Evidence-based·Last reviewed June 1, 2026·How we grade evidence

Calcium Folinate

Q: Is calcium folinate the same as 5-MTHF?

Both are reduced folates that bypass DHFR, but they are different molecules. Folinic acid is 5-formyltetrahydrofolate; 5-MTHF is 5-methyltetrahydrofolate.

VitaminBest with a meal

Prescription folate (calcium salt of folinic acid / leucovorin) — same molecule under two names. FDA-approved for methotrexate rescue, colorectal cancer adjunct with 5-FU, and folate-deficient megaloblastic anemia. Emerging RCT evidence for autistic children with folate receptor alpha autoantibodies; AAP says not yet routine.

Prescription medication — not a dietary supplement

This is an FDA-approved (or investigational) drug, not a supplement. It requires a prescription and medical supervision. The information below summarizes clinical-trial evidence for education only — it is not a recommendation to obtain or use it without a doctor.

Quick decision guide

May help most

Cancer patients on methotrexate or 5-fluorouracil regimens, under oncology supervision. Selected pediatric autism cases under specialist guidance.

Common dosing range

Methotrexate rescue: 15 mg q6h × 10 doses. Colorectal: 20–200 mg/m² IV per protocol. Megaloblastic anemia: 1 mg/day IM.

When to expect effects

Hours to days for rescue / anemia; weeks-to-months in autism trials.

Watch out for

Can mask vitamin B12 deficiency anemia while neurologic damage from B12 deficiency progresses unchecked. Always confirm B12 status before chronic use.

Evidence snapshot

Methotrexate rescue (oncology / RA)Strong

5-FU potentiation in colorectal cancerStrong

Folate-deficient megaloblastic anemiaStrong

Autism (FRAA-positive children)Emerging

What is it

Calcium folinate (folinic acid, leucovorin, 5-formyltetrahydrofolate calcium salt) is a reduced folate metabolite used clinically as leucovorin rescue after methotrexate and as a bioavailable folate supplement.

Is it worth it for you?

Use this as a quick fit check, not a diagnosis.

Worth considering if…

Your oncologist prescribed it as part of methotrexate rescue or a colorectal cancer (5-FU based) regimen

You have megaloblastic anemia from folate deficiency and can't take oral folate

Your rheumatologist prescribed it alongside methotrexate to mitigate side effects

Your pediatrician/specialist has documented folate receptor alpha autoantibodies and is trialing it for an autistic child

Probably skip if…

You're a healthy adult looking for a folate supplement — use food sources or standard folate / methylfolate

You're hoping to self-administer for autism without a specialist — AAP recommends against routine use

You have vitamin B12 deficiency that hasn't been ruled out — folinic acid can mask the anemia while nerve damage worsens

You're using it 'because it sounds better than folic acid' — for healthy adults, folate from food or standard folic acid/methylfolate is appropriate

Evidence at a glance

Goal	Effect	Best fit	Time
Methotrexate rescue (high-dose methotrexate therapy) Strong Evidence	Restores tetrahydrofolate pools and rescues bone marrow and GI mucosa from methotrexate toxicity	Patients receiving high-dose methotrexate (oncology, certain autoimmune conditions)	Hours (each dose)
Colorectal cancer (potentiation of 5-fluorouracil) Strong Evidence	Significantly improved tumor response and survival vs 5-FU alone; foundation of modern colorectal regimens	Patients with colorectal cancer prescribed 5-FU-based chemotherapy	Cumulative over the chemotherapy course
Megaloblastic anemia from folate deficiency Strong Evidence	Rapid hematologic recovery in folate-deficient megaloblastic anemia	Patients with folate-deficient megaloblastic anemia who cannot take oral folate	Days to weeks for hematologic response
Autism spectrum disorder with folate receptor alpha autoantibodies (FRAA) Limited Evidence	Significant verbal communication improvement in FRAA-positive children; effect smaller in FRAA-negative children	Autistic children with documented folate receptor alpha autoantibodies, under specialist supervision	Weeks to months (12-week trial endpoint)

Methotrexate rescue (high-dose methotrexate therapy)

Strong Evidence

Effect: Restores tetrahydrofolate pools and rescues bone marrow and GI mucosa from methotrexate toxicity
Best fit: Patients receiving high-dose methotrexate (oncology, certain autoimmune conditions)
Time: Hours (each dose)

Colorectal cancer (potentiation of 5-fluorouracil)

Strong Evidence

Effect: Significantly improved tumor response and survival vs 5-FU alone; foundation of modern colorectal regimens
Best fit: Patients with colorectal cancer prescribed 5-FU-based chemotherapy
Time: Cumulative over the chemotherapy course

Megaloblastic anemia from folate deficiency

Strong Evidence

Effect: Rapid hematologic recovery in folate-deficient megaloblastic anemia
Best fit: Patients with folate-deficient megaloblastic anemia who cannot take oral folate
Time: Days to weeks for hematologic response

Autism spectrum disorder with folate receptor alpha autoantibodies (FRAA)

Limited Evidence

Effect: Significant verbal communication improvement in FRAA-positive children; effect smaller in FRAA-negative children
Best fit: Autistic children with documented folate receptor alpha autoantibodies, under specialist supervision
Time: Weeks to months (12-week trial endpoint)

Evidence for 4 uses

AI-assisted evidence assessment — talk to your doctor before relying on any single supplement.

Methotrexate rescue (high-dose methotrexate therapy)

Corrects deficiency

Strong Evidence

Standard of care after high-dose methotrexate for osteosarcoma and other malignancies. Leucovorin bypasses methotrexate's blockade of dihydrofolate reductase, allowing normal cells to resume DNA synthesis. Standard adult dose: 15 mg PO/IM/IV every 6 hours for 10 doses, starting 24 hours after methotrexate infusion. Also used to rescue from accidental folate-antagonist overdose.

Effect size

Restores tetrahydrofolate pools and rescues bone marrow and GI mucosa from methotrexate toxicity

Time to effect

Hours (each dose)

Best fit

Patients receiving high-dose methotrexate (oncology, certain autoimmune conditions)

Less likely

Anyone not actually receiving a folate antagonist

Bottom line: Standard, life-saving use in methotrexate-based chemotherapy — nothing else replaces it.

SourceFDA leucovorin calcium prescribing information — FDA AccessData Patel & Sharma, 2024 — StatPearls (NCBI Bookshelf)

Colorectal cancer (potentiation of 5-fluorouracil)

Disease adjunct

Strong Evidence

Standard adjuvant therapy for stage III and advanced colorectal cancer (the FOLFOX, FOLFIRI, and 5-FU/LV regimens). Leucovorin stabilizes the 5-FU–thymidylate synthase complex, enhancing tumor cell kill. Decades of RCT and meta-analytic evidence support this combination for improved disease-free and overall survival.

Effect size

Significantly improved tumor response and survival vs 5-FU alone; foundation of modern colorectal regimens

Time to effect

Cumulative over the chemotherapy course

Best fit

Patients with colorectal cancer prescribed 5-FU-based chemotherapy

Less likely

Not applicable outside oncology indication

Bottom line: Cornerstone of colorectal cancer chemotherapy — used universally with 5-FU.

SourceFDA leucovorin calcium prescribing information — FDA AccessData National Cancer Institute — Leucovorin Calcium — NCI Drugs.gov

Megaloblastic anemia from folate deficiency

Corrects deficiency

Strong Evidence

Approved for IV/IM treatment of megaloblastic anemia due to folate deficiency when oral folate therapy is not feasible. Most patients can take oral folate instead; injectable leucovorin is reserved for severe cases or malabsorption. Critical: rule out B12 deficiency first — folinic acid can mask B12-deficiency anemia while neurologic damage from B12 deficiency progresses.

Effect size

Rapid hematologic recovery in folate-deficient megaloblastic anemia

Time to effect

Days to weeks for hematologic response

Best fit

Patients with folate-deficient megaloblastic anemia who cannot take oral folate

Less likely

Mild folate deficiency easily corrected with food or oral folate / folic acid

Bottom line: Standard parenteral folate for severe cases; otherwise oral folate is simpler and cheaper.

SourceFDA leucovorin calcium prescribing information — FDA AccessData Patel & Sharma, 2024 — StatPearls (NCBI Bookshelf)

Autism spectrum disorder with folate receptor alpha autoantibodies (FRAA)

Disease adjunct

Limited Evidence

Frye 2018 (Molecular Psychiatry) reported a randomized double-blind placebo-controlled trial of folinic acid (2 mg/kg/day, max 50 mg) in 48 children with ASD and language impairment. Significant improvement in verbal communication, particularly in FRAA-positive children (~77% responders) vs placebo. Two smaller international trials report similar findings, and a 2021 Rossignol/Frye meta-analysis pools the evidence favorably. The American Academy of Pediatrics (2025 FAQ) notes evidence is still insufficient for routine clinical recommendation; use should be in research contexts or specialist-supervised cases with documented FRAA positivity.

Effect size

Significant verbal communication improvement in FRAA-positive children; effect smaller in FRAA-negative children

Time to effect

Weeks to months (12-week trial endpoint)

Best fit

Autistic children with documented folate receptor alpha autoantibodies, under specialist supervision

Less likely

Autistic adults or children without FRAA testing — evidence is in pediatric FRAA-positive subgroup

Bottom line: An emerging area with real RCT signal — but evidence base is still small. Pursue only with a specialist and ideally with FRAA testing.

Evidence is mixed

Findings are promising but mostly from one research group (Frye); independent replication is limited. AAP and other professional bodies have not endorsed routine use.

SourceAAP — Leucovorin Use in Autism FAQ — American Academy of Pediatrics· conflicting

SourceFrye et al., 2018 — Molecular Psychiatry Rossignol & Frye, 2021 — PMC — Journal of Personalized Medicine AAP — Leucovorin Use in Autism FAQ — American Academy of Pediatrics

How it works

Folinic acid is rapidly converted in the body to 5-methyltetrahydrofolate and other active folate cofactors, supporting DNA synthesis, methylation, and homocysteine recycling. Unlike folic acid, it bypasses dihydrofolate reductase, making it useful for methotrexate rescue and for people with MTHFR variants. Leucovorin (calcium folinate) is the standard rescue agent given after high-dose methotrexate to protect normal cells. It is also used with 5-fluorouracil to enhance efficacy in colorectal cancer.

How to take it

1. Typical dose

• Methotrexate rescue (adult): 15 mg PO/IM/IV every 6 hours × 10 doses, starting 24 h after methotrexate • Colorectal cancer (with 5-FU): 20–200 mg/m² IV per protocol • Megaloblastic anemia: 1 mg/day IM • Autism (investigational, FRAA-positive children): 2 mg/kg/day PO, max 50 mg/day, divided

2. Higher studied dose

Up to 200 mg/m² IV in colorectal cancer protocols. Oncology dosing is highly protocol-specific and must come from the prescriber.

3. Timing

Methotrexate rescue is time-critical (starts exactly 24 h after MTX). Otherwise per prescribing physician's schedule.

4. With food

Oral leucovorin can be taken with or without food.

5. Split dosing

Methotrexate rescue requires the q6h dosing schedule. Autism trial protocols typically split daily dose into two.

6. How long to try

Methotrexate rescue: 10 doses (60 hours). Cancer therapy: per protocol cycle. Autism trials: 12 weeks minimum.

What to track

Methotrexate level (oncology) — leucovorin continues until MTX < 0.01 µM

CBC and reticulocyte count (megaloblastic anemia treatment)

B12 level — must be confirmed adequate before chronic folate therapy

Symptoms scales for autism if used in that context

Bottom line: Prescription-only. Dosing is indication-specific and must come from the prescriber, not the supplement aisle.

4 commercial forms

Compare the main delivery options and what they’re best suited for.

Leucovorin calcium tablets (oral)

Oral rescue dose

5, 10, 15, or 25 mg tablets. Used for methotrexate rescue when IV is not needed, and for outpatient autism trials. Well absorbed orally up to ~25 mg per dose.

Oral absorption saturates above ~25 mg/dose — higher doses are given IV.

Leucovorin calcium injection

Inpatient / oncology

50–500 mg vials for IV or IM administration in oncology protocols (high-dose MTX rescue, 5-FU regimens) and severe folate-deficient megaloblastic anemia.

Required for doses above ~25 mg/dose and when oral route is impossible.

Calcium folinate (international name)

Same molecule

Outside the US, the same compound is more often labeled 'calcium folinate.' Identical pharmacology to leucovorin calcium. Different brand names by country.

Identical to leucovorin calcium.

Levoleucovorin (levo-isomer)

Refined isomer

The pharmacologically active L-isomer of leucovorin (sold as Fusilev / Khapzory). Equally effective at about half the dose because the D-isomer in racemic leucovorin is inactive. More expensive; used in some oncology protocols.

Same clinical effect at half the dose of racemic leucovorin.

Safety

Know the common side effects, key cautions, and who should avoid it.

Common side effects

nauseavomitingdiarrhea (especially when combined with 5-FU)occasional rashrare anaphylactoid reactions

Serious risks

Can mask vitamin B12 deficiency anemia — the hematologic anemia resolves while neurologic damage from B12 deficiency progresses unchecked. Always rule out B12 deficiency before chronic folate therapy.
SourcePatel & Sharma, 2024 — StatPearls (NCBI Bookshelf)
Greatly increases 5-FU toxicity — diarrhea, mucositis, neutropenia. Dose reduction of 5-FU is required when combined with leucovorin. Elderly and frail patients particularly vulnerable.
SourceFDA leucovorin calcium prescribing information — FDA AccessData
Rare hypersensitivity / anaphylactoid reactions with IV administration.
SourceFDA leucovorin calcium prescribing information — FDA AccessData

Who should avoid it

Patients with pernicious anemia or other vitamin B12-deficient megaloblastic anemia — folinic acid can mask the diagnosis while neurologic damage progresses.
SourceFDA leucovorin calcium prescribing information — FDA AccessData
Anyone using it for cancer protocols without oncology supervision — dosing is highly individualized.
SourceFDA leucovorin calcium prescribing information — FDA AccessData
People with known hypersensitivity to folinic acid or its excipients.
SourceFDA leucovorin calcium prescribing information — FDA AccessData

Pregnancy & breastfeeding

Folinic acid is a reduced folate that supports normal fetal development. It is considered safe and is sometimes preferred in women with MTHFR variants or who don't tolerate folic acid. However, in oncology contexts (5-FU combination), the chemotherapy itself is contraindicated in pregnancy, not the leucovorin. Discuss with your obstetrician for any non-standard use.

SourcePatel & Sharma, 2024 — StatPearls (NCBI Bookshelf)

Bottom line: Safe and life-saving in its approved indications when used as prescribed. Self-administration outside those indications carries real risks — mainly masking of B12 deficiency.

Interactions

methotrexateMajor

Designed interaction: leucovorin reverses methotrexate's antifolate effect. In high-dose chemotherapy, this is therapeutic 'rescue.' In low-dose methotrexate for rheumatoid arthritis or psoriasis, inappropriate timing of leucovorin can reduce methotrexate's intended efficacy — always follow the prescriber's schedule precisely.

SourceFDA leucovorin calcium prescribing information — FDA AccessData

5-fluorouracil (5-FU) and capecitabineMajor

Therapeutic combination (boosts tumor kill) but also potentiates toxicity — diarrhea, mucositis, neutropenia. 5-FU dose is reduced when combined with leucovorin per oncology protocols.

SourceFDA leucovorin calcium prescribing information — FDA AccessData

trimethoprim-sulfamethoxazole (Bactrim)Moderate

TMP-SMX is a folate antagonist; in patients on long-term TMP-SMX (e.g., for PCP prophylaxis), leucovorin can rescue from bone marrow suppression — but it can also reduce the antimicrobial efficacy. Use only when clinically indicated.

SourceFDA leucovorin calcium prescribing information — FDA AccessData

phenytoin / phenobarbital / primidone (anticonvulsants)Moderate

Folates (including folinic acid) can lower serum levels of these anticonvulsants and may increase seizure frequency. Monitor anticonvulsant levels closely if starting chronic folinic acid.

SourceFDA leucovorin calcium prescribing information — FDA AccessData

vitamin B12 (cyanocobalamin)Moderate

Functional interaction: folinic acid can correct megaloblastic anemia caused by B12 deficiency, but does not correct the underlying neurologic damage. Always check B12 status before starting chronic folinic acid.

SourcePatel & Sharma, 2024 — StatPearls (NCBI Bookshelf)

Food sources

Food	Amount	%DV
Note: calcium folinate is a prescription drug, not a food	Dietary folate sources include leafy greens, legumes, fortified grains, and liver — see folate / vitamin B9 page	—
Beef liver, cooked	3 oz (~215 mcg DFE folate)	54%
Spinach, boiled	½ cup (~131 mcg DFE)	33%
Black-eyed peas, boiled	½ cup (~105 mcg DFE)	26%
Fortified breakfast cereal	1 serving (~400 mcg DFE)	100%

Note: calcium folinate is a prescription drug, not a food

Amount: Dietary folate sources include leafy greens, legumes, fortified grains, and liver — see folate / vitamin B9 page
%DV: —

Beef liver, cooked

Amount: 3 oz (~215 mcg DFE folate)
%DV: 54%

Spinach, boiled

Amount: ½ cup (~131 mcg DFE)
%DV: 33%

Black-eyed peas, boiled

Amount: ½ cup (~105 mcg DFE)
%DV: 26%

Fortified breakfast cereal

Amount: 1 serving (~400 mcg DFE)
%DV: 100%

Choosing a product

What to look for on the label — and what to be skeptical of.

Look for…

Prescription-only — sourced from a licensed pharmacy with a clinician's order

Brand names include Leucovorin Calcium, Wellcovorin (historic), and generic 'leucovorin calcium' or 'calcium folinate'

Strength clearly labeled in mg of leucovorin (5, 10, 15, 25 mg oral tablets; injectable 50–500 mg vials)

If a specialist is trialing it for autism, prescription should come from a pediatric specialist familiar with the literature

Be skeptical of…

Over-the-counter 'folinic acid' supplements marketed at standard folate-supplementation doses — for healthy adults, simple folate / methylfolate is appropriate and cheaper

Online 'autism cure' claims — leucovorin is investigational; treatment should be specialist-supervised

Combination products marketing 'folinic acid' as a premium folate without clinical context

Any product encouraging use to mask 'low energy' or fatigue without ruling out B12 deficiency first

Frequently asked questions

Is calcium folinate the same as 5-MTHF?⌄

Both are reduced folates that bypass DHFR, but they are different molecules. Folinic acid is 5-formyltetrahydrofolate; 5-MTHF is 5-methyltetrahydrofolate.

References by claim

Methotrexate rescue (high-dose methotrexate therapy)

FDA leucovorin calcium prescribing information — FDA AccessData (2012) link

Patel & Sharma, 2024 — StatPearls (NCBI Bookshelf) (2024) link

Autism spectrum disorder with folate receptor alpha autoantibodies (FRAA)

Frye et al., 2018 — Molecular Psychiatry (2018) link

Rossignol & Frye, 2021 — PMC — Journal of Personalized Medicine (2021) link

AAP — Leucovorin Use in Autism FAQ — American Academy of Pediatrics (2025) link

Colorectal cancer (potentiation of 5-fluorouracil)

National Cancer Institute — Leucovorin Calcium — NCI Drugs.gov (2024) link

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Evidence-based·Last reviewed Jun 1, 2026·Evidence current as of Jun 1, 2026·How we grade evidence

Disclaimer: This page summarizes published clinical-trial data for educational purposes and is not medical advice or a recommendation to use this prescription medication. Dosing, eligibility, and monitoring must be decided by a licensed prescriber.