Interactions on record — worth a quick check against your medications. Based on 1 of 4 ingredients. Check your meds →
Dietary supplement

Mega Primrose Ingredients & Drug Interactions

by Source Naturals

Mega Primrose label
See full label image
Softgel Capsule Category: Fat/fatty Acid
Most serious interaction: Moderate
Clinical methodology reviewed by · Updated Sep 23, 2026 · Label data from the NIH DSLD
What is this page for?

First and foremost: checking Mega Primrose 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

Mega Primrose is a dietary supplement by Source Naturals with 4 active ingredients. Its ingredients are commonly taken for heart health, healthy cooking fat, skin moisturizing.Based on those ingredients, 86 medications have a known interaction with it, the most serious rated moderate. The ingredients most likely to interact are Oleic 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 Mega Primrose by Source Naturals

Ask about any prescription or over-the-counter medication and we check it for interactions with Mega Primrose by Source Naturals — and tell you which ingredient is responsible.

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HelloPharmacist Scorecard of Mega Primrose by Source Naturals

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 Aug 20, 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 4 of its 4 active ingredients.
  • “Oil of Evening Primrose” is listed as a grouped ingredient — the label gives one combined amount (1.35 Gram(s)) without saying how much of each component you get.

Mega Primrose contains 4 active ingredients, all fatty acids from evening primrose oil: gamma-linolenic acid, linoleic acid, oleic acid, and palmitic acid. Evening primrose oil is a traditional source of these omega-6 and monounsaturated fats.

The softgels also contain gelatin, glycerin, and purified water as inactive ingredients to hold and deliver the oil.

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: Maintains cell membranes.
  • Our graded evidence for these ingredients doesn't cover that particular purpose.

Oleic acid — one of the ingredients here — is possibly effective for high cholesterol (hypercholesterolemia) and coronary heart disease. The evidence we hold doesn't establish effectiveness for the other ingredients in this product or for any other conditions.

The evidence, ingredient by ingredient Oleic Acid

How safe is it?

Some data gaps
Safety Information · database check
Some gaps

Safety data exists for these ingredients, but with some important gaps.

Why this rating?
  • We hold adverse-effect (side-effect) data for 0 of the 1 matched ingredient.
  • Pregnancy & breastfeeding safety ratings cover 1 of 1.
  • General safety write-ups exist for 1 of 1.
  • Remember: this measures how much safety information exists. Thin data is not the same as being safe.

Oleic acid is generally recognized as safe when you eat it in the amounts found in foods like olive oil. Concentrated supplement doses haven't been well studied in pregnancy or during breastfeeding.

If you're pregnant or nursing, there isn't enough data to know whether supplement-level doses of oleic acid are safe — talk with your doctor or pharmacist before taking this product. No adverse effects are documented in the data we hold.

Side effects, ingredient by ingredient Oleic Acid

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?
  • 1 of the 1 matched ingredient can interact with medications — Oleic Acid.
  • The most serious interaction on file is rated Moderate.
  • Some involve high-stakes drug classes: diabetes medications.
  • For scale: 86 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 exact antidiabetes drugs (blood sugar medications) before starting this product — oleic acid may increase their effects and lower your blood glucose more than intended. We could not check three other ingredients (gamma-linolenic acid, linoleic acid, and palmitic acid) for interactions, so run your full medication list through the checker below.

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 some safety-information gaps remain.

Mega Primrose might interest you if you're looking at evening primrose oil for cholesterol or heart health, since oleic acid shows some promise for both. If you take any antidiabetes medication, check with your doctor or pharmacist first — the oleic acid here could boost how well those drugs work.

If you're pregnant or breastfeeding, ask your doctor or pharmacist whether this product is right for you.

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

Assessment coverage: 1 of 4 active ingredients matched to our full ingredient reviews (monographs). Based on the product label dated Feb 26, 2020.

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 Mega Primrose, straight from the product label.

Brand Source Naturals
Barcode (UPC) 021078010098
Net contents 60 Softgel(s)
Market status On market
Date entered into DSLD Feb 26, 2020
DSLD ID 213834
Product type Fat/fatty Acid
Supplement form Softgel Capsule
Dietary claims / uses Nutrient, All Other, Structure/Function
Intended target group(s) Adult Female (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 Mega Primrose by Source Naturals, 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 Softgel(s)
Maximum serving Sizes:
1 Softgel(s)
UPC/BARCODE
021078010098
IngredientAmount% DV
Calories15 Calorie(s)--
Calories from Fat10 Calorie(s)--
Trans Fat0 Gram(s)--
Total Fat1.5 Gram(s)2%
Gamma-Linolenic Acid135 mg--
Saturated Fat0 Gram(s)--
Linoleic Acid945 mg--
Oleic Acid68 mg--
Palmitic Acid68 mg--
Oil of Evening Primrose1.35 Gram(s)--

Other ingredients: Gelatin, Glycerin, purified Water

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.
Formula

1,350 mg (135 mg of GLA)

Source Naturals eternal woman is a revolutionary line designed so that women may experience the freedom to change naturally.

Our mega primrose softgels contain gamma-linolenic acid (GLA) and linolenic acid, which are polyunsaturated fatty acids. These compounds are used by most cells to produce soothing prostaglandins (intracellular hormone-like messengers), which help maintain the balance of many functions in the body.

Formulation

Maintains cell membranes

FDA Statement of Identity

Dietary Supplement

Suggested/Recommended/Usage/Directions

Suggested Use: 1 softgel 1 to 4 times daily.

Storage

Store in a cool, dry place.

Precautions

Note: If you are pregnant, may become pregnant, or breastfeeding, consult your health care professional before using this product.

Do not use if either tamper-evident seal is broken or missing.

Keep out of the reach of children.

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.

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

See for yourself

Mega Primrose by Source Naturals label

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

Mega Primrose 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 Mega Primrose by Source Naturals

These are the 4 active ingredients this product is made of. Select any to open its full monograph.

Serving size1 Softgel(s) Dosage formSoftgel Capsule 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.

Oil of Evening Primrose

1.35 Gram(s) per serving
  • › Gamma-Linolenic Acid
  • › Linoleic Acid
  • › Oleic Acid
  • › Palmitic Acid

Other (inactive) ingredients: Gelatin, Glycerin, Purified Water. These complete the product’s ingredient list but are not active constituents.

Interaction report

Mega Primrose by Source Naturals Drug Interactions

Want to check YOUR meds against Mega Primrose?

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
86Drugs
86 Moderate

Ingredients driving the most interactions

Oleic Acid 86

Individual Drug Interactions

The ingredients in Mega Primrose interact with 86 drugs. Click any drug to see the details.

1 of the 4 ingredients in Mega Primrose interact with drugs. Each result below shows which ingredient is responsible. Oleic Acid

Each ingredient & the kinds of drugs it affects

For each ingredient in Mega Primrose with known interactions, here are the types of medications it can affect. Open any type for the detail — or search your exact drug in the checker above.

Oleic Acid1 drug type · 86 drugs

Antidiabetes Drugs

Theoretically, oleic acid might increase the effects of antidiabetes drugs. Preliminary clinical research in patients with type 2 diabetes taking oral hypoglycemic drugs shows that eating a diet rich in oleic acid from olive oil decreases fasting blood glucose levels when compared to eating a diet rich in linoleic acid from sunflower oil. It is unknown if taking oleic acid supplements would have this effect or if this change is clinically significant. Until more is known, use caution. Dose adjustment may be necessary. Some antidiabetes drugs include glimepiride (Amaryl), glyburide (DiaBeta, Glynase PresTab, Micronase), insulin, metformin (Glucophage), pioglitazone (Actos), rosiglitazone (Avandia), and others.

Likelihood Possible Evidence B
Oleic Acid full monograph & interactions
The maker

Brand information

Manufacturer and brand details for Mega Primrose, from the product label.

Source Naturals

Name
Source Naturals, Inc.
Street Address
P. O. Box 2118
City
Santa Cruz
State
CA
ZipCode
95062
Web Address
www.sourcenaturals.com
Pharmacist Counseling Corner

Mega Primrose by Source Naturals: Common Questions

Does Mega Primrose by Source Naturals interact with any medications?
Yes. Based on its ingredients, Mega Primrose has a known interaction with 86 medications. Use the checker to see how it interacts with a specific drug.
How can one product interact with so many drugs?
Mega Primrose contains 4 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.
What is evening primrose oil, and what does it do?
Evening primrose oil is a blend of fatty acids — including gamma-linolenic acid, linoleic acid, oleic acid, and palmitic acid. Oleic acid in this product is possibly effective for high cholesterol and coronary heart disease. The evidence we hold doesn't establish what the other fatty acids do.
Can I take this if I'm pregnant or breastfeeding?
Amounts of oleic acid in normal foods are considered safe, but concentrated supplement doses haven't been well studied in pregnancy or while breastfeeding. Talk with your doctor or pharmacist — they can advise whether it's right for you based on your situation.
What if I take diabetes medication?
Oleic acid in this product may increase the effects of antidiabetes drugs, potentially lowering your blood glucose more than expected. Talk with your doctor or pharmacist before starting — they may want to watch your blood sugar more closely if you do take it together.
Does this product have side effects?
No adverse effects are documented in the data we hold for the ingredients in this product. That said, if you notice anything unusual after starting it, let your doctor or pharmacist know.
What's in the softgel capsule besides the oil?
The capsule itself is gelatin, and it's filled with glycerin and purified water along with the evening primrose oil. Those are inactive ingredients — they don't contribute to the product's effects.

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

Not sure if Mega Primrose is safe with your meds?

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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.

Mega Primrose label
Go deeper

The Full Monographs Behind Mega Primrose’s Ingredients

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

Herb & supplement monograph

Oleic Acid

Interacts with 86 drugs

Oleic acid is a heart-healthy monounsaturated fat found mainly in olive oil, canola oil, avocados, and nuts. As part of a Mediterranean-style diet, it is widely viewed as a healthier replace...

Read the full Oleic Acid monograph →
Sources

Sources & How We Checked

Mega Primrose'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 19 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.

Oleic Acid 19 references
  1. Madigan C, Ryan M, Owens D, et al. Dietary unsaturated fatty acids in type 2 diabetes: higher levels of postprandial lipoprotein on a linoleic acid-rich sunflower oil diet compared with an oleic acid-rich olive oil diet. Diabetes Care 2000;23:1472-7. PubMed
  2. Gillingham, L. G., Gustafson, J. A., Han, S. Y., Jassal, D. S., and Jones, P. J. High-oleic rapeseed (canola) and flaxseed oils modulate serum lipids and inflammatory biomarkers in hypercholesterolaemic subjects. Br J Nutr 2011;105(3):417-427. PubMed
  3. Jones PJ, Senanayake VK, Pu S, Jenkins DJ, Connelly PW, Lamarche B, Couture P, Charest A, Baril-Gravel L, West SG, Liu X, Fleming JA, McCrea CE, Kris-Etherton PM. DHA-enriched high-oleic acid canola oil improves lipid profile and lowers predicted cardiova
  4. Cater, N. B., Heller, H. J., and Denke, M. A. Comparison of the effects of medium-chain triacylglycerols, palm oil, and high oleic acid sunflower oil on plasma triacylglycerol fatty acids and lipid and lipoprotein concentrations in humans. Am.J Clin.Nutr PubMed
  5. Mozaffarian D, Clarke R. Quantitative effects on cardiovascular risk factors and coronary heart disease risk of replacing partially hydrogenated vegetable oils with other fats and oils. Eur J Clin Nutr. 2009;63(Suppl 2):S22-33. PubMed
  6. Cao Y, Hou L, Wang W. Dietary total fat and fatty acids intake, serum fatty acids and risk of breast cancer: A meta-analysis of prospective cohort studies. Int J Cancer. 2016;138(8):1894-904. doi: 10.1002/ijc.29938. PubMed
  7. FDA completes review of qualified health claim petition for oleic acid and the risk of coronary heart disease. November 2018. Available at: www.fda.gov/Food/NewsEvents/ConstituentUpdates/ucm624758.htm. Accessed January 25, 2019.
  8. Liu X, Kris-Etherton PM, West SG, et al. Effects of canola and high-oleic-acid canola oils on abdominal fat mass in individuals with central obesity. Obesity. 2016;24(11):2261-2268. PubMed
  9. Bowen KJ, Kris-Etherton PM, West SG, et al. Diets enriched with conventional or high-oleic acid canola oils lower atherogenic lipids and lipoproteins compared to a diet with a western fatty acid profile in adults with central adiposity. J Nutr. 2019;149(3 PubMed
  10. Steffen BT, Duprez D, Szklo M, Guan W, Tsai MY. Circulating oleic acid levels are related to greater risks of cardiovascular events and all-cause mortality: The Multi-Ethnic Study of Atherosclerosis. J Clin Lipidol. 2018;12(6):1404-1412. PubMed
  11. Banim PJ, Luben R, Khaw KT, Hart AR. Dietary oleic acid is inversely associated with pancreatic cancer - Data from food diaries in a cohort study. Pancreatology. 2018;18(6):655-660. PubMed
  12. Morin SJ, Gaziano JM, Djoussé L. Relation between plasma phospholipid oleic acid and risk of heart failure. Eur J Nutr. 2018;57(8):2937-2942. PubMed
  13. Samieri C, Féart C, Proust-Lima C, et al. Olive oil consumption, plasma oleic acid, and stroke incidence: the Three-City Study. Neurology. 2011;77(5):418-25. PubMed
  14. Compher CW, Kinosian BP, Rubesin SE, Ratcliffe SJ, Metz DC. Energy absorption is reduced with oleic acid supplements in human short bowel syndrome. JPEN J Parenter Enteral Nutr. 2009;33(1):102-8. PubMed
  15. Ben Fradj MK, Ouanes Y, Hadj-Taieb S, et al. Decreased oleic acid and marine n?-?3 polyunsaturated fatty acids in Tunisian patients with urothelial bladder cancer. Nutr Cancer. 2018;70(7):1043-1050.
  16. de Silva PS, Luben R, Shrestha SS, Khaw KT, Hart AR. Dietary arachidonic and oleic acid intake in ulcerative colitis etiology: a prospective cohort study using 7-day food diaries. Eur J Gastroenterol Hepatol. 2014;26(1):11-8. PubMed
  17. Higashi K, Shige H, Ito T, et al. Effect of a low-fat diet enriched with oleic acid on postprandial lipemia in patients with type 2 diabetes mellitus. Lipids. 2001;36(1):1-6. PubMed
  18. Lin HC, van Citters GW, Heimer F, Bonorris G. Slowing of gastrointestinal transit by oleic acid: a preliminary report of a novel, nutrient-based treatment in humans. Dig Dis Sci. 2001;46(2):223-9. PubMed
  19. Li D, Tong Y, Li Y. Associations between dietary oleic acid and linoleic acid and depressive symptoms in perimenopausal women: The Study of Women's Health Across the Nation. Nutrition. 2020 Mar;71:110602. PubMed

See these in context on the Oleic Acid monograph →

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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