acid alone.

1 study

Omega-3 and prebiotic fibre (inulin) may have synergistic anti-inflammatory effects when combined as a synbiotic intervention.

1 study

Synbiotic supplementation (probiotics + omega-3 combined) produces superior effects on high-velocity upper-body strength compared to probiotic or omega-3 supplementation alone.

1 study

Folic acid combined with other B vitamins is more effective for reducing homocysteine levels than folic acid alone in healthy adults.

3 studies

The effect of lipid-based nutrient supplements on cobalamin (vitamin B12) status was reduced in children with low plasma citrulline (<20 µmol/L), showing 20% lower increase in plasma cobalamin.

1 study

Milk protein concentrates, collagen peptides, and whey protein hydrolysates exhibited synergistic effects on zebrafish bone development.

1 study

Caffeine and Rhodiola rosea supplementation together may have synergistic effects on fatigue recovery in male volleyball players.

2 studies

Vitamin B supplementation showed positive effects on cognitive outcomes in non-aspirin users with high omega-3 fatty acid plasma levels.

6 studies

Combined vitamin D and synbiotics supplementation resulted in a notable increase in the anti-inflammatory index, suggesting potential synergistic anti-inflammatory effects in breast cancer patients.

2 studies

Vitamin A and vitamin E were co-administered in two of the included studies for acute upper respiratory tract infection prevention.

3 studies

Combined magnesium and potassium supplementation may act synergistically to regulate insulin resistance and blood sugar levels more effectively than placebo in insomniac diabetics.

1 study

Chromium is more effective than omega-3 in improving insulin resistance index (HOMA-IR) in PCOS patients.

1 study

Co-supplementation with whey protein and vitamin D significantly enhanced lean mass gains with a standardized mean difference of 0.993.

2 studies

Combined oral contraception and antioxidant supplementation did not reduce HOMA-IR more than oral contraception alone in women with PCOS.

1 study

Exercise training combined with probiotics is more efficient than exercise training alone in reducing ALT levels in patients with NAFLD.

1 study

Vitamin D and vitamin E supplementation alone or in combination with other interventions appear beneficial in specific patient groups with pediatric NAFLD.

1 study

Within citrulline-supplemented participants, those with low protein intake had greater reductions in gynoid fat mass than those with high protein intake.

1 study

Co-supplementation of β-alanine with sodium bicarbonate produced the largest effect size (0.43) compared to placebo, suggesting synergy.

2 studies

Combining curcumin with piperine produced a greater MDA-lowering effect than curcuminoids alone.

6 studies

The combination of nocturnal melatonin and next-day caffeine reduced markers of muscle damage (CK, LDH, AST, ALT) after high-intensity exercise compared with placebo, melatonin alone, and caffeine alone.

1 study

Co-supplementation with vitamin C blunted the acute increase in urinary N-nitroso compound excretion after a single beetroot juice dose but not after 7 consecutive days.

1 study

Combining vitamin C with dietary nitrate may synergistically support NO bioavailability and vascular function compared to nitrate alone.

1 study

Simultaneous consumption of probiotics and casein produced a more pronounced effect on aerobic capacity indicators than either supplement alone, suggesting a synergistic interaction.

1 study

Co-ingesting caffeine with sodium bicarbonate produces additive/synergistic effects on pacing, anaerobic contribution, and respiratory parameters beyond NaHCO3 alone during high-intensity cycling.

1 study

There was no significant interaction between sodium bicarbonate and acetylcysteine with respect to the primary composite renal/mortality endpoint (P=0.33).

2 studies

Curcumin addition to vitamin D supplementation had no additional effects on disease activity or inflammatory markers in SLE patients.

1 study

Increased folate intake was positively associated with changes in choline concentration in the 2RDA protein diet group.

1 study

Combined choline and DHA supplementation prevented the decrease in DHA in phosphatidylcholine relative to total lipid that occurred with DHA alone.

1 study

Resveratrol supplementation showed greater bone-protective benefit in postmenopausal women who also supplemented with vitamin D3 and calcium.

1 study

The combination of heat-killed Levilactobacillus brevis KB290 and β-carotene showed a synergistic effect in reducing influenza infection risk in younger adults.

1 study

Bifidobacterium has the potential to enhance the hypoglycemic effect of berberine when used in combination.

1 study

BHC add-on therapy showed a synergistic interaction with metformin, producing greater glucose control improvements than metformin monotherapy alone.

1 study

Acute administration of bioavailable curcumin (HydroCurc™ 500 mg) alongside ferrous sulphate does not impair iron absorption in healthy adults.

1 study

The effect of creatine supplementation on arsenic methylation capacity is modified by choline nutritional status, with greater effects observed in individuals with low choline status.

1 study

The efficacy of folic acid treatment on cognitive functioning is dependent on baseline omega-3 fatty acid status, with lower omega-3 status being associated with greater benefit.

2 studies

Combined melatonin, tryptophan, and vitamin B6 has a stronger influence on reducing night awakenings in children compared to melatonin alone.

1 study

Zinc supplementation had an effect on salivary IgA among younger children after vitamin A supplementation.

2 studies

Selenium presence in antioxidant mixtures modulates the cardiovascular and mortality benefits, showing beneficial effects when included and harmful effects when absent.

9 studies

Combined folic acid (400 μg) and creatine (3 g) supplementation showed no additional benefit over folic acid alone in altering arsenic metabolite proportions.

1 study

The effect of β-carotene supplementation on mortality was modified by dietary vitamin C intake and fruit/vegetable intake.

1 study

CFH genotype did not significantly modify the response to AREDS2 nutrient supplements with respect to progression to late AMD, geographic atrophy, or neovascular AMD.

1 study

Magnesium and vitamin E co-supplementation had a synergistic beneficial effect on insulin metabolism and cardio-metabolic risk markers in women with PCOS.

1 study

Magnesium and zinc demonstrate a synergistic co-supplementation effect, with combined administration producing beneficial anti-inflammatory and antioxidant effects in PCOS.

1 study

Creatine uptake is increased in the presence of electrolytes, suggesting a synergistic interaction between creatine and electrolytes.

1 study

Significant interaction was found between treatment arms and immune status category on time to development of nosocomial infection and sepsis.

1 study

Trans-resveratrol plus D-chiro-inositol and myo-inositol (group I) produced significantly greater improvements in glucose and lipid parameters than D-chiro-inositol and myo-inositol alone (group II) at 30 to 60 days.

1 study

B vitamin treatment (vitamin B6 and folic acid/B12 combined) increases the risk association between MTHFD1 polymorphism and myocardial infarction.

2 studies

Plasma coenzyme Q10 levels were significantly positively correlated with vitamin E levels after supplementation in hepatocellular carcinoma patients after surgery.

2 studies

Selenium and CoQ10 supplementation demonstrated a synergistic cardioprotective effect independent of baseline oxidative stress biomarker levels.

1 study

Combining capsaicin with elevated dietary protein produced greater fat oxidation (lower RQ) than capsaicin alone during negative energy balance.

1 study

Combined vitamin A and iron supplementation increased total body iron content (BTIC) to the same degree as iron supplementation alone.

2 studies

A synergistic interaction exists between fish oil and vitamin C on sperm motility and progressive motility percentage.

2 studies

Synergistic effect observed: multivitamins combined with selenium was effective, whereas multivitamins alone and selenium alone showed no significant benefit.

2 studies

Co-administration of methyl donors (betaine HCl 1.6 g/day, vitamin B12 5 μg/day, vitamin B6 10 mg/day, folic acid 600 μg/day) with guanidinoacetic acid (2.4 g/day) prevents hyperhomocysteinaemia in healthy volunteers.

1 study

Fish oil supplementation may interact with antioxidants (selenium and vitamin C) and inflammatory response to impact physical performance.

1 study

Orthosiphon stamineus addition to the nutraceutical combination demonstrates a synergistic antihypertensive effect in patients with grade 1 hypertension.

1 study

Vitamin D and Vitamin K2 work synergistically to regulate calcium metabolism and bone mineralization through complementary mechanisms: Vitamin D enhances intestinal calcium absorption and activates osteocalcin (a bone matrix protein), while Vitamin K2 carboxylates osteocalcin, enabling it to bind calcium and direct mineral deposition to bone rather than soft tissues. This coordinated action reduces cardiovascular calcification risk while optimizing skeletal mineralization.

4 studies

Vitamin E functions as a lipophilic antioxidant that protects polyunsaturated omega-3 fatty acids from oxidative degradation, preserving their bioavailability and efficacy. This complementary mechanism allows omega-3 supplements to maintain their structural integrity and therapeutic potency, particularly important given omega-3's inherent susceptibility to lipid peroxidation.

4 studies

L-theanine and caffeine work synergistically through complementary mechanisms: caffeine increases alertness via adenosine receptor antagonism, while L-theanine promotes alpha brain wave activity and enhances GABA/dopamine signaling, thereby attenuating caffeine-induced jitters and anxiety without reducing its stimulant benefits. Multiple studies demonstrate that this combination improves attention and task performance more effectively than either agent alone, with reduced sympathomimetic side effects.

9 studies

Vitamin D enhances intestinal calcium absorption by upregulating calcium-binding proteins and increasing active transcellular transport in the small intestine, particularly in the duodenum and jejunum. This synergistic relationship is well-established and forms the physiological basis for combined supplementation in osteoporosis prevention and treatment.

35 studies

Both magnesium and calcium compete for absorption in the intestines through similar pathways, with high doses of one reducing bioavailability of the other. However, they are both essential minerals that work synergistically in bone health and numerous physiological processes, so the primary concern is optimizing absorption rather than avoiding concurrent use.

The calcium-to-magnesium intake ratio affects magnesium absorption and should be considered in future studies.

1 study