Drug & supplement interaction

Algal Oil + Finasteride

Finasteride brand names: Propecia, Proscar.

No Known Interaction
The bottom line No known interaction

We found no known interaction between Algal Oil and Finasteride in our sources. Absence of a documented interaction is not the same as proven safety, and does not guarantee one does not exist. Do not start, stop, or change a medication or supplement based on this page; confirm with your pharmacist or doctor first. Additionally, although there is no interaction, the two are separately associated with some of the same side effects, which would make a new symptom harder to attribute to one or the other.

Know someone taking this? Share
Interaction report

Algal Oil and Finasteride

We checked these two against our interaction database. Here is what we found.

No Known Interaction Found

We did not find a documented interaction between Finasteride and Algal Oil in our sources. This does not guarantee that the combination is completely free of risk — there is often limited research on supplements and herbal products, especially around drug interactions.

If you decide to take both, the practical routine is simple: add one new thing at a time and note the date you started it. If the combination is going to disagree with you, it usually shows in the first days to a couple of weeks — and a start date turns “I’ve been feeling off” into something a pharmacist can actually work with. Do not stop a prescribed medicine on your own.

Always talk with your pharmacist or doctor before making changes to your medications or supplements, particularly if you take several medications or have an ongoing health condition.

Algal Oil safety at a glance

Algal Oil overall Generally safe Generally well tolerated by most healthy adults at typical supplement doses.
Pregnancy Likely Safe When used orally and appropriately. Docosahexaenoic acid (DHA)-enriched algal oil is commonly included as a component of prenatal vitamins. Algal oil providing... Read the full pregnancy detail
Breastfeeding Likely Safe When used orally and appropriately. Docosahexaenoic acid (DHA)-enriched algal oil is commonly included as a component of prenatal vitamins. Algal oil providing... Read the full breastfeeding detail

Pregnancy & breastfeeding ratings are from Natural Medicines (Therapeutic Research Center) — the full detail is in the Special populations card below. Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Still wondering about combining Finasteride and Algal Oil? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
How we checked

Why No Interaction Is Listed for Finasteride

Interactions in our licensed database are recorded against drug classes, not just single drug names. Finasteride is filed under 3 classifications — including cytochrome p450 3a4 (cyp3a4) substrates, oral drugs. Algal Oil has documented interactions with 3 drug classes — the most serious being antidiabetes drugs (moderate), antihypertensive drugs (moderate) and anticoagulant/antiplatelet drugs (minor) — and none of Finasteride’s classifications are among them.

Classification data comes from our licensed Natural Medicines dataset. A medication can belong to classes beyond those recorded there, so this describes how the check was run — it is not a safety guarantee.

Keep it in perspective

Algal Oil Does Interact With Other Medications

Algal Oil has 258 moderate, 117 minor known drug interactions in our database — Finasteride isn’t one of them. If you take anything else, check it against the full list below.

Taking anything else?

Check Another of Your Medications Against Algal Oil

Covers the 2,830 medications we’ve checked against Algal Oil. Pick one to open its full report.

What to actually watch for

No Interaction Found — But Data Suggests Algal Oil and Finasteride May Share Several of the Same Side Effects

This is not an interaction. Neither one changes how your body handles the other, and nothing here says they react together. What our sources do show is that each has separately been linked to the effects below — so taking both can make those effects more likely to turn up, and harder to pin on one or the other if they do.

  • Itching / A skin rash Additional detail

    Algal Oil

    “Orally, one parent of a pediatric patient treated with algal oil providing docosahexaenoic acid (DHA) 600 mg daily for 16 weeks reported increased hair loss beginning 6 weeks after completion of supplementation. It is unclear if this adverse effect is specifically related to algal oil intake.”

    Algal Oil · Natural Medicines adverse-effect record, reported in alopecia.

    3 sources cited
    1. 90699. Richardson AJ, Burton JR, Sewell RP, Spreckelsen TF, Montgomery P. Docosahexaenoic acid for reading, cognition and behavior in children aged 7-9 years: a randomized, controlled trial (the DOLAB Study). PLoS One. 2012;7(9):e43909. PubMed
    2. 15497. Yokoyama M, Origasa H, Matsuzaki M, et al. Effects of eicosapentaenoic acid on major coronary events in hypercholesterolaemic patients (JELIS): a randomised open-label, blinded endpoint analysis. Lancet 2007;369:1090-8. PubMed
    3. 48217. Mischoulon D, Best-Popescu C, Laposata M, et al. A double-blind dose-finding pilot study of docosahexaenoic acid (DHA) for major depressive disorder. Eur Neuropsychopharmacol. 2008;18(9):639-645. PubMed

    Finasteride

    Listed in the ADVERSE REACTIONS section of the FDA label for Finasteride. Read the label on DailyMed ›

  • Dizziness Additional detail

    Algal Oil

    “Orally, algal oil may theoretically cause insomnia or light-headedness/dizziness due to its constituent docosahexaenoic acid (DHA). In one clinical study, three adult patients reported light-headedness or dizziness, and one patient reported insomnia, when treated with DHA 2 grams daily. It is unclear if these events are treatment related, as one patient in the placebo group also reported insomnia.”

    Algal Oil · Natural Medicines adverse-effect record, reported in insomnia.

    1 source cited
    1. 10869. Marangell LB, Martinez JM, Zboyan HA, et al. A double-blind, placebo-controlled study of the omega-3 fatty acid docosahexaenoic acid in the treatment of major depression. Am J Psychiatry 2003;160:996-8.. PubMed

    Finasteride

    Listed in the ADVERSE REACTIONS section of the FDA label for Finasteride. Read the label on DailyMed ›

Reported for Algal Oil but not commonly for Finasteride: diarrhea, muscle pain, bloating or gas and joint pain.

Effects for Finasteride come from the ADVERSE REACTIONS section of its FDA label; effects for Algal Oil come from the Natural Medicines adverse-effect record, quoted above. Wording is matched across sources by our own clinical vocabulary, so treat this as a prompt to pay attention, not a diagnosis.

Special populations

Algal Oil in Pregnancy & Breastfeeding

Pregnancy And Lactation Likely Safe

When used orally and appropriately. Docosahexaenoic acid (DHA)-enriched algal oil is commonly included as a component of prenatal vitamins. Algal oil providing DHA 400-600 mg daily during pregnancy has been used with apparent safety in most clinical research. When taken as a prenatal supplement, DHA-enriched algal oil increases DHA levels in breast milk. Taking DHA-enriched algal oil during lactation also increases levels of DHA in breast milk. One study found that using DHA-enriched algal oil during lactation increased the risk of bronchopulmonary dysplasia in breastfed infants born at less than 29 weeks gestational age; however, it is unclear if this was due to DHA or various confounding factors. The tolerable upper intake level of DHA during pregnancy or lactation has not been established. Most experts recommend an intake of DHA 200-300 mg daily during pregnancy and lactation. While it is typically advised that this need be met by consuming 8-12 ounces of seafood weekly during pregnancy and 4-8 ounces weekly during lactation, individuals with nutrient deficiency or those following a vegan diet may meet this need with supplementation, including algal oil. There is insufficient reliable information available about the safety of eicosapentaenoic acid (EPA)-enriched algal oils during pregnancy or lactation.

DISCLAIMER: This tool is intended for informational purposes only, and should not be interpreted as specific medical advice. Patients should consult with a qualified healthcare provider before making decisions about therapies and/or health conditions.© 2026 Therapeutic Research Center

Overlapping uses

What Finasteride Is Prescribed For, and What Algal Oil Has Been Studied For

These two come up together because they touch the same health topic — not because they do the same job. Finasteride is a prescription medicine with approved uses on its FDA label. Algal Oil is a supplement: what follows is what researchers have looked at it for, and how strong that evidence is.

Finasteride is prescribed for: Finasteride tablets (including the brand Proscar) are used in men with an enlarged prostate (benign prostatic hyperplasia, or BPH) to improve urinary symptoms, lower the risk of acute urinary retention (a sudden inability to urinate), and reduce the need for prostate surgery. Finasteride tablets may also be used alongside the alpha-blocker doxazosin to slow the progression of BPH symptoms. Propecia (and finasteride 1 mg coated tablets) is indicated for the treatment of male pattern hair loss (androgenetic alopecia) in men only. Propecia is not approved for use in women, and its effectiveness for hair loss at the temples has not been established.

Read the rest of what Finasteride is prescribed for

Finasteride is not approved for the prevention of prostate cancer.

Algal Oil has been studied for:

  • Cancer studied, not established Algal Oil has been studied for this. Natural Medicines rates the evidence: Insufficient Reliable Evidence To Rate Read what the research shows

    Algal Oil for cancer

    Although there is interest in using oral algal oil for cancer prevention, there is insufficient reliable information about the clinical effects of algal oil for this purpose.

Effectiveness ratings and the research summaries above are the verbatim record from the Natural Medicines database, which grades evidence from “Effective” down to “Insufficient Reliable Evidence To Rate”. A rating below the top of that scale means researchers have looked at it — not that it works, and never that it can stand in for a prescribed medicine. Do not stop or replace Finasteride on your own; if you are taking Algal Oil for the same health topic, tell your prescriber, especially if the medicine is being adjusted to a target.

From our Q&A

Questions About Algal Oil or Finasteride

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Algal Oil or Finasteride, not necessarily both, but if one is close to what you were about to ask it will usually go further than a database entry can:

Not quite your question? Ask our pharmacists directly — it is free, there is no account required, and answers usually come back within 24 hours.

Everything else you take

See Every Supplement That Interacts With Finasteride

This page covers Algal Oil only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Finasteride page lists 138 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Grapefruit (major), St. John's Wort (major), Acacia Rigidula (moderate) and Adrafinil (moderate).

By severity: 3 major · 94 moderate · 41 minor.

From our pharmacist’s overview on the Finasteride page

“The supplement list for finasteride (Propecia, Proscar) is one I would read carefully rather than skim, because three of its 138 entries are rated major. Almost everything here works through the same liver enzyme, CYP3A4, that clears finasteride.”

Reviewed by 2 · Jul 18, 2026

Open the Finasteride interaction page

One more smart check

Taking Algal Oil as Part of a Dietary Supplement Product? Check It for Interactions

We hold 188 real supplement products containing Algal Oil, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Algal Oil. Even though Algal Oil itself has no known interaction with Finasteride, another ingredient on your label might. Find your product and we’ll check every ingredient on its label:

How much people look this up

Where Algal Oil and Finasteride Sit Against Everything Else

Out of every supplement and medication people look up on HelloPharmacist, here is where these two land this week — and which way each has been moving.

Supplement Algal Oil
Top 25%

#308 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Finasteride
Top 5%

#63 of 2,830 medications looked up here in the last 7 days

29 days ago today

Position among everything looked up on this site, not a measure of how commonly either one is used or how important it is. A supplement can climb this list because of a news story. It counts every request to the page, automated ones included, and nothing here identifies anyone.

Where does our data come from?
  • Source: the Natural Medicines (TRC Healthcare) clinical database — the evidence-graded professional reference for herb & supplement interactions.
  • Citation library: 103,510 references behind our interaction content, 65,311 of them resolved to verified PubMed/DOI sources. See every Algal Oil reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 13, 2026. The Algal Oil and Finasteride records this page draws on were last updated July 10, 2026.
  • What “no known interaction” means: no documented interaction in the sources above — not a guarantee of safety. Supplements are studied far less than prescription drugs, so we say exactly what the evidence supports, and nothing more.
Data structure & sourcing designed and verified by .
Supplement

About Algal Oil

What is Algal Oil?

Algal Oil
  • Vegan/vegetarian source of omega-3s (DHA and EPA)
  • Heart and triglyceride health
  • Brain and eye support
  • Pregnancy and infant nutrition
  • General anti-inflammatory support

Algal oil is a plant-based source of the omega-3 fats DHA and (in some products) EPA, making it a popular alternative to fish oil for vegetarians, vegans, and people who dislike fish. There is reasonable evidence that omega-3s can lower triglycerides and support heart and brain health, though more research is needed for many specific uses. It is generally well tolerated, but check with your pharmacist or doctor before starting, especially if you take blood thinners or are pregnant.

Oil extracted from microalgae · Softgel capsules, liquid oil, gummies, fortified foods and infant formula

An interaction check asks whether these two react with each other — it does not ask whether Algal Oil is a good idea for someone in your situation. Here is what our Algal Oil record says about it on its own.

Algal Oil: dosing

There is no single official dose of algal oil, and products vary widely in how much DHA and EPA they contain. The best approach is to follow the directions on the product label and look at the amount of DHA and EPA per serving rather than the total oil amount.Doses are often described by the milligrams of DHA (and sometimes EPA) they provide.

From our Algal Oil monograph — the full record covers uses, side effects and every documented interaction.

Read the full Algal Oil monograph & all interactions
Medication

About Finasteride

What Is Finasteride Used For?

Brand names: Propecia, Proscar

Finasteride tablets (including the brand Proscar) are used in men with an enlarged prostate (benign prostatic hyperplasia, or BPH) to improve urinary symptoms, lower the risk of acute urinary retention (a sudden inability to urinate), and reduce the need for prostate surgery. Finasteride tablets may also be used alongside the alpha-blocker doxazosin to slow the progression of BPH symptoms.

Propecia (and finasteride 1 mg coated tablets) is indicated for the treatment of male pattern hair loss (androgenetic alopecia) in men only. Propecia is not approved for use in women, and its effectiveness for hair loss at the temples has not been established. Finasteride is not approved for the prevention of prostate cancer.

See full Finasteride drug information
Keep checking

Other Drugs & Algal Oil

Browse every other medication we’ve checked against Algal Oil — both the ones with a known interaction and the ones without. Select any drug for the full detail.

0Major
258Moderate
117Minor
2,454No known interaction
Moderate

258 interactions

Showing 60 of 258 moderate interactions — see all 258 on the Algal Oil page.

Minor

117 interactions

Showing 60 of 117 minor interactions — see all 117 on the Algal Oil page.

No interaction 2,454 drugs checked — show the list
Evidence & sources

Algal Oil References

The 43 references that drive our Algal Oil monograph and interaction data, from the evidence-graded Natural Medicines (TRC Healthcare) database. Citations with a link open the study on PubMed or the publisher’s site.

  1. Prisco D, Paniccia R, Bandinelli B, et al. Effect of medium-term supplementation with a moderate dose of n-3 polyunsaturated fatty acids on blood pressure in mild hypertensive patients. Thromb Res 1998;1:105-12.
  2. Grimsgaard S, Bonaa KH, Hansen JB, Nordoy A. Highly purified eicosapentaenoic acid and docosahexaenoic acid in humans have similar triacylglycerol-lowering effects but divergent effects on serum fatty acids. Am J Clin Nutr 1997;66:649-59.
  3. Toft I, Bonaa KH, Ingebretsen OC, et al. Effects of n-3 polyunsaturated fatty acids on glucose homeostasis and blood pressure in essential hypertension. A randomized, controlled trial. Ann Intern Med 1995;123:911-8.
  4. Sacks FM, Hebert P, Appel LJ, et al. Short report: the effect of fish oil on blood pressure and high-density lipoprotein-cholesterol levels in phase I of the trials of hypertension prevention. J Hypertens 1994;12:209-13.
  5. Vandongen R, Mori TA, Burke V, et al. Effects on blood pressure of omega 3 fats in subjects at increased risk of cardiovascular disease. Hypertension 1993;22:371-9. PubMed
  6. FDA. Center for Food Safety and Applied Nutrition. Letter regarding dietary supplement health claim for omega-3 fatty acids and coronary heart disease. Available at: http://www.fda.gov/ohrms/dockets/dockets/95s0316/95s-0316-Rpt0272-38-Appendix-D-Reference
  7. Leaf A. On the reanalysis of the GISSI-Prevenzione. Circulation 2002;105:1874-5. PubMed
  8. Connor WE. n-3 Fatty acids from fish and fish oil: panacea or nostrum? Am J Clin Nutr 2001;74;415-6. PubMed
  9. Calder PC. N-3 polyunsaturated fatty acids, inflammation and immunity: pouring oil on troubled waters or another fishy tale? Nutr Res 2001;21:309-41. DOI
  10. Pedersen HS, Mulvad G, Seidelin KN, et al. N-3 fatty acids as a risk factor for haemorrhagic stroke. Lancet 1999;353:812-3. PubMed
  11. Terano T, Hirai A, Hamazaki T, et al. Effect of oral administration of highly purified eicosapentaenoic acid on platelet function, blood viscosity and red cell deformability in healthy human subjects. Atherosclerosis 1983;46:321-31.. PubMed
  12. Kris-Ehterton PM, Harris WS, Appel LJ, et al. Fish consumption, fish oil, omega-3 fatty acids, and cardiovascular disease. Circulation 2002;106:2747-57. PubMed
  13. Woodman RJ, Mori TA, Burke V, et al. Effects of purified eicosapentaenoic and docosahexaenoic acids on glycemic control, blood pressure, and serum lipids in type 2 diabetic patients with treated hypertension. Am J Clin Nutr 2002;76:1007-15.. PubMed
  14. Marangell LB, Martinez JM, Zboyan HA, et al. A double-blind, placebo-controlled study of the omega-3 fatty acid docosahexaenoic acid in the treatment of major depression. Am J Psychiatry 2003;160:996-8.. PubMed
  15. Leng GC, Smith FB, Fowkes FG, et al. Relationship between plasma essential fatty acids and smoking, serum lipids, blood pressure and haemostatic and rheological factors. Prostaglandins Leukot Essent Fatty Acids 1994;51:101-8. PubMed

Medication overviews come from MedlinePlus (NIH); supplement label data from the NIH Dietary Supplement Label Database. Content is written and reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.

Pharmacist Counseling Corner

Taking Algal Oil and Finasteride Together: Common Questions

Is it safe to take Algal Oil with Finasteride?
We do not list a known interaction between Algal Oil and Finasteride. That does not guarantee the combination is risk-free, so confirm with your pharmacist or doctor — especially if you take other medications or have a health condition.
Do Algal Oil and Finasteride have any of the same side effects?
Yes — our sources link each of them separately to 3 of the same effects. That is not an interaction: neither changes how your body handles the other. It does mean that if one of those effects turns up, it can be harder to tell which one is behind it. They are listed on this page with the source behind each.
Are Algal Oil and Finasteride used for the same thing?
They overlap in purpose, which usually means the real question is whether you need both rather than whether they are safe together. This page lists the shared uses and how strong the evidence is for Algal Oil in each. That is a conversation for your prescriber, especially if Finasteride is being adjusted to a target.
How was the Algal Oil and Finasteride combination checked?
Interactions in our licensed database are recorded against drug classes. Finasteride is filed under 3 classifications, and Algal Oil has documented interactions with 3 drug classes — none of Finasteride's classifications are among them. A medication can belong to classes beyond those recorded in our dataset, so this describes how the check was run rather than guaranteeing safety.
Does Algal Oil interact with any other medications?
Yes. Algal Oil has 375 documented drug interactions in our database — Finasteride is simply not one of them. If you take anything else, it is worth checking each one; they are all listed on this page.
Does Finasteride interact with any supplements?
Yes. Finasteride has documented interactions with 138 supplements in our database — Algal Oil is not one of them. The Finasteride interaction page linked on this page lists every one, ranked by severity.

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

Still Have a Question About Finasteride and Algal Oil?

Our pharmacists answer your medication & supplement questions — free.

Ask a pharmacist

This information is for education only and is not a substitute for professional medical advice. Always check with your pharmacist or doctor before starting, stopping, or combining supplements and medications.