Drug & supplement interaction

Lactic Acid + Methotrexate

Methotrexate brand names: Rheumatrex, Otrexup, Rasuvo, Reditrex.

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 Lactic Acid and Methotrexate 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

Lactic Acid and Methotrexate

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 Methotrexate and Lactic Acid 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.

Worth understanding: our licensed dataset holds no drug-interaction record for Lactic Acid at all — not against Methotrexate, and not against any other medication we track. This verdict therefore rests on the absence of any recorded data, not on research that looked at this combination and found nothing. We cannot rule an interaction out.

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.

Lactic Acid safety at a glance

Lactic Acid overall Use caution Generally safe in foods and skin products, but strong concentrations can irritate skin and mucous membranes.
Pregnancy Likely Safe When used topically in appropriate concentrations . There is insufficient reliable information available about the safety of lactic acid when used orally during... Read the full pregnancy detail
Breastfeeding Likely Safe When used topically in appropriate concentrations . There is insufficient reliable information available about the safety of lactic acid when used orally during... 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 Methotrexate and Lactic Acid? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
What to actually watch for

No Interaction Found — But Data Suggests Lactic Acid and Methotrexate 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. One of them is worth acting on rather than waiting out — marked below.

  • Bleeding or bruising Worth acting on Additional detail

    Lactic Acid

    “Topically, lactic acid is generally well tolerated when used in concentrations at or below 10% and applied to the face or 15% and applied elsewhere. In general, products should be tested on a small area of skin before applying it to a larger area.

    Alpha hydroxy acids like lactic acid can increase sensitivity to the sun and ultraviolet (UV) light.”

    Lactic Acid · Natural Medicines adverse-effect record, reported in burns.

    6 sources cited
    1. 949. Kempers S, Katz HI, Wildnauer R, Green B. An evaluation of the effect of an alpha hydroxy acid-blend skin cream in the cosmetic improvement of symptoms of moderate to severe xerosis, epidermolytic hyperkeratosis, and ichthyosis. Cutis 1998;61:347-50.
    2. 952. Stiller MJ, Bartolone J, Stern R, et al. Topical 8% glycolic acid and 8% L-lactic acid creams for the treatment of photodamaged skin. A double-blind, vehicle-controlled clinical trial. Arch Dermatol 1996;132:631-6.
    3. 955. Wehr R, Krochmal L, Bagatell F, Ragsdale W. A controlled two-center study of lactate 12 percent lotion and a petrolatum-based creme in patients with xerosis. Cutis 1986;37:205-7, 209.
    4. 106592. Rogers RS 3rd, Callen J, Wehr R, Krochmal L. Comparative efficacy of 12% ammonium lactate lotion and 5% lactic acid lotion in the treatment of moderate to severe xerosis. J Am Acad Dermatol 1989;21(4 Pt 1):714-6. PubMed
    5. 106593. Jennings MB, Logan L, Alfieri DM, Ross CF, Goodwin S, Lesczczynski C. A comparative study of lactic acid 10% and ammonium lactate 12% lotion in the treatment of foot xerosis. J Am Podiatr Med Assoc 2002;92(3):143-8. PubMed
    6. 106594. Dahl MV, Dahl AC. 12% lactate lotion for the treatment of xerosis. A double-blind clinical evaluation. Arch Dermatol 1983;119(1):27-30. DOI

    Methotrexate

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

  • Sun sensitivity Additional detail

    Lactic Acid

    Recorded for Lactic Acid in the same Natural Medicines adverse-effect record shown under Bleeding or bruising above.

    Methotrexate

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

  • Itching Additional detail

    Lactic Acid

    Recorded for Lactic Acid in the same Natural Medicines adverse-effect record shown under Bleeding or bruising above.

    Methotrexate

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

  • A skin rash Additional detail

    Lactic Acid

    Recorded for Lactic Acid in the same Natural Medicines adverse-effect record shown under Bleeding or bruising above.

    Methotrexate

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

Reported for Lactic Acid but not commonly for Methotrexate: numbness or tingling and swelling.

Effects for Methotrexate come from the ADVERSE REACTIONS section of its FDA label; effects for Lactic Acid come from the Natural Medicines adverse-effect record, quoted above. Where a percentage is shown, it is the share of 489,806 voluntary FDA FAERS reports for Methotrexate that mention that effect — a reporting proportion, not an incidence rate and not evidence the drug caused it. Wording is matched across sources by our own clinical vocabulary, so treat this as a prompt to pay attention, not a diagnosis.

Special populations

Lactic Acid in Pregnancy & Breastfeeding

Pregnancy And Lactation Likely Safe

When used topically in appropriate concentrations . There is insufficient reliable information available about the safety of lactic acid when used orally during pregnancy and lactation; avoid using.

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

From our Q&A

Questions About Lactic Acid or Methotrexate

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Lactic Acid or Methotrexate, 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 Methotrexate

This page covers Lactic Acid only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Methotrexate page lists 82 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Apple (major), Beer (major), Grapefruit (major) and Siberian Cocklebur (major).

By severity: 7 major · 60 moderate · 15 minor.

From our pharmacist’s overview on the Methotrexate page

“The liver is where methotrexate and supplements clash most. Methotrexate (Rheumatrex, Otrexup, Rasuvo), used for rheumatoid arthritis, psoriasis, and certain cancers, can strain the liver on its own, and 38 of the 82 interacting ingredients on this list add liver risk of their own, alcohol included, which makes this a list to approach…”

Reviewed by 2 · Jul 18, 2026

Open the Methotrexate interaction page

One more smart check

Taking Lactic Acid as Part of a Dietary Supplement Product? Check It for Interactions

We hold 22 real supplement products containing Lactic Acid, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Lactic Acid. Even though Lactic Acid itself has no known interaction with Methotrexate, 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 Lactic Acid and Methotrexate 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 Lactic Acid
Steady interest

#1,233 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Methotrexate
Top 5%

#49 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 Lactic Acid reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 13, 2026. The Lactic Acid and Methotrexate 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 Lactic Acid

What is Lactic Acid?

  • Skin exfoliation and anti-aging
  • Moisturizing dry skin
  • Maintaining vaginal pH
  • Acne and skin texture
  • Ingredient in fermented foods

Lactic acid is a naturally occurring acid made by the body during exercise and by bacteria that ferment milk and other foods. It is most often used on the skin as an exfoliant and moisturizer and in some vaginal products to support normal pH. While topical skin uses are well established, evidence for swallowing lactic acid supplements for health benefits is limited, so check with a pharmacist before using it.

Topical creams and lotions, chemical peels, oral capsules, foods (fermented dairy), suppositories, mouth rinses

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

Lactic Acid: dosing

There is no single standard dose of lactic acid, because it is used in so many different ways. Skin products commonly contain a range of concentrations, and professional peels use stronger amounts applied by trained providers.For any product, the best approach is to follow the label directions and start slowly to see how your skin reacts.

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

Read the full Lactic Acid monograph & all interactions
Medication

About Methotrexate

What Is Methotrexate Used For?

Brand names: Rheumatrex, Otrexup, Rasuvo, Reditrex

Methotrexate treats a wide range of serious conditions. In cancer care, it is used for acute lymphoblastic leukemia, non-Hodgkin lymphoma, osteosarcoma, breast cancer, head and neck cancer, and gestational trophoblastic neoplasia (a rare tumor related to pregnancy). It is also used to prevent and treat meningeal leukemia (cancer affecting the lining of the brain and spinal cord).

Outside of cancer, methotrexate is prescribed for adults with rheumatoid arthritis (RA), children with polyarticular juvenile idiopathic arthritis (a form of childhood arthritis), and adults with severe psoriasis that hasn't responded well to other treatments.

Most-Reported Side Effects for Methotrexate

From FAERS, the FDA’s public side-effect reporting system (489,806 reports, all brands). Reports are voluntary and are not proof the drug caused the effect.

Rheumatoid arthritis 42,798 reports
Arthralgia 40,830 reports
Fatigue 33,049 reports
Nausea 28,999 reports
Joint swelling 25,026 reports
See full Methotrexate drug information
Keep checking

Other Drugs & Lactic Acid

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

0Major
0Moderate
0Minor
2,829No known interaction
2,829 No interaction
No interaction 2,829 drugs checked — show the list

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

Showing the 60 most looked-up of 2,829 medications checked with no known interaction — see the full Lactic Acid list.

See the full Lactic Acid interactions page
See every supplement checked against Methotrexate, ranked by severity
Evidence & sources

Lactic Acid References

The 21 references that drive our Lactic Acid 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. Kempers S, Katz HI, Wildnauer R, Green B. An evaluation of the effect of an alpha hydroxy acid-blend skin cream in the cosmetic improvement of symptoms of moderate to severe xerosis, epidermolytic hyperkeratosis, and ichthyosis. Cutis 1998;61:347-50.
  2. Stiller MJ, Bartolone J, Stern R, et al. Topical 8% glycolic acid and 8% L-lactic acid creams for the treatment of photodamaged skin. A double-blind, vehicle-controlled clinical trial. Arch Dermatol 1996;132:631-6.
  3. Wehr R, Krochmal L, Bagatell F, Ragsdale W. A controlled two-center study of lactate 12 percent lotion and a petrolatum-based creme in patients with xerosis. Cutis 1986;37:205-7, 209.
  4. Kurtzweil P. Alpha-hydroxy acids for skin care: Smooth sailing or rough seas? FDA 1999. Available at: /www.fda.gov/fdac/features/1998/298_ahas.html (Accessed 18 August 2000). DOI
  5. Emtestam L, Svensson Å, Rensfeldt K. Treatment of seborrhoeic dermatitis of the scalp with a topical solution of urea, lactic acid, and propylene glycol (K301): results of two double-blind, randomised, placebo-controlled studies. Mycoses. 2012 Sep;55(5):3 PubMed
  6. Köse O, Özmen I, Arca E. An open, comparative study of 10% potassium hydroxide solution versus salicylic and lactic acid combination in the treatment of molluscum contagiosum in children. J Dermatolog Treat. 2013 Aug;24(4):300-4. PubMed
  7. Rogers RS 3rd, Callen J, Wehr R, Krochmal L. Comparative efficacy of 12% ammonium lactate lotion and 5% lactic acid lotion in the treatment of moderate to severe xerosis. J Am Acad Dermatol 1989;21(4 Pt 1):714-6. PubMed
  8. Jennings MB, Logan L, Alfieri DM, Ross CF, Goodwin S, Lesczczynski C. A comparative study of lactic acid 10% and ammonium lactate 12% lotion in the treatment of foot xerosis. J Am Podiatr Med Assoc 2002;92(3):143-8. PubMed
  9. Dahl MV, Dahl AC. 12% lactate lotion for the treatment of xerosis. A double-blind clinical evaluation. Arch Dermatol 1983;119(1):27-30. DOI
  10. Pham HT, Exelbert L, Segal-Owens AC, Veves A. A prospective, randomized, controlled double-blind study of a moisturizer for xerosis of the feet in patients with diabetes. Ostomy Wound Manage 2002;48(5):30-6.
  11. Draelos ZD, Hall S, Munsick C. A 14-day Controlled Study Assessing Qualitative Improvement with 15% Lactic Acid and Ceramides in Skin Moisturization and Desquamation. J Clin Aesthet Dermatol 2020;13(8):E54-E58.
  12. Jennings MB, Alfieri D, Ward K, Lesczczynski C. Comparison of salicylic acid and urea versus ammonium lactate for the treatment of foot xerosis. A randomized, double-blind, clinical study. J Am Podiatr Med Assoc 1998;88(7):332-6. PubMed
  13. Ademola J, Frazier C, Kim SJ, Theaux C, Saudez X. Clinical evaluation of 40% urea and 12% ammonium lactate in the treatment of xerosis. Am J Clin Dermatol 2002;3(3):217-22. PubMed
  14. Jennings MB, Alfieri DM, Parker ER, Jackman L, Goodwin S, Lesczczynski C. A double-blind clinical trial comparing the efficacy and safety of pure lanolin versus ammonium lactate 12% cream for the treatment of moderate to severe foot xerosis. Cutis 2003;71
  15. Uy JJ, Joyce AM, Nelson JP, West B, Montague JR. Ammonium lactate 12% lotion versus a liposome-based moisturizing lotion for plantar xerosis. A double-blind comparison study. J Am Podiatr Med Assoc 1999;89(10):502-5. 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 Lactic Acid and Methotrexate Together: Common Questions

Is it safe to take Lactic Acid with Methotrexate?
We do not list a known interaction between Lactic Acid and Methotrexate. 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 Lactic Acid and Methotrexate have any of the same side effects?
Yes — our sources link each of them separately to 4 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.
Does Methotrexate interact with any supplements?
Yes. Methotrexate has documented interactions with 82 supplements in our database — Lactic Acid is not one of them. The Methotrexate 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

Lactic Acid monograph Uses, safety profile, and every drug interaction in one place Methotrexate drug information The full plain-English guide to this medication Methotrexate supplement interactions Every supplement checked against Methotrexate, 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 21 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Methotrexate and Lactic Acid?

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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.