Major interaction on record — check this product against your medications before combining. Based on 3 of 5 ingredients. Check your meds →
Dietary supplement

Factor 2 Pre-Workout Ingredients & Drug Interactions

by Force Factor

Factor 2 Pre-Workout label
See full label image
Capsule Category: Botanical With Nutrients
Most serious interaction: Major
Clinical methodology reviewed by · Updated Sep 16, 2026 · Label data from the NIH DSLD
What is this page for?

First and foremost: checking Factor 2 Pre-Workout against your medications. The heart of this page is the interaction checker and the full interaction report — how this product’s ingredients may interact with prescription and over-the-counter medicines you may be taking.

Around that, we add a pharmacist’s high-level view of the product as a whole — what’s inside, the evidence for its stated use, how transparent the label is, and what safety data exists — so you can see the full picture in one place. It’s educational information from our licensed clinical databases and the clinical staff at HelloPharmacist — not medical advice — and we don’t sell or endorse products. Our editorial policy

The interaction bottom line Most serious interaction: Major

Factor 2 Pre-Workout is a dietary supplement by Force Factor with 5 active ingredients. Its ingredients are commonly taken for preventing neural tube birth defects, treating or preventing folate deficiency, supporting pregnancy health.Based on those ingredients, 394 medications have a known interaction with it, the most serious rated major. The ingredients most likely to interact are Vitamin C, Calcium, Folic Acid. Use the checker below to test your specific medication, or read the full HelloPharmacist Interaction Report.

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Check Your Meds Against Factor 2 Pre-Workout by Force Factor

Ask about any prescription or over-the-counter medication and we check it for interactions with Factor 2 Pre-Workout by Force Factor — and tell you which ingredient is responsible.

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HelloPharmacist Scorecard of Factor 2 Pre-Workout by Force Factor

Our pharmacy team’s full take, with four database checks built into the cards below — a summary of what is known, not a grade of the product itself.

From our pharmacy team — supplement deep dive

Generated from HelloPharmacist’s pharmacist-curated databases and editorial rules · Last generated Jul 30, 2026

What’s inside

Partial disclosure
Ingredient Transparency · database check
Partial

Most active ingredients list an amount, but at least one is hidden in a blend or missing.

Why this rating?
  • The label discloses an exact amount for 3 of its 5 active ingredients.
  • “Dual Stage Next-Gen NOXplosion” is listed as a grouped ingredient — the label gives one combined amount (1,285 mg) without saying how much of each component you get.

Factor 2 Pre-Workout contains five active ingredients. Three are straightforward: folic acid (a B vitamin), calcium (a mineral), and vitamin C (ascorbic acid for antioxidant and other functions).

The other two — Dual Stage Next-Gen NOXplosion blend, Stage 1-Substrate Input Regeneration Complex, and Stage 2-Dynamic NOx Enzyme Catalysis System — are proprietary blend components; the product doesn't break down their individual contents, so we can't fully assess their interactions. The capsule also contains inactive ingredients (cellulose, magnesium stearate, gelatin, and food dyes) that serve as fillers and binders.

Does it work?

Insufficient evidence
Evidence for Intended Use · database check
By FDA rules, dietary supplements can’t claim to treat, cure, or prevent disease — so labels speak in careful marketing language. We discern each product’s intended use from its name, label claims, and label statements, then grade the clinical evidence for that use. How these ratings are computed
Insufficient

There isn't enough reliable clinical evidence to rate this product's ingredients for its stated purpose.

Why this rating?
  • The label markets this product for: nitric oxide booster for muscle building strength.
  • We looked for evidence on: Athletic performance, Exercise-induced muscle damage, Erectile dysfunction (ED), muscle hypertrophy, vascular function, endothelial health.
  • The closest evidence on file: Calcium is rated "Insufficient Reliable Evidence To Rate" for Exercise-induced muscle damage (Natural Medicines).
  • Also on file: Vitamin C is rated "Insufficient Reliable Evidence To Rate" for Athletic performance, Exercise-induced muscle damage.
  • Also on file: Folic Acid is rated "Insufficient Reliable Evidence To Rate" for Erectile dysfunction (ED).

The evidence for these ingredients is mixed. Folic acid is effective for treating folate deficiency and likely effective for preventing neural tube birth defects and reducing methotrexate toxicity; it's possibly effective for depression and cognitive impairment.

Calcium is effective for kidney failure, indigestion, and low blood calcium (hypocalcemia), and likely effective for osteoporosis. Vitamin C is effective for vitamin C deficiency and possibly effective for anemia of chronic disease, atrial fibrillation, cataracts, and preventing respiratory infections triggered by exercise.

We have no effectiveness data on file for the proprietary blend components Stage 1 and Stage 2, since their identities aren't disclosed.

The evidence, ingredient by ingredient Folic Acid Calcium Vitamin C

How safe is it?

Well-documented data
Safety Information · database check
Well characterized

Adverse-effect, pregnancy, and general safety data are on file for most of these ingredients.

Why this rating?
  • We hold adverse-effect (side-effect) data for 3 of the 3 matched ingredients.
  • Pregnancy & breastfeeding safety ratings cover 3 of 3.
  • General safety write-ups exist for 3 of 3.
  • Remember: this measures how much safety information exists. Thin data is not the same as being safe.

Folic acid and calcium are generally safe at recommended doses for most adults. Folic acid is recommended during pregnancy at standard prenatal doses to help prevent birth defects and is considered safe while breastfeeding at normal amounts.

Calcium is important in pregnancy and safe when taken within recommended amounts; it's safe during breastfeeding when needs are met from recommended amounts. Vitamin C is generally well-tolerated at normal dietary and supplement doses, but the safety notes advise caution with high-dose supplements during pregnancy and breastfeeding — stick to normal amounts from food and prenatal vitamins unless your doctor advises otherwise.

At doses above 5 mg daily, folic acid can cause abdominal cramps, diarrhea, rash, bitter taste, confusion, and sleep disturbances. Calcium commonly causes belching, constipation, diarrhea, or stomach upset.

Vitamin C at high doses may cause osmotic diarrhea, kidney stones (especially if prone), nausea, and heartburn. All three are generally well-tolerated in the amounts typically found in supplements and fortified foods.

Side effects, ingredient by ingredient Folic Acid Calcium Vitamin C

Meds to double-check

Major interaction found
Known Interaction Concern · database check
Major identified

At least one ingredient has a documented Major-severity interaction. Check your medications for a personalized result.

Why this rating?
  • 3 of the 3 matched ingredients can interact with medications — Calcium, Vitamin C, Folic Acid.
  • The most serious interaction on file is rated Major.
  • Some involve high-stakes drug classes: anticoagulant / antiplatelet drugs; cancer treatments; heart-rhythm medications; lithium.
  • For scale: 394 individual medications appear in the full list. A big number alone doesn't make a product dangerous — what matters is whether YOUR medication is on it, so run yours through the interaction checker on this page.

Check with your doctor or pharmacist before taking this product if you use HIV integrase inhibitors (dolutegravir, elvitegravir, or raltegravir), anti-seizure medications (phenobarbital, phenytoin, or primidone), cancer drugs (methotrexate, capecitabine, or 5-fluorouracil), thyroid medication (levothyroxine), blood thinners (warfarin), heart medications (sotalol or diltiazem), oral contraceptives, or the antiparasitic pyrimethamine (Daraprim). The calcium and folic acid in this product can reduce how well some of these work or increase their toxicity.

Check your own medication Run your meds through the checker above

The bottom line

Scorecard at a glancePartially disclosed formula with insufficient evidence for its stated purpose. Major medication interactions have been identified, and safety information is well characterized.

If you take anti-seizure medications, chemotherapy, methotrexate, HIV integrase inhibitors, thyroid medication, heart drugs, oral contraceptives, or blood thinners like warfarin, you'll want to review this product with your doctor or pharmacist before starting — the interactions are real and could affect how those medications work. For most other people without those specific medications, the product is generally well-tolerated, but run your complete medication list through the tool on this page to be sure.

Educational only — not medical advice; always confirm with your pharmacist. Our editorial policy · How we use AI

Assessment coverage: 3 of 5 active ingredients matched to our full ingredient reviews (monographs). Based on the product label dated Mar 25, 2013.

This Scorecard evaluates available label information, ingredient evidence, and known medication-safety considerations. It does not independently verify product identity, purity, potency, contamination, or manufacturing quality. How these ratings are computed

At a glance

General information

Key facts about Factor 2 Pre-Workout, straight from the product label.

Brand Force Factor
Market status On market
Date entered into DSLD Mar 25, 2013
DSLD ID 19217
Product type Botanical With Nutrients
Supplement form Capsule
Dietary claims / uses All Other, Structure/Function
Intended target group(s) Adult (18 - 50 Years)
From the label
Everything in this section is reproduced from the manufacturer’s own product label — it’s the label speaking, not HelloPharmacist. We show it so you can see exactly what the maker states; we don’t verify or endorse those statements.

Supplement Facts

The label details for Factor 2 Pre-Workout by Force Factor, sourced from the NIH Dietary Supplement Label Database.

Supplement Facts

Daily Value (DV) Target Group(s):
Adults and children 4 or more years of age
Minimum serving Sizes:
2 Capsule(s)
Maximum serving Sizes:
4 Capsule(s)
Servings per container
60
IngredientAmount% DV
Folic Acid600 mcg150%
Calcium16 mg1%
Vitamin C100 mg167%
Dual Stage Next-Gen NOXplosion1285 mg--
Stage 1-Substrate Input Regeneration Complex0 NP--
Stage 2-Dynamic NOx Enzyme Catalysis System0 NP--

Other ingredients: Cellulose, Magnesium Stearate, Gelatin, FD&C Blue #1, FD&C Red #3, FD&C Yellow #6, FD&C Red #40, Titanium Dioxide

Tap any ingredient to jump to its full detail below.

Label statements
These statements are the manufacturer’s wording, reproduced from the product label — the label is saying it, not HelloPharmacist. We don’t verify or endorse them.
General Statements

Join Team Force Factor Today! Force Factor is more than just the sports nutrition brand of champions - it's a lifestyle and a movement. Trusted by thousands of men and women who have seen the real results our products deliver, Force Factor is dedicated to helping you achieve success and see results every day. Our job is to make you leaner, faster, and stronger - period. {QR CODE} FORCE FACTOR

NEXT-GENERATION NITRIC OXIDE BOOSTER

Product Information You have hundreds of options when it comes to muscle-building supplements. So how do you choose? Untested, unsafe ingredients are not the answer. Risking dangerous, long-term side effects isn't worth any potential short-term gain. Plus, many of those "magical" mystery ingredients pumped into other products end up being useless, wasting your time and money.

You don't need to be a pro to take advantage of the smart science behind Factor 2. Stop experimenting with pills and powder that make you feel like your heart is going to explode. Instead, harness the transformative power of Factor 2.

Enhance Results with Stacking Factor 2 was engineered to deliver powerful muscle-building results on its own, but works even more effectively when stacked with other premium Force Factor products. Maximize your pumps and power by combining Factor 2 with Force Factor.

The L-citrulline in Factor 2 has been shown to be even more effective than L-arginine itself at raising your body's L-arginine levels, stimulating your body's natural NO production as you conquer your toughest workouts. Along with Factor 2's powerful amino acids, vitamin C and calcium work in tandem to help increase the amount of nitric oxide synthase enzyme in your body, catalyzing the NO reaction and deliver incredible stamina, allowing you to see better results than ever before. The science behind Factor 3 is trusted by fitness enthusiasts and professional athletes around the world. Factor 2's high-quality, scientifically studied ingredients work to help you build lean muscle safely for the transformative results you crave.

>>Amplifies Strength, Power, & Stamina >>Delivers Explosive Energy >>Enhances Nutrient Uptake & Delivery

Lot # and Exp. Date:

Suggested/Recommended/Usage/Directions

Usage Workout Days: Take 2-4 capsules with breakfast and 2-4 capsules 30 minutes before working out. Non-Workout Days: Take 2-4 capsules with breakfast and 2-4 capsules with lunch. {image} WORKOUT DAYS breakfast 30 min. before your workout {image} NON-WORKOUT DAYS breakfast lunch

Brand IP Statement(s)

Factor 2(TM) Science Powerful Ingredients, Incredible Results Factor 2's unique formula was created by biologists to help you build strength and power. Not pharmacists or university researchers - scientists serious about formulating the best products in the industry. Their mission for Factor 2: to help you add pounds of lean muscle, gain strength, and achieve the powerful physique you've always wanted during your newly intensified workout routine. The unique blends in Factor 2 work to enhance your body's nitric oxide (NO) levels. With a cutting-edge, multi-targeted pathway to boost NO, Factor 2 in in a class by itself, leading the way for the next generation of hardcore sports nutrition products. Building upon the breakthrough science that launched Force Factor(R), Factor 2 is formulated to help deliver better, longer-lasting pumps, ensuring that you get the ultimate results from your workouts. Stackable with Force Factor for mind-blowing energy and performance, Factor 2 is the powerful, preeminent supplement for helping you build muscle and sculpt the ripped body of your dreams.

Get cut by stacking Factor 2 with BRX(TM) to add lean muscle and blast through your workouts.

Factor2(TM) is different. It was designed by the experts at Force Factor(R) to help you achieve your muscle-building goals safely, efficiently, and effectively. And, its clinically researched ingredients work. They work so well, in fact, that Factor 2 is endorsed by professional athletes who complete at the elite level.

Seals/Symbols

$20 VALUE FREE SAMPLES INSIDE

Precautions

Allergen Warning: Manufactured by equipment which processes products containing milk, eggs, soybeans, wheat, shellfish, fish oil, tree nuts, and peanut flavor.

Precautions: Use only as directed.

Consult your physician before use if you are pregnant or nursing, have a serious medical condition, or use prescription medications.

Formula

For adult use only.

Storage

Protect from heat, light, and moisture. Store at 15-30(0)C (59-86(0)F).

FDA Disclaimer Statement

*These statements have not been evaluated by the FDA. This product is not intended to diagnose, treat, cure, or prevent any disease.

Is this label outdated? Report a formula or label change and our pharmacy team will review it.

See for yourself

Factor 2 Pre-Workout by Force Factor label

The label scan from the NIH Dietary Supplement Label Database. Tap to enlarge.

Factor 2 Pre-Workout label

Label images are published by the NIH Dietary Supplement Label Database for the version of this product on file. Always read your actual product label.

View the full label (PDF)
What’s inside

The Ingredients in Factor 2 Pre-Workout by Force Factor

These are the 5 active ingredients this product is made of. Select any to open its full monograph.

Serving size2 Capsule(s) Dosage formCapsule Servings per container60 Amounts shown are per serving.

Most supplement products combine several ingredients, and a medication can interact with the product through any one of them. Each ingredient below shows whether it has known drug interactions.

Folic Acid

Interacts with
40 drugs
600 mcg per serving

Folic acid is the man-made form of vitamin B9 and is one of the most well-studied supplements, especially for preventing serious birth defects when ta...

Folic Acid monograph & interactions

Calcium

Interacts with
168 drugs
16 mg per serving Form: Calcium Ascorbate

Calcium is an essential mineral your body needs for strong bones, nerve signaling, and muscle function, and supplements can help fill gaps when diet f...

Calcium monograph & interactions

Vitamin C

Interacts with
207 drugs
100 mg per serving Form: Ascorbic Acid

Vitamin C (ascorbic acid) is an essential nutrient your body needs but cannot make, so you must get it from food or supplements. It's important for im...

Vitamin C monograph & interactions

Dual Stage Next-Gen NOXplosion

1285 mg per serving
  • › Stage 1-Substrate Input Regeneration Complex
  • › Stage 2-Dynamic NOx Enzyme Catalysis System

Other (inactive) ingredients: Cellulose, Magnesium Stearate, Gelatin, FD&C Blue #1, FD&C Red #3, FD&C Yellow #6, FD&C Red #40, Titanium Dioxide. These complete the product’s ingredient list but are not active constituents.

Interaction report

Factor 2 Pre-Workout by Force Factor Drug Interactions

Want to check YOUR meds against Factor 2 Pre-Workout?

Ask about interactions with your drugs in plain English — “Can I take it with lisinopril?” — and we find you the answer in seconds, ingredient by ingredient.

 Go to the checker
394Drugs
7 Major 264 Moderate 123 Minor

Ingredients driving the most interactions

Vitamin C 207
Calcium 168
Folic Acid 40

Individual Drug Interactions

The ingredients in Factor 2 Pre-Workout interact with 394 drugs. Click any drug to see the details.

3 of the 5 ingredients in Factor 2 Pre-Workout interact with drugs. Each result below shows which ingredient is responsible. Vitamin C Calcium Folic Acid

Each ingredient & the kinds of drugs it affects

For each ingredient in Factor 2 Pre-Workout with known interactions, here are the types of medications they can affect. Open any type for the detail — or search your exact drug in the checker above.

Vitamin C13 drug types · 207 drugs

Alkylating Agents

Theoretically, antioxidant effects of vitamin C might reduce the effectiveness of alkylating agents.
The use of antioxidants like vitamin C during chemotherapy is controversial. There is concern that antioxidants could reduce the activity of chemotherapy drugs that generate free radicals, such as cyclophosphamide, chlorambucil, carmustine, busulfan, and thiotepa. In contrast, some researchers theorize that antioxidants might make chemotherapy more effective by reducing oxidative stress that could interfere with apoptosis (cell death) of cancer cells. More evidence is needed to determine what effect, if any, antioxidants such as vitamin C have on chemotherapy.

Likelihood Possible Evidence D
Aluminum

Vitamin C can increase the amount of aluminum absorbed from aluminum compounds.
Research in animals and humans shows that vitamin C increases aluminum absorption, theoretically by chelating aluminum and keeping it in solution where it is available for absorption. In people with normal renal function, urinary excretion of aluminum will likely increase, making aluminum retention and toxicity unlikely. Patients with renal failure who take aluminum-containing compounds such as phosphate binders should avoid vitamin C supplements in doses above the recommended dietary allowances.

Likelihood Probable Evidence B
Antitumor Antibiotics

Theoretically, the antioxidant effects of vitamin C might reduce the effectiveness of antitumor antibiotics.
The use of antioxidants like vitamin C during chemotherapy is controversial. There is concern that antioxidants could reduce the activity of chemotherapy drugs which generate free radicals, such as doxorubicin. In contrast, some researchers theorize that antioxidants might make chemotherapy more effective by reducing oxidative stress that could interfere with apoptosis (cell death) of cancer cells. More evidence is needed to determine what effects, if any, antioxidants such as vitamin C have on chemotherapy.

Likelihood Possible Evidence D
Estrogens

Vitamin C might increase blood levels of estrogens.
Increases in plasma estrogen levels of up to 55% occur under some circumstances when vitamin C is taken concurrently with oral contraceptives or hormone replacement therapy, including topical products. It is suggested that vitamin C prevents oxidation of estrogen in the tissues, regenerates oxidized estrogen, and reduces sulfate conjugation of estrogen in the gut wall. When tissue levels of vitamin C are high, these processes are already maximized and supplemental vitamin C does not have any effect on estrogen levels. Increases in plasma estrogen levels may occur when patients who are deficient in vitamin C take supplements. Monitor these patients for estrogen-related side effects.

Likelihood Probable Evidence B
Fluphenazine (Prolixin)

Theoretically, vitamin C might decrease levels of fluphenazine.
In one patient there was a clinically significant decrease in fluphenazine levels when vitamin C (500 mg twice daily) was started. The mechanism is not known, and there is no further data to confirm this interaction.

Likelihood Possible Evidence D
Indinavir (Crixivan)

Vitamin C can modestly reduce indinavir levels.
One pharmacokinetic study shows that taking vitamin C 1 gram orally once daily along with indinavir 800 mg orally three times daily reduces the area under the concentration-time curve of indinavir by 14%. The mechanism of this interaction is unknown, but it is unlikely to be clinically significant in most patients. The effect of higher doses of vitamin C on indinavir levels is unknown.

Likelihood Probable Evidence B
Levothyroxine (Synthroid, Others)

Vitamin C can increase levothyroxine absorption.
Two clinical studies in adults with poorly controlled hypothyroidism show that swallowing levothyroxine with a glass of water containing vitamin C 500-1000 mg in solution reduces thyroid stimulating hormone (TSH) levels and increases thyroxine (T4) levels when compared with taking levothyroxine alone. This suggests that vitamin C increases the oral absorption of levothyroxine, possibly due to a reduction in pH.

Likelihood Probable Evidence B
Warfarin (Coumadin)

High-dose vitamin C might reduce the levels and effectiveness of warfarin.
Vitamin C in high doses may cause diarrhea and possibly reduce warfarin absorption. There are reports of two people who took up to 16 grams daily of vitamin C and had a reduction in prothrombin time. Lower doses of 5-10 grams daily can also reduce warfarin absorption. In many cases, this does not seem to be clinically significant. However, a case of warfarin resistance has been reported for a patient who took vitamin C 500 mg twice daily. Cessation of vitamin C supplementation resulted in a rapid increase in international normalized ratio (INR). Tell patients taking warfarin to avoid taking vitamin C in excessively high doses (greater than 10 grams daily). Lower doses may be safe, but the anticoagulation activity of warfarin should be monitored. Patients who are stabilized on warfarin while taking vitamin C should avoid adjusting vitamin C dosage to prevent the possibility of warfarin resistance.

Likelihood Possible Evidence D
Acetaminophen (Tylenol, Others)

High-dose vitamin C might slightly prolong the clearance of acetaminophen.
A small pharmacokinetic study in healthy volunteers shows that taking high-dose vitamin C (3 grams) 1.5 hours after taking acetaminophen 1 gram slightly increases the apparent half-life of acetaminophen from around 2.3 hours to 3.1 hours. Ascorbic acid competitively inhibits sulfate conjugation of acetaminophen. However, to compensate, elimination of acetaminophen glucuronide and unconjugated acetaminophen increases. This effect is not likely to be clinically significant.

Likelihood Probable Evidence B
Aspirin

Acidification of the urine by vitamin C might increase aspirin levels.
It has been suggested that acidification of the urine by vitamin C could increase reabsorption of salicylates by the renal tubules, and increase plasma salicylate levels. However, short-term use of up to 6 grams daily of vitamin C does not seem to affect urinary pH or salicylate excretion, suggesting this interaction is not clinically significant.

Likelihood Possible Evidence B
Choline Magnesium Trisalicylate (Trilisate)

Acidification of the urine by vitamin C might increase choline magnesium trisalicylate levels.
It has been suggested that acidification of the urine by vitamin C could increase reabsorption of salicylates by the renal tubules, and increase plasma salicylate levels. However, short-term use of up to 6 grams daily of vitamin C does not seem to affect urinary pH or salicylate excretion, suggesting this interaction probably is not clinically significant.

Likelihood Possible Evidence B
Niacin

Vitamin C might decrease the beneficial effects of niacin on high-density lipoprotein (HDL) cholesterol levels.
A combination of niacin and simvastatin (Zocor) effectively raises HDL cholesterol levels in patients with coronary disease and low HDL levels. Clinical research shows that taking a combination of antioxidants (vitamin C, vitamin E, beta-carotene, and selenium) along with niacin and simvastatin (Zocor) attenuates this rise in HDL, specifically the HDL-2 and apolipoprotein A1 fractions, by more than 50% in patients with coronary disease. It is not known whether this adverse effect is due to a single antioxidant such as vitamin C, or to the combination. It also is not known whether it will occur in other patient populations.

Likelihood Possible Evidence A
Salsalate (Disalcid)

Acidification of the urine by vitamin C might increase salsalate levels.
It has been suggested that acidification of the urine by vitamin C could increase reabsorption of salicylates by the renal tubules, and increase plasma salicylate levels. However, short-term use of up to 6 grams/day vitamin C does not seem to affect urinary pH or salicylate excretion, suggesting this interaction probably is not clinically significant.

Likelihood Possible Evidence B
Vitamin C full monograph & interactions

Calcium18 drug types · 168 drugs

Ceftriaxone (Rocephin)

Co-administration of intravenous calcium and ceftriaxone can result in precipitation of a ceftriaxone-calcium salt in the lungs and kidneys.
Avoid administering intravenous calcium in any form, such as parenteral nutrition or Lactated Ringers, within 48 hours of intravenous ceftriaxone. Case reports in neonates show that administering intravenous ceftriaxone and calcium can result in precipitation of a ceftriaxone-calcium salt in the lungs and kidneys. In several cases, neonates have died as a result of this interaction. So far there are no reports in adults; however, there is still concern that this interaction might occur in adults.

Likelihood Probable Evidence D
Dolutegravir (Tivicay)

Calcium seems to reduce levels of dolutegravir.
Advise patients to take dolutegravir either 2 hours before or 6 hours after taking calcium supplements. Pharmacokinetic research suggests that taking calcium carbonate 1200 mg concomitantly with dolutegravir 50 mg reduces plasma levels of dolutegravir by almost 40%. Calcium appears to decrease levels of dolutegravir through chelation.

Likelihood Probable Evidence B
Elvitegravir (Vitekta)

Calcium seems to reduce levels of elvitegravir.
Advise patients to take elvitegravir either 2 hours before or 2 hours after taking calcium supplements. Pharmacokinetic research suggests that taking calcium along with elvitegravir can reduce blood levels of elvitegravir through chelation.

Likelihood Probable Evidence B
Aluminum

Calcium citrate might increase aluminum absorption and toxicity. Other types of calcium do not increase aluminum absorption.
Calcium citrate can increase the absorption of aluminum when taken with aluminum hydroxide. The increase in aluminum levels may become toxic, particularly in individuals with kidney disease. However, the effect of calcium citrate on aluminum absorption is due to the citrate anion rather than calcium cation. Calcium acetate does not appear to increase aluminum absorption.

Likelihood Possible Evidence B
Bictegravir/Emtricitabine/Tenofovir Alafenamide (Biktarvy)

Calcium might decrease levels of bictegravir/emtricitabine/tenofovir alafenamide by reducing its absorption when taken in a fasting state.
Advise patients that bictegravir/emtricitabine/tenofovir alafenamide and calcium can be taken together if taken with food. However, if taken on an empty stomach, bictegravir/emtricitabine/tenofovir alafenamide should not be taken with, or 2 hours after, calcium containing products.

Likelihood Probable Evidence D
Bisphosphonates

Calcium reduces the absorption of bisphosphonates.
Advise patients to take bisphosphonates at least 30 minutes before calcium, but preferably at a different time of day. Calcium supplements decrease absorption of bisphosphonates.

Likelihood Probable Evidence C
Calcipotriene (Dovonex)

Taking calcipotriene with calcium might increase the risk for hypercalcemia.
Calcipotriene is a vitamin D analog used topically for psoriasis. It can be absorbed in sufficient amounts to cause systemic effects, including hypercalcemia. Theoretically, combining calcipotriene with calcium supplements might increase the risk of hypercalcemia.

Likelihood Possible Evidence B
Digoxin (Lanoxin)

Using intravenous calcium with digoxin might increase the risk of fatal cardiac arrhythmias.
Hypercalcemia increases the risk of fatal cardiac arrhythmias with digoxin. However, one retrospective analysis of clinical data suggests that intravenous calcium does not increase the risk of dysrhythmias or mortality in patients receiving digoxin.

Likelihood Possible Evidence B
Diltiazem (Cardizem, Others)

Theoretically, calcium may reduce the therapeutic effects of diltiazem.
Hypercalcemia can reduce the effectiveness of verapamil in atrial fibrillation. Theoretically, calcium might increase this risk of hypercalcemia and reduce the effectiveness of diltiazem.

Likelihood Probable Evidence D
Levothyroxine (Synthroid, Others)

Calcium seems to reduce the absorption and effectiveness of levothyroxine.
Advise patients to take levothyroxine and calcium supplements at least 4 hours apart. Calcium reduces levothyroxine absorption, probably by forming insoluble complexes. Calcium carbonate supplements reduce effectiveness of levothyroxine in patients with hypothyroidism.

Likelihood Probable Evidence B
Lithium

Theoretically, concomitant use of calcium and lithium may increase this risk of hypercalcemia.
Clinical research suggests that long-term use of lithium may cause hypercalcemia in 10% to 60% of patients. Theoretically, concomitant use of lithium and calcium supplements may further increase this risk.

Likelihood Possible Evidence B
Quinolone Antibiotics

Calcium seems to reduce the absorption of quinolone antibiotics.
Advise patients to take oral quinolones at least 2 hours before or 4-6 hours after calcium supplements or calcium-fortified foods. Taking calcium at the same time as oral quinolones can reduce quinolone absorption. Calcium binds to quinolones in the gut.

Likelihood Probable Evidence B
Raltegravir (Isentress)

Calcium may reduce levels of raltegravir.
Pharmacokinetic research shows that taking a single dose of calcium carbonate 3000 mg along with raltegravir 400 mg twice daily modestly decreases the mean area under the curve of raltegravir, but the decrease does not necessitate a dose adjustment of raltegravir. However, a case of elevated HIV-1 RNA levels and documented resistance to raltegravir has been reported for a patient taking calcium carbonate 1 gram three times daily plus vitamin D3 (cholecalciferol) 400 IU three times daily in combination with raltegravir 400 mg twice daily for 11 months. It is thought that calcium reduced raltegravir levels by chelation, leading to treatment failure.

Likelihood Possible Evidence B
Sotalol (Betapace)

Calcium seems to reduce the absorption of sotalol.
Advise patients to separate doses by at least 2 hours before or 4-6 hours after calcium. Calcium appears to reduce the absorption of sotalol, probably by forming insoluble complexes.

Likelihood Possible Evidence B
Tetracycline Antibiotics

Calcium seems to reduce the absorption of tetracycline antibiotics.
Advise patients to take oral tetracyclines at least 2 hours before, or 4-6 hours after calcium supplements. Taking calcium at the same time as oral tetracyclines can reduce tetracycline absorption. Calcium binds to tetracyclines in the gut.

Likelihood Probable Evidence C
Thiazide Diuretics

Taking calcium along with thiazides might increase the risk of hypercalcemia and renal failure.
Thiazides reduce calcium excretion by the kidneys. Using thiazides along with moderately large amounts of calcium carbonate increases the risk of milk-alkali syndrome (hypercalcemia, metabolic alkalosis, renal failure). Patients may need to have their serum calcium levels and/or parathyroid function monitored regularly.

Likelihood Probable Evidence C
Verapamil (Calan, Others)

Theoretically, calcium may reduce the therapeutic effects of verapamil.
Hypercalcemia can reduce the effectiveness of verapamil in atrial fibrillation. Theoretically, use of calcium supplements may increase this risk of hypercalcemia and reduce the effectiveness of verapamil.

Likelihood Probable Evidence D
Calcium Channel Blockers

Intravenous calcium may decrease the effects of calcium channel blockers; oral calcium is unlikely to have this effect.
Intravenous calcium is used to decrease the effects of calcium channel blockers in the management of overdose. Intravenous calcium gluconate has been used before intravenous verapamil (Isoptin) to prevent or reduce the hypotensive effects without affecting the antiarrhythmic effects. But there is no evidence that dietary or supplemental calcium when taken orally interacts with calcium channel blockers.

Likelihood Unlikely Evidence D
Calcium full monograph & interactions

Folic Acid7 drug types · 40 drugs

5-Fluorouracil

Theoretically, high doses of folic acid might increase the toxicity of 5-fluorouracil.
Increases in gastrointestinal side effects of 5-fluorouracil, such as stomatitis and diarrhea, have been described in two clinical studies when leucovorin, a form of folic acid, was administered with 5-fluorouracil.

Likelihood Possible Evidence D
Capecitabine (Xeloda)

Use of high-dose folic acid might contribute to capecitabine toxicity.
Clinical research suggests that higher serum folate levels are associated with an increased risk for moderate or severe toxicity during capecitabine-based treatment for colorectal cancer. Additionally, in one case report, taking folic acid 15 mg daily might have contributed to increased toxicity, including severe diarrhea, vomiting, edema, hand-foot syndrome, and eventually death, in a patient prescribed capecitabine.

Likelihood Possible Evidence D
Methotrexate (Trexall, Others)

Folic acid might reduce the efficacy of methotrexate as a cancer treatment when given concurrently.
Methotrexate exerts its cytotoxic effects by preventing conversion of folic acid to the active form needed by cells. There is some evidence that folic acid supplements reduce the efficacy of methotrexate in the treatment of acute lymphoblastic leukemia, and theoretically they could reduce its efficacy in the treatment of other cancers. Advise cancer patients to consult their oncologist before using folic acid supplements. In patients treated with long-term, low-dose methotrexate for rheumatoid arthritis (RA) or psoriasis, folic acid supplements can reduce the incidence of side effects, without reducing efficacy.

Likelihood Probable Evidence B
Phenobarbital (Luminal)

Folic acid might have antagonistic effects on phenobarbital and increase the risk for seizures.
Folic acid can have direct convulsant activity in some people, reversing the effects of phenobarbital and worsening seizure control. Monitor closely for increased seizure activity.

Likelihood Probable Evidence B
Phenytoin (Dilantin)

Folic acid might reduce serum levels of phenytoin in some patients.
Folic acid may be a cofactor in phenytoin metabolism. Folic acid, in doses of 1 mg daily or more, can reduce serum levels of phenytoin in some patients. Increases in seizure frequency have been reported. If folic acid supplements are added to established phenytoin therapy, monitor serum phenytoin levels closely. If phenytoin and folic acid are started at the same time and continued together, adverse changes in phenytoin pharmacokinetics are avoided. Note that phenytoin also reduces serum folate levels.

Likelihood Probable Evidence B
Primidone (Mysoline)

Folic acid might have antagonistic effects on primidone and increase the risk for seizures.
Folic acid can have direct convulsant activity in some people, reversing the effects of primidone and worsening seizure control. Monitor closely for increased seizure activity. Note that primidone also reduces serum folate levels.

Likelihood Probable Evidence B
Pyrimethamine (Daraprim)

Folic acid might antagonize the effects of pyrimethamine.
Folic acid can antagonize the antiparasitic effects of pyrimethamine against toxoplasmosis and Pneumocystis carinii pneumonia. Folic acid doesn't antagonize the effects of pyrimethamine in the treatment of malaria, because malarial parasites cannot use exogenous folic acid. Use folinic acid as an alternative to folic acid when indicated.

Likelihood Probable Evidence D
Folic Acid full monograph & interactions
The maker

Brand information

Manufacturer and brand details for Factor 2 Pre-Workout, from the product label.

Force Factor

Web Address
www.ForceFactor.com
Pharmacist Counseling Corner

Factor 2 Pre-Workout by Force Factor: Common Questions

Does Factor 2 Pre-Workout by Force Factor interact with any medications?
Yes. Based on its ingredients, Factor 2 Pre-Workout has a known interaction with 394 medications, including 7 rated major. Use the checker to see how it interacts with a specific drug.
How can one product interact with so many drugs?
Factor 2 Pre-Workout contains 5 active ingredients, and an interaction can come from any of them. We check every ingredient, combine the results into one list per medication, and show which ingredient and mechanism is responsible.
Where does this information come from?
The product label data comes from the NIH Dietary Supplement Label Database (DSLD); the interaction data is built on the Natural Medicines database and reviewed by HelloPharmacist pharmacists.
Can I take this while I'm pregnant?
The folic acid in here is recommended during pregnancy at standard prenatal doses to prevent birth defects — that's good. Calcium at normal amounts is also considered important in pregnancy. Vitamin C in normal dietary amounts is fine, but the data advises against high-dose vitamin C supplements during pregnancy unless your doctor says otherwise. Talk with your doctor or pharmacist about whether this product's doses fit your prenatal plan.
What's the folic acid in this for?
Folic acid is a B vitamin that helps prevent folate deficiency and is especially important for preventing neural tube birth defects during pregnancy. It's also used to help reduce some side effects of methotrexate therapy and may help with depression and cognitive issues, though the evidence for those last two is weaker.
Is there a reason I'd get stomach upset from this?
Yes — both folic acid at higher doses and calcium commonly cause abdominal discomfort, diarrhea, or gas. Vitamin C at high doses can also cause heartburn or diarrhea. If you're prone to stomach issues, start with a lower dose to see how you tolerate it, and talk to your pharmacist if side effects don't settle.
Does this have any ingredient I haven't heard of?
The product lists three known ingredients (folic acid, calcium, vitamin C) plus two proprietary blend components — Stage 1-Substrate Input Regeneration Complex and Stage 2-Dynamic NOx Enzyme Catalysis System — whose specific contents aren't broken down on the label. We have no data on those, so we can't check them for interactions.
Will this help my athletic performance?
That depends on the proprietary blend ingredients, which we don't have data on. Folic acid, calcium, and vitamin C each have their own roles in the body — folic acid supports cell function, calcium is critical for muscle contraction and bone strength, and vitamin C is an antioxidant — but we don't have effectiveness information specifically for athletic performance on file for this product.
Can I take this while breastfeeding?
Folic acid at normal recommended doses is considered safe while breastfeeding, as is calcium at recommended amounts. Vitamin C from normal dietary amounts is safe; avoid high-dose supplements unless directed by your healthcare provider. Check the product label for the actual doses and confirm with your doctor or pharmacist that they fit your needs.

Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy

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Label information is sourced from the NIH Dietary Supplement Label Database and reflects the product version on file; always read your actual product label. This page is for education only and is not a substitute for professional medical advice. Confirm with your pharmacist or doctor before combining supplements and medications.

Factor 2 Pre-Workout label
Go deeper

The Full Monographs Behind Factor 2 Pre-Workout’s Ingredients

Every ingredient we hold a full HelloPharmacist monograph for — uses, evidence, safety, and the complete interaction list.

Herb & supplement monograph

Folic Acid

Interacts with 40 drugs

Folic acid is the man-made form of vitamin B9 and is one of the most well-studied supplements, especially for preventing serious birth defects when taken before and during early pregnancy. I...

Read the full Folic Acid monograph → Herb & supplement monograph

Calcium

Interacts with 168 drugs

Calcium is an essential mineral your body needs for strong bones, nerve signaling, and muscle function, and supplements can help fill gaps when diet falls short. Most people do best getting...

Read the full Calcium monograph → Herb & supplement monograph

Vitamin C

Interacts with 207 drugs

Vitamin C (ascorbic acid) is an essential nutrient your body needs but cannot make, so you must get it from food or supplements. It's important for immune function, collagen, and acts as an...

Read the full Vitamin C monograph →
Sources

Sources & How We Checked

Factor 2 Pre-Workout's label data comes from the NIH Dietary Supplement Label Database; the ingredient interaction data is from the Natural Medicines database, reviewed by our pharmacists.

Content is written and reviewed by licensed HelloPharmacist pharmacists. See our data sources and editorial standards for how this information is built and checked.

The 169 references behind this product’s interaction data

Every citation that drives the interaction findings for this product’s ingredients, from the evidence-graded Natural Medicines (TRC Healthcare) database. Open an ingredient to browse its citations — links open the study on PubMed or the publisher’s site.

Folic Acid 56 references
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See these in context on the Folic Acid monograph →

Calcium 62 references
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Parts of this content are provided by the Therapeutic Research Center, LLC.

DISCLAIMER: Currently this does not check for drug-drug interactions. This is not an all-inclusive comprehensive list of potential interactions and is for informational purposes only. Not all interactions are known or well-reported in the scientific literature, and new interactions are continually being reported. Input is needed from a qualified healthcare provider including a pharmacist before starting any therapy. Application of clinical judgment is necessary.

© 2021 Therapeutic Research Center, LLC

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