Drug & supplement interaction

Fermented Milk + Finasteride

Finasteride brand names: Propecia, Proscar.

No Known Interaction
Medically reviewed by · Updated July 2026 · Pair last verified Sep 13, 2026
The bottom line No known interaction

We found no known interaction between Fermented Milk 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.

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Interaction report

Fermented Milk 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 Fermented Milk 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.

Fermented Milk safety at a glance

Fermented Milk overall Generally safe Fermented milk is widely consumed as a food and is generally safe for most people.
Pregnancy Use caution Pasteurized fermented milk is generally fine, but avoid unpasteurized (raw-milk) products during pregnancy.
Breastfeeding Generally safe Pasteurized fermented milk is generally considered safe as part of a normal diet while breastfeeding.

Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Still wondering about combining Finasteride and Fermented Milk? 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. Fermented Milk has documented interactions with 3 drug classes — the most serious being antibiotic drugs (moderate), antihypertensive drugs (moderate) and immunosuppressants (moderate) — 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

Fermented Milk Does Interact With Other Medications

Fermented Milk has 474 moderate known drug interactions in our database — Finasteride isn’t one of them. If you take anything else, check it against the full list below.

Moderate 474 No known interaction 2,356 (incl. Finasteride)
Taking anything else?

Check Another of Your Medications Against Fermented Milk

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

What to actually watch for

No Interaction Found — But Data Suggests Fermented Milk 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

    Fermented Milk

    “Orally, pruritus was reported in one patient after consuming fermented milk containing Lactobacillus acidophilus CI1285. Atopic dermatitis was possibly associated with the use of fermented milk in a clinical trial.”

    Fermented Milk · Natural Medicines adverse-effect record, reported in dermatitis.

    2 sources cited
    1. 25494. Beausoleil, M., Fortier, N., Guenette, S., L'ecuyer, A., Savoie, M., Franco, M., Lachaine, J., and Weiss, K. Effect of a fermented milk combining Lactobacillus acidophilus Cl1285 and Lactobacillus casei in the prevention of antibiotic-associated diarrhea:
    2. 96882. Prodeus A, Niborski V, Schrezenmeir J, Gorelov A, Shcherbina A, Rumyantsev A. Fermented milk consumption and common infections in children attending day-care centers: A randomized trial. J Pediatr Gastroenterol Nutr. 2016;63(5):534-543. PubMed

    Finasteride

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

Reported for Fermented Milk but not commonly for Finasteride: stomach pain, constipation, bloating or gas and vomiting.

Effects for Finasteride come from the ADVERSE REACTIONS section of its FDA label; effects for Fermented Milk 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.

From our Q&A

Questions About Fermented Milk 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 Fermented Milk 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 Fermented Milk 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

How much people look this up

Where Fermented Milk 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 Fermented Milk
Top half

#388 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 Fermented Milk reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 13, 2026. The Fermented Milk 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 Fermented Milk

What is Fermented Milk?

  • Digestive health
  • Supporting gut bacteria (probiotics)
  • Lactose-related digestive discomfort
  • General nutrition (protein, calcium)
  • Immune support
  • Diarrhea prevention

Fermented milk is a food made by culturing milk with helpful bacteria or yeast, and it provides protein, calcium, and probiotics. It is generally safe for most people and may help digestion and gut health, though benefits depend on the product and strains used. People with milk allergy or weakened immune systems should be cautious.

Milk fermented by bacteria or yeast cultures · Yogurt, kefir, cultured buttermilk, drinkable yogurt, fermented milk drinks, powders

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

Fermented Milk: dosing

There is no single standard dose for fermented milk. As a food, people commonly have a serving such as a cup of yogurt or kefir, but amounts vary widely.For probiotic products, the helpful microbes are often measured in colony-forming units (CFU), and the right amount depends on the strain and the product.

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

Read the full Fermented Milk 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 & Fermented Milk

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

0Major
474Moderate
0Minor
2,355No known interaction
474 Moderate 2,355 No interaction
Moderate

474 interactions

Showing 60 of 474 moderate interactions — see all 474 on the Fermented Milk page.

No interaction 2,355 drugs checked — show the list

We also checked Fermented Milk against these medications and found no known interaction in our sources. Open any page to confirm.

Showing the 60 most looked-up of 2,355 medications checked with no known interaction — see the full Fermented Milk list.

See the full Fermented Milk interactions page
See every supplement checked against Finasteride, ranked by severity
Evidence & sources

Fermented Milk References

The 16 references that drive our Fermented Milk 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. Pierce A. The American Pharmaceutical Association Practical Guide to Natural Medicines. New York: The Stonesong Press, 1999:19.
  2. Ishikawa H, Akedo I, Umesaki Y, et al. Randomized controlled trial of the effect of bifidobacteria-fermented milk on ulcerative colitis. J Am Coll Nutr 2003;22:56-63. PubMed
  3. Inoue K, Shirai T, Ochiai H, et al. Blood-pressure-lowering effect of a novel fermented milk containing gamma-aminobutyric acid (GABA) in mild hypertensives. Eur J Clin Nutr 2003;57:490-95.
  4. Xiao JZ, Takahashi S, Odamaki T, et al. Antibiotic susceptibility of bifidobacterial strains distributed in the Japanese market. Biosci Biotechnol Biochem. 2010;74(2):336-42. PubMed
  5. Tamura, M., Shikina, T., Morihana, T., Hayama, M., Kajimoto, O., Sakamoto, A., Kajimoto, Y., Watanabe, O., Nonaka, C., Shida, K., and Nanno, M. Effects of probiotics on allergic rhinitis induced by Japanese cedar pollen: randomized double-blind, placebo-c
  6. Beausoleil, M., Fortier, N., Guenette, S., L'ecuyer, A., Savoie, M., Franco, M., Lachaine, J., and Weiss, K. Effect of a fermented milk combining Lactobacillus acidophilus Cl1285 and Lactobacillus casei in the prevention of antibiotic-associated diarrhea:
  7. Aihara, K., Kajimoto, O., Hirata, H., Takahashi, R., and Nakamura, Y. Effect of powdered fermented milk with Lactobacillus helveticus on subjects with high-normal blood pressure or mild hypertension. J Am Coll Nutr 2005;24(4):257-265.
  8. Salminen, E., Elomaa, I., Minkkinen, J., Vapaatalo, H., and Salminen, S. Preservation of intestinal integrity during radiotherapy using live Lactobacillus acidophilus cultures. Clin Radiol 1988;39(4):435-437. PubMed
  9. Turchet, P., Laurenzano, M., Auboiron, S., and Antoine, J. M. Effect of fermented milk containing the probiotic Lactobacillus casei DN-114001 on winter infections in free-living elderly subjects: a randomised, controlled pilot study. J Nutr Health Aging 2
  10. Fukushima, Y., Miyaguchi, S., Yamano, T., Kaburagi, T., Iino, H., Ushida, K., and Sato, K. Improvement of nutritional status and incidence of infection in hospitalised, enterally fed elderly by feeding of fermented milk containing probiotic Lactobacillus
  11. Cobo Sanz, J. M., Mateos, J. A., and Munoz Conejo A. [Effect of Lactobacillus casei on the incidence of infectious conditions in children]. Nutr Hosp 2006;21(4):547-551.
  12. Tormo Carnicer R., Infante Pina D., Rosello Mayans E., and Bartolome Comas R. [Intake of fermented milk containing Lactobacillus casei DN-114 001 and its effect on gut flora]. An Pediatr (Barc) 2006;65(5):448-453.
  13. Rio, M. E., Zago Beatriz L., Garcia, H., and Winter, L. [The nutritional status change the effectiveness of a dietary supplement of lactic bacteria on the emerging of respiratory tract diseases in children]. Arch Latinoam Nutr 2002;52(1):29-34.
  14. Hove KD, Brøns C, Færch K, Lund SS, Rossing P, Vaag A. Effects of 12 weeks of treatment with fermented milk on blood pressure, glucose metabolism and markers of cardiovascular risk in patients with type 2 diabetes: a randomised double-blind placebo-contro
  15. Prodeus A, Niborski V, Schrezenmeir J, Gorelov A, Shcherbina A, Rumyantsev A. Fermented milk consumption and common infections in children attending day-care centers: A randomized trial. J Pediatr Gastroenterol Nutr. 2016;63(5):534-543. 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 Fermented Milk and Finasteride Together: Common Questions

Is it safe to take Fermented Milk with Finasteride?
We do not list a known interaction between Fermented Milk 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 Fermented Milk and Finasteride have any of the same side effects?
Yes — our sources link each of them separately to 2 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.
How was the Fermented Milk and Finasteride combination checked?
Interactions in our licensed database are recorded against drug classes. Finasteride is filed under 3 classifications, and Fermented Milk 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 Fermented Milk interact with any other medications?
Yes. Fermented Milk has 474 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 — Fermented Milk 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

Where next

Keep Exploring

Fermented Milk monograph Uses, safety profile, and every drug interaction in one place Finasteride drug information The full plain-English guide to this medication Finasteride supplement interactions Every supplement checked against Finasteride, ranked by severity Supplement interaction checker Check any supplement or product against your medications Browse medications A–Z Every drug we’ve checked against herbs & supplements References The 16 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Finasteride and Fermented Milk?

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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.