Interactions on record — worth a quick check against your medications. Check your meds →
Dietary supplement

Pregnenolone 30 mg Ingredients & Drug Interactions

by Country Life

Pregnenolone 30 mg label
See full label image
Capsule Category: Other Combinations
Most serious interaction: Moderate
Clinical methodology reviewed by · Updated Sep 16, 2026 · Label data from the NIH DSLD
What is this page for?

First and foremost: checking Pregnenolone 30 mg 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: Moderate

Pregnenolone 30 mg is a dietary supplement by Country Life with 2 active ingredients. Its ingredients are commonly taken for common cold and immune support, antioxidant support, skin health and collagen formation.Based on those ingredients, 248 medications have a known interaction with it, the most serious rated moderate. The ingredients most likely to interact are Vitamin C, Pregnenolone. Use the checker below to test your specific medication, or read the full HelloPharmacist Interaction Report.

Jump to a section

Check Your Meds Against Pregnenolone 30 mg by Country Life

Ask about any prescription or over-the-counter medication and we check it for interactions with Pregnenolone 30 mg by Country Life — and tell you which ingredient is responsible.

Pharmacist-reviewed data Checks every ingredient Answer in seconds
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HelloPharmacist Scorecard of Pregnenolone 30 mg by Country Life

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 11, 2026

What’s inside

Full disclosure
Ingredient Transparency · database check
Full

Every active ingredient lists its own amount on the label.

Why this rating?
  • The label discloses an exact amount for 2 of its 2 active ingredients.
  • “Vitamin C” is listed as a grouped ingredient — the label gives one combined amount (42 mg) without saying how much of each component you get.

This product contains two active ingredients: Ascorbyl Palmitate (a fat-soluble form of vitamin C) and Pregnenolone at 30 mg per capsule. Vitamin C is an essential nutrient that plays a role in immune function and collagen formation.

Pregnenolone is a hormone precursor—your body can convert it into other hormones like estrogen, progesterone, and testosterone. The capsule also contains inactive ingredients (cellulose, stearic acid, magnesium stearate, and silica) that help form and preserve the supplement.

Does it work?

Couldn't assess
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
Not assessable

We hold no graded evidence for this product's ingredients for its stated purpose.

Why this rating?
  • The label markets this product for: support hormone production.
  • Our graded evidence for these ingredients doesn't cover that particular purpose.

Vitamin C has established effectiveness for preventing and treating vitamin C deficiency, and possibly effective evidence for anemia of chronic disease, atrial fibrillation, cataracts, and exercise-induced respiratory infections. Pregnenolone, however, has insufficient evidence to rate its usefulness for the conditions studied so far—alcohol use disorder, Alzheimer disease, autism spectrum disorder, back pain, and bipolar disorder.

The evidence we hold does not establish whether it works for these or any other purposes.

The evidence, ingredient by ingredient Vitamin C Pregnenolone

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 2 of the 2 matched ingredients.
  • Pregnancy & breastfeeding safety ratings cover 2 of 2.
  • General safety write-ups exist for 2 of 2.
  • Remember: this measures how much safety information exists. Thin data is not the same as being safe.

Vitamin C is generally well tolerated at normal supplement doses, but doses above 2 grams daily can cause abdominal cramps, heartburn, diarrhea, nausea, and vomiting. At very high doses (especially intravenous), it may increase kidney stone risk and damage to kidney function, particularly in people with existing kidney disease.

Pregnenolone is generally well tolerated when taken orally, though it can cause acne, agitation, drowsiness, hair loss, tremor, and sweating. Because pregnenolone is a hormone with limited human safety data, the facts advise using it only under guidance from a healthcare professional.

Side effects, ingredient by ingredient Vitamin C Pregnenolone

Meds to double-check

Moderate interaction found
Known Interaction Concern · database check
Moderate identified

The most serious documented interaction for these ingredients is Moderate. Check your medications for a personalized result.

Why this rating?
  • 2 of the 2 matched ingredients can interact with medications — Pregnenolone, Vitamin C.
  • The most serious interaction on file is rated Moderate.
  • Some involve high-stakes drug classes: anticoagulant / antiplatelet drugs; cancer treatments.
  • For scale: 248 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 your medications if you take estrogens (birth control or hormone therapy), the blood thinner warfarin, chemotherapy drugs (especially alkylating agents and antitumor antibiotics), the thyroid drug levothyroxine, benzodiazepines, the antipsychotic fluphenazine, aluminum supplements, the HIV drug indinavir, or progestin, progesterone, or testosterone hormones. Use the search tool to verify your exact prescriptions.

Check your own medication Run your meds through the checker above

The bottom line

Scorecard at a glanceFully disclosed formula with no assessable stated purpose. Moderate medication interactions have been identified, and safety information is well characterized.

This product combines a vitamin (ascorbyl palmitate) with a hormone precursor (pregnenolone) and has significant interactions with hormonal medications, blood thinners, chemotherapy drugs, and sedatives. If you take any prescription medication—especially birth control, hormone therapy, warfarin, thyroid medication, or benzodiazepines—check your specific drugs with the tool on this page before starting.

Because pregnenolone is a hormone with limited safety data, talk with your pharmacist or doctor before use.

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

Assessment coverage: 2 of 2 active ingredients matched to our full ingredient reviews (monographs). Based on the product label dated Mar 25, 2025.

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 Pregnenolone 30 mg, straight from the product label.

Brand Country Life
Barcode (UPC) 015794017059
Net contents 60 Vegan Capsule(s)
Market status On market
Date entered into DSLD Mar 25, 2025
DSLD ID 326835
Product type Other Combinations
Supplement form Capsule
Dietary claims / uses All Other, Structure/Function
Intended target group(s) Vegan, Vegetarian, Adult (18 - 50 Years), Women (not pregnant or lactating), Gluten Free, Dairy Free
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 Pregnenolone 30 mg by Country Life, 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:
1 Capsule(s)
Maximum serving Sizes:
1 Capsule(s)
Servings per container
60
UPC/BARCODE
015794017059
IngredientAmount% DV
Vitamin C42 mg47%
Ascorbyl Palmitate100 mg--
Pregnenolone30 mg--

Other ingredients: Cellulose, Stearic Acid, Magnesium Stearate, Silica

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.
Suggested/Recommended/Usage/Directions

Directions: Adults take one (1) capsule daily with food or as directed by a health care professional.

Precautions

As a reminder, discuss the supplements and medications that you take with your health care providers. Do not use if pregnant or nursing or if you are a women of childbearing age. Consult a physician or licensed qualified health care professional before using this product, if you have, or have a family history of, prostate cancer, prostate enlargement, heart disease, low 'good' cholesterol (HDL), are under medical care, are a women under the age of 40, have or are at risk for a health or medical condition, or if you are using any other dietary supplement, prescription drug or over-the-counter drug (medications) or planning surgery.

Warning: Not for use by persons under the age of 18 years. Keep out of reach of children.

Do not exceed recommended serving. Exceeding recommended serving may cause serious adverse health effects. Possible side effects include acne, oily skin, hair loss, hair growth on the face (in women), increased perspiration, aggressiveness, irritability and increased levels of estrogen. Discontinue use and call a physician or licensed qualified health care professional immediately if you experience rapid heartbeat, dizziness, blurred vision or other similar symptoms. To report any adverse events call 1-800-332-1088. Do not accept if seal is broken.

Storage

Store in a dry place between 59 degrees - 86 degrees F.

Formulation

Pregnenolone plays a supporting role in the production of hormones. This product has been manufactured at a GMP Registered facility.

Yes Certified Vegan by the AVA

Yes Certified Gluten-Free by GFCO.org No Yeast or wheat No Soy or milk No Salt or sugar No Preservatives No Artificial colors No GMOs

Certified Gluten-Free

Supports the production of hormones

Our Pledge of Integrity Authenticity Cleanliness Freshness Consistency Accuracy

Seals/Symbols

Certified B Corporation GF Certified Gluten-Free

FDA Disclaimer Statement

These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure or prevent any disease.

Brand IP Statement(s)

Established 1971 Country Life

FDA Statement of Identity

Dietary Supplement

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

See for yourself

Pregnenolone 30 mg by Country Life label

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

Pregnenolone 30 mg 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 Pregnenolone 30 mg by Country Life

These are the 2 active ingredients this product is made of. Select any to open its full monograph.

Serving size1 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.

Vitamin C

Interacts with
207 drugs
42 mg per serving

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

Pregnenolone

Interacts with
82 drugs
30 mg per serving

Pregnenolone is a hormone your body makes naturally and a building block for other hormones like cortisol, DHEA, estrogen, and testosterone. It is sol...

Pregnenolone monograph & interactions

Other (inactive) ingredients: Cellulose, Stearic Acid, Magnesium Stearate, Silica. These complete the product’s ingredient list but are not active constituents.

Interaction report

Pregnenolone 30 mg by Country Life Drug Interactions

Want to check YOUR meds against Pregnenolone 30 mg?

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
248Drugs
142 Moderate 106 Minor

Ingredients driving the most interactions

Vitamin C 207
Pregnenolone 82

Individual Drug Interactions

The ingredients in Pregnenolone 30 mg interact with 248 drugs. Click any drug to see the details.

2 of the 2 ingredients in Pregnenolone 30 mg interact with drugs. Each result below shows which ingredient is responsible. Vitamin C Pregnenolone

Each ingredient & the kinds of drugs it affects

For each ingredient in Pregnenolone 30 mg 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

Pregnenolone5 drug types · 82 drugs

Benzodiazepines

Concomitant use of pregnenolone may reduce the effects of benzodiazepines.
Very preliminary clinical research shows that chronic use of pregnenolone reduces sedative effects of diazepam when compared with chronic use of placebo. This effect may be related to the activity of pregnenolone at GABAA receptors.

Likelihood Probable Evidence B
Estrogens

Theoretically, taking pregnenolone might enhance the effects of estrogens.
Pregnenolone is a precursor for several steroid hormones, including estrogens.

Likelihood Possible Evidence D
Progesterone

Theoretically, taking pregnenolone might enhance the effects of progesterone.
In humans, some research shows that oral administration of pregnenolone can increase levels of progesterone. However, other research shows no effect on progesterone levels. It is possible the impact of pregnenolone on progesterone levels may be dose dependent.

Likelihood Possible Evidence D
Progestin

Theoretically, taking pregnenolone might enhance the effects of progestin.
Pregnenolone is a precursor for several steroid hormones, including progestin.

Likelihood Possible Evidence D
Testosterone

Theoretically, taking pregnenolone might enhance the effects of testosterone.
Pregnenolone is a precursor for several steroid hormones, including testosterone. However, preliminary clinical research shows that taking pregnenolone 30-500 mg orally daily for up to 8 weeks does not affect testosterone levels.

Likelihood Possible Evidence D
Pregnenolone full monograph & interactions
The maker

Brand information

Manufacturer and brand details for Pregnenolone 30 mg, from the product label.

Country Life

See all Country Life products
Name
Country Life, LLC
Street Address
180 Vanderbilt Motor Parkway
City
Hauppauge
State
NY
ZipCode
11788
Web Address
CountryLifeVitamins.com
Pharmacist Counseling Corner

Pregnenolone 30 mg by Country Life: Common Questions

Does Pregnenolone 30 mg by Country Life interact with any medications?
Yes. Based on its ingredients, Pregnenolone 30 mg has a known interaction with 248 medications. Use the checker to see how it interacts with a specific drug.
How can one product interact with so many drugs?
Pregnenolone 30 mg contains 2 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.
Does pregnenolone really work for memory or brain health?
The evidence we hold shows insufficient data to rate pregnenolone for Alzheimer disease or other brain conditions. Studies haven't yet established whether it's effective for these uses.
Can I take this if I'm on birth control?
No—this product contains vitamin C, which can raise your birth control hormone levels by up to 55%, and pregnenolone, which may enhance estrogen effects. You need to talk with your pharmacist or doctor before combining them.
What are the side effects of pregnenolone?
The most common side effects are acne, agitation, drowsiness, hair loss, tremor, and sweating. Skin rashes and changes in mood or appetite have also been reported with use.
Is high-dose vitamin C in this product a concern?
This capsule contains vitamin C as ascorbyl palmitate (a form of vitamin C), but the product facts don't state the exact dose. At doses above 2 grams daily, vitamin C can cause heartburn, diarrhea, and nausea, and at very high doses, kidney stone risk. Talk to your pharmacist about the actual amount in this formulation.
Can I take this while pregnant or breastfeeding?
The vitamin C in this product is considered likely safe during pregnancy at normal dietary amounts, but avoid high-dose supplements unless your doctor advises it. Pregnenolone should be avoided during pregnancy and breastfeeding because safety data is insufficient. Talk with your doctor before use if you're pregnant or nursing.
Will this interact with my thyroid medication?
Yes—the vitamin C in this product can increase absorption of levothyroxine (Synthroid and others), which may raise your thyroid hormone levels. If you take thyroid medication, check with your pharmacist before adding this product.

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.

Pregnenolone 30 mg label
Go deeper

The Full Monographs Behind Pregnenolone 30 mg’s Ingredients

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

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 → Herb & supplement monograph

Pregnenolone

Interacts with 82 drugs

Pregnenolone is a hormone your body makes naturally and a building block for other hormones like cortisol, DHEA, estrogen, and testosterone. It is sold as a supplement for memory, mood, and...

Read the full Pregnenolone monograph →
Sources

Sources & How We Checked

Pregnenolone 30 mg'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 57 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.

Vitamin C 51 references
  1. McEvoy GK, ed. AHFS Drug Information. Bethesda, MD: American Society of Health-System Pharmacists, 1998.
  2. Back DJ, Breckenridge AM, MacIver M, et al. Interaction of ethinyloestradiol with ascorbic acid in man. Br Med J (Clin Res Ed) 1981;282:1516.
  3. Morris JC, Beeley L, Ballantine N. Interaction of ethinyloestradiol with ascorbic acid in man [letter]. Br Med J (Clin Res Ed) 1981;283:503.
  4. Labriola D, Livingston R. Possible interactions between dietary antioxidants and chemotherapy. Oncology 1999;13:1003-8.
  5. Dwyer JH, Merz NB, Shirocre AM, et al. Progression of early atherosclerosis and intake of vitamin C and vitamin E from supplements and food. The Los Angeles Atherosclerosis Study. 41st Annual Conference on Cardiovascular Disease Epidemiology and Prevent
  6. Levine M, Rumsey SC, Daruwala R, et al. Criteria and recommendations for vitamin C intake. JAMA 1999;281:1415-23. PubMed
  7. Hansten PD, Horn JR. Drug Interactions Analysis and Management. Vancouver, WA: Applied Therapeutics Inc., 1997 and updates.
  8. Segal S, Kaminski S. Drug-nutrient interactions. American Druggist 1996 Jul;42-8.
  9. Food and Nutrition Board, Institute of Medicine. Dietary Reference Intakes for Vitamin C, Vitamin E, Selenium, and Carotenoids. Washington, DC: National Academy Press, 2000. Available at: http://www.nap.edu/books/0309069351/html/.
  10. Houston JB, Levy G. Drug biotransformation interactions in man VI: Acetaminophen and ascorbic acid. J Pharm Sci 1976;65:1218-21. PubMed
  11. Brown BG, Zhao XQ, Chait A, et al. Simvastatin and niacin, antioxidant vitamins, or the combination for the prevention of coronary disease. N Engl J Med 2001;345:1583-93. DOI
  12. Rosenthal G. Interaction of ascorbic acid and warfarin. JAMA 1971;215:1671. DOI
  13. Hume R, Johnstone JM, Weyers E. Interaction of ascorbic acid and warfarin. JAMA 1972;219:1479. DOI
  14. Smith EC, Skalski RJ, Johnson GC, Rossi GV. Interaction of ascorbic acid and warfarin. JAMA 1972;221:1166. DOI
  15. Traxer O, Huet B, Poindexter J, et al. Effect of ascorbic acid consumption on urinary stone risk factors. J Urol 2003;170:397-401.. PubMed
  16. Domingo JL, Gomez M, Llobet JM, Richart C. Effect of ascorbic acid on gastrointestinal aluminum absorption (letter). Lancet 1991;338:1467.
  17. Domingo JL, Gomez M, Llobet JM, Corbella J. Influence of some dietary constituents on aluminum absorption and retention in rats. Kidney Int 1991;39:598-601. PubMed
  18. Partridge NA, Regnier FE, White JL, Hem SL. Influence of dietary constituents on intestinal absorption of aluminum. Kidney Int 1989;35:1413-7. PubMed
  19. Mc Leod DC, Nahata MC. Inefficacy of ascorbic acid as a urinary acidifier (letter). N Engl J Med 1977;296:1413. DOI
  20. Hansten PD, Hayton WL. Effect of antacid and ascorbic acid on serum salicylate concentration. J Clin Pharmacol 1980;20:326-31. PubMed
  21. Dysken MW, Cumming RJ, Channon RA, Davis JM. Drug interaction between ascorbic acid and fluphenazine. JAMA 1979;241:2008. DOI
  22. Vihtamaki T, Parantainen J, Koivisto AM, et al. Oral ascorbic acid increases plasma oestradiol during postmenopausal hormone replacement therapy. Maturitas 2002;42:129-35. PubMed
  23. Slain D, Amsden JR, Khakoo RA, et al. Effect of high-dose vitamin C on the steady-state pharmacokinetics of the protease inhibitor indinavir in healthy volunteers. Pharmacotherapy 2005;25:165-70. PubMed
  24. Cheung MC, Zhao XQ, Chait A, et al. Antioxidant supplements block the response of HDL to simvastatin-niacin therapy in patients with coronary artery disease and low HDL. Arterioscler Thromb Vasc Biol 2001;21:1320-6. PubMed
  25. Feetam CL, Leach RH, Meynell MJ. Lack of a clinically important interaction between warfarin and ascorbic acid. Toxicol Appl Pharmacol 1975;31:544-7. PubMed
  26. Weintraub M, Griner PF. Warfarin and ascorbic acid: lack of evidence for a drug interaction. Toxicol Appl Pharmacol 1974;28:53-6. PubMed
  27. Lee DH, Folsom AR, Harnack L, et al. Does supplemental vitamin C increase cardiovascular disease risk in women with diabetes? Am J Clin Nutr 2004;80:1194-200. PubMed
  28. Taylor EN, Stampfer MJ, Curhan GC. Dietary factors and the risk of incident kidney stones in men: new insights after 14 years of follow-up. J Am Soc Nephrol 2004;15:3225-32. PubMed
  29. Ward NC, Hodgson JM, Croft KD, et al. The combination of vitamin C and grape-seed polyphenols increases blood pressure: a randomized, double-blind, placebo-controlled trial. J Hypertens 2005;23:427-34.. PubMed
  30. Prasad KN. Rationale for using high-dose multiple dietary antioxidants as an adjunct to radiation therapy and chemotherapy. J Nutr 2004;134:3182S-3S. PubMed
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See these in context on the Vitamin C monograph →

Pregnenolone 6 references
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See these in context on the Pregnenolone monograph →

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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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