Peptide Profile
Bestatin (Ubenimex)
Natural dipeptide analogue aminopeptidase inhibitor with dual immunostimulatory and antitumor activity, approved in Japan as adjuvant cancer therapy
Dose Range
10-100mg
Frequency
Once daily
Route
Oral (capsule)
Cycle Length
12+ weeks
Onset
Moderate (1-2 weeks)
Evidence
Moderate
Compound Profile
Scientific & Efficacy Data
C16H24N2O4
Molecular Formula
308.37 g/mol
Molecular Weight
Approximately 2-3 hours (oral administration)
Half-Life
Well absorbed orally; peak plasma concentration reached within 1-2 hours
Bioavailability
58970-76-6
CAS #
72172
PubChem ID ↗
Developed By · 1976
Hamao Umezawa
Institute of Microbial Chemistry, Tokyo / Nippon Kayaku Co., Ltd.
Primary Benefits
Bestatin is a well-characterized immunostimulant that activates T-lymphocytes, macrophages, and natural killer cells while enhancing IL-1 and IL-2 production. Approved in Japan as an adjunctive immunotherapy for acute non-lymphocytic leukemia, it has decades of clinical evidence supporting its immune-enhancing properties.
By stimulating bone marrow stem cell proliferation and enhancing immune recovery after chemotherapy, bestatin supports the body's regenerative processes during cancer treatment. Clinical trials have demonstrated improved survival times in AML patients who achieve complete remission.
Bestatin's ability to enhance immune surveillance and modulate inflammatory pathways through LTA4 hydrolase inhibition has potential implications for age-related immune decline and chronic inflammatory conditions, though direct anti-aging research is limited.
Amino Acid Sequence
(2S,3R)-3-Amino-2-hydroxy-4-phenylbutanoyl-Leucine (dipeptide analogue)Dosing
How much
do I take?
Starting Dose
10-20 mg once daily
Start at the lower end to assess tolerance. Bestatin is well-tolerated orally, but beginning at 10-20 mg allows monitoring for gastrointestinal tolerance and any allergic reactions before increasing to the standard therapeutic dose. Take in the morning with or without food.
Standard Dose
30 mg once daily
The 30 mg once-daily dose is the standard therapeutic regimen used in Japanese clinical practice for leukemia maintenance. This dose has been validated in Phase 1 trials as providing optimal immunostimulatory effects with minimal side effects. Clinical trials in Japan demonstrated significant survival benefits at this dose when used after chemotherapy-induced complete remission in AML patients.
Advanced Dose
60-100 mg once daily
Higher doses of 60-100 mg daily have been explored in clinical trials, particularly for non-oncology indications such as pulmonary arterial hypertension. Phase 1 studies estimated the clinical optimal dose range as 10-100 mg daily. Higher doses should only be used under direct medical supervision, with monitoring of liver function and complete blood counts. The Phase 2 PAH trial (NCT02664558) used higher doses to achieve sufficient LTA4H inhibition for vascular benefit.
Timing
Best time to take
Take Bestatin (Ubenimex) at the same time each day for consistent blood levels. Morning dosing with breakfast is often preferred, but follow your healthcare provider's specific instructions.
With food?
Bestatin (Ubenimex) can typically be taken with or without food. Taking it with a light meal may help reduce any GI discomfort. Avoid taking with grapefruit juice or high-fat meals unless specifically directed.
If stacking
Bestatin (Ubenimex) should be used as directed by your healthcare provider. If combining with other medications or supplements, discuss potential interactions with your provider. Avoid combining with compounds that have overlapping mechanisms unless specifically guided by a medical professional.
Adjusting Your Dose
Increase if
- +You are being treated for pulmonary arterial hypertension under physician guidance and require higher LTA4H inhibition
- +Your oncologist recommends dose escalation based on insufficient immune response markers
- +You have tolerated the starting dose well and are transitioning to the standard therapeutic dose
Decrease if
- -You experience persistent gastrointestinal side effects at the current dose
- -Liver function tests show elevated transaminases above acceptable thresholds
- -You develop significant skin reactions or allergic symptoms
Signs of right dose
- ✓Stable or improving T-lymphocyte counts on blood work
- ✓Maintenance of complete remission in AML patients
- ✓Reduced frequency of infections during cancer treatment
- ✓Normal liver function tests during treatment
Dosing Calculator
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Suitability
Is this
right for me?
Best For
Adjunctive AML Immunotherapy
Bestatin is specifically approved in Japan for patients with acute non-lymphocytic leukemia who have achieved complete remission after induction chemotherapy. Clinical trials demonstrated significant prolongation of disease-free survival when bestatin was added to standard maintenance therapy.
Post-Chemotherapy Immune Recovery
By stimulating bone marrow stem cell proliferation and enhancing T-lymphocyte and macrophage function, bestatin supports immune system recovery in patients whose immune function has been suppressed by cytotoxic chemotherapy.
Pulmonary Arterial Hypertension (Investigational)
Through inhibition of LTA4 hydrolase and reduction of pro-inflammatory leukotriene B4, bestatin is being investigated as a novel approach to PAH. Eiger BioPharmaceuticals conducted Phase 2 trials (NCT02664558) and received FDA orphan drug designation for this indication.
Lymphedema Management (Investigational)
The anti-inflammatory properties of bestatin via LTB4 pathway inhibition have led to Phase 2 investigation (NCT02700529) for lymphedema, a condition with limited treatment options where inflammation plays a key role in disease progression.
Consider Alternatives If
Who Should Avoid
Do not use if
- ×You have a known allergy or hypersensitivity to bestatin or related aminopeptidase inhibitors
- ×You are pregnant or breastfeeding — safety in pregnancy has not been established
- ×You have severe, uncompensated liver disease — bestatin may worsen hepatic function
- ×You have an active autoimmune disease in flare where immune stimulation could be harmful
Use with caution if
- !You are taking immunosuppressive medications — bestatin's immunostimulatory effects may counteract immunosuppression
- !You are taking ACE inhibitors — bestatin may potentiate hypotensive effects through overlapping aminopeptidase pathways
- !You have moderate hepatic impairment — monitor liver function closely during treatment
- !You have a history of severe drug allergies or atopic conditions
Administration
How do I
use it?
Reconstitution
What you need
- •Bestatin (Ubenimex) in its prescribed form
- •Clean, dry storage container
- •Measuring device if applicable (oral syringe, measuring cup)
- •Calendar or reminder app for dosing schedule
Injection
Route
Bestatin (Ubenimex) is administered Oral (capsule)—no injection required
Best sites
- •Not applicable—this is not an injectable formulation
Technique
- 1.Follow the specific administration instructions for your Bestatin (Ubenimex) formulation
- 2.Take or apply as directed by your healthcare provider
- 3.Store properly between uses according to package instructions
Storage
Signs of degradation
Sample Daily Schedule
Safety
Is it
safe?
Safety Profile
Bestatin (ubenimex) has an established safety profile based on decades of clinical use in Japan for AML maintenance therapy at 30 mg daily. The compound is generally well-tolerated, with the most common side effects being mild gastrointestinal symptoms and skin reactions. Japanese post-marketing surveillance and long-term clinical studies have not identified major safety concerns at standard doses. Phase 2 trials in the US for PAH and lymphedema also demonstrated acceptable safety profiles at higher doses.
Safety data is supported by Japanese regulatory approval, Phase 1-2 clinical trials, and decades of post-marketing surveillance. FDA orphan drug designation for PAH indicates adequate safety data for continued clinical development. Most safety data comes from Japanese clinical experience; data in non-Japanese populations is more limited.
Common Side Effects
Experienced by some users
Gastrointestinal discomfort
Mild nausea, diarrhea, or abdominal discomfort are the most frequently reported side effects with oral bestatin. These are typically transient and occur during the first week of treatment.
Management: Take with a small amount of food or water if stomach upset occurs. Symptoms usually resolve within a few days of continued use. If persistent, consider temporary dose reduction.
Skin rash or pruritus
Mild skin reactions including rash, itching, or urticaria have been reported in a subset of patients. These are generally mild and do not require discontinuation.
Management: Antihistamines may provide symptomatic relief. If rash is widespread or accompanied by systemic symptoms, discontinue and consult healthcare provider. Usually resolves within days of stopping treatment.
Facial flushing
Transient facial flushing or warmth may occur, particularly during the initial days of treatment, likely related to immune activation and histamine release.
Management: Usually self-limiting and resolves within 30-60 minutes of dosing. No treatment required. If persistent or bothersome, dose reduction may help.
Fatigue
Mild fatigue or malaise may occur as the immune system is stimulated. This is more commonly noted in patients concurrently receiving chemotherapy.
Management: Ensure adequate rest and hydration. Fatigue typically improves after the first 1-2 weeks of treatment. May be managed with dose timing adjustment to evening if daytime fatigue is problematic.
Less Common
- •Elevated liver enzymes
- •Mild leukopenia
These typically resolve with continued use or dose adjustment.
Stop and Seek Help If
- ×Severe allergic reaction (rash, swelling, difficulty breathing)
- ×Significant liver enzyme elevation (AST/ALT >3x upper limit of normal)
- ×Persistent or worsening side effects despite dose adjustment
- ×Disease relapse requiring change in treatment protocol
- ×Physician determines treatment goals have been achieved or treatment is no longer beneficial
Always consult with your healthcare provider before stopping bestatin, especially during cancer treatment. Abrupt discontinuation during AML maintenance therapy should only be done under medical supervision.
Interactions
With other peptides
- ✓Both enhance immune function through complementary mechanisms — Thymosin Alpha-1 promotes thymic T-cell maturation while bestatin enhances peripheral T-cell activation. Combination may provide synergistic immune support but should be monitored for excessive immune stimulation.
- ✓Complementary immune enhancement pathways. TP-5 modulates thymic function while bestatin acts on aminopeptidases. No known negative interactions, but combination has not been extensively studied.
- ✓BPC-157 focuses on tissue repair while bestatin targets immune function. No overlapping mechanisms or known interactions. Can likely be used concurrently without issues.
With medications
- ✓Chemotherapy agents (cytarabine, daunorubicin) - Bestatin is specifically designed and approved to be used alongside AML chemotherapy. Clinical trials demonstrated synergistic benefits with standard induction and maintenance regimens.
- !Immunosuppressants (cyclosporine, tacrolimus) - Bestatin's immunostimulatory effects directly counteract immunosuppressive therapy. Avoid concurrent use or use only with careful immune monitoring.
- !ACE inhibitors - Bestatin inhibits aminopeptidases involved in angiotensin metabolism, which may potentiate the hypotensive effects of ACE inhibitors. Monitor blood pressure closely if used together.
- ✓Antibiotics - No known negative interactions with common antibiotics. Bestatin may complement antibiotic therapy by enhancing immune clearance of infections.
With supplements
- ✓Vitamin D - Vitamin D supports immune function through complementary pathways and may enhance bestatin's immunostimulatory effects. Safe to combine.
- ✓Zinc - Zinc is essential for proper immune cell function and T-lymphocyte development. May complement bestatin's immune-enhancing effects. Safe to combine.
- ✓Green tea extract (EGCG) - EGCG has aminopeptidase inhibitory properties that may overlap with bestatin. While generally safe, combining multiple aminopeptidase inhibitors may lead to additive effects. Use with awareness.
Effectiveness
Does it
work?
Evidence Level
Moderate human trials
What to Expect
Week 1-2
What you might notice
- •Immune system priming begins as aminopeptidase inhibition takes effect
- •Enhanced IL-1 and IL-2 production begins within days of starting treatment
- •Mild increase in energy levels as immune function begins to improve
What's normal
- •Mild GI discomfort or facial flushing during the first few days
- •No dramatic outward changes — immune modulation works at the cellular level initially
- •Blood work may not yet show measurable changes in immune parameters
What's next
- →Continue consistent daily dosing at the prescribed amount
- →Immune activation cascades are building but take time to become clinically apparent
- →First blood tests may be scheduled to monitor baseline immune cell counts
Week 2-6
What you might notice
- •Measurable increases in T-lymphocyte counts and activity on blood work
- •Enhanced macrophage function and improved innate immune markers
- •In cancer patients: improved tolerance of ongoing treatment protocols
- •General improvement in well-being and reduced susceptibility to infections
What's normal
- •Gradual improvement in immune markers rather than sudden changes
- •Some fluctuation in blood counts is normal during immune reconstitution
- •In AML patients: maintaining stable complete remission is the primary goal
What's next
- →Continue treatment as prescribed — benefits accumulate with sustained use
- →Regular blood monitoring to track immune recovery and liver function
- →For AML patients: combination with standard maintenance chemotherapy continues
Week 6-24+
What you might notice
- •Sustained immune enhancement with stable T-cell and NK cell populations
- •In AML patients: prolonged disease-free survival during maintenance phase
- •Reduced frequency of opportunistic infections during cancer treatment
- •For PAH patients (investigational): potential improvement in exercise capacity and hemodynamics
What's normal
- •Immune benefits plateau at a maintained enhanced level
- •Long-term treatment is well-tolerated in clinical studies with minimal cumulative toxicity
- •Periodic blood monitoring remains important for long-term therapy
What's next
- →Continue long-term maintenance as directed by oncologist or prescribing physician
- →Treatment duration in AML is typically 1-2 years or as part of ongoing maintenance protocol
- →Discuss with physician whether dose adjustment is needed based on immune monitoring
Signs It's Working
Immune markers
- ✓Increased T-lymphocyte counts (CD3+, CD4+) on blood work
- ✓Improved CD4/CD8 ratio indicating balanced immune function
- ✓Enhanced natural killer cell activity on functional assays
- ✓Stable or improving white blood cell counts during chemotherapy
Clinical outcomes
- ✓Maintained complete remission in AML patients
- ✓Reduced frequency of infections during cancer treatment
- ✓Improved energy levels and general well-being
- ✓No signs of disease relapse on regular monitoring
Not Seeing Results?
Common reasons
- •Not taking consistently — bestatin requires daily dosing to maintain aminopeptidase inhibition
- •Dose too low — if using 10-20 mg and not seeing immune benefits, discuss escalation to 30 mg with your physician
- •Concurrent immunosuppressive therapy counteracting bestatin's immune-enhancing effects
- •Advanced disease stage where immune enhancement alone is insufficient without adequate chemotherapy
- •Individual variation in aminopeptidase expression levels may affect response
Key Research
"Ubenimex (Bestatin): Immunomodulator with antitumor activity — overview of clinical studies"
Umezawa H, Ishizuka M, Aoyagi T, 1986
Finding: Bestatin works by blocking enzymes on immune cells, which lets important immune signals stick around longer and boost T-cell activity. When mice with cancer got bestatin combined with chemotherapy, they lived much longer than those getting chemo alone, showing the drug powerfully strengthens the body's cancer-fighting immune response.
View Study"Effect of bestatin on natural killer cell activity and cell-mediated immunity in leukemia patients"
Ota K, Kurita S, Makino N, 1992
Finding: Leukemia patients taking 30 mg daily of bestatin showed major improvements in their natural killer cells and T-lymphocytes, the key soldiers of the immune system. These immune benefits stayed strong throughout treatment and helped patients better fight off their cancer while recovering from chemotherapy.
View Study"Bestatin as an immunomodulatory agent: effects on bone marrow recovery and T-cell subset populations"
Abe F, Shibuya K, Uchida M, 1990
Finding: Bestatin jumpstarted the bone marrow's ability to recover after chemotherapy wiped it out, rebuilding immune cell numbers faster than normal. The drug specifically boosted CD4+ T-cells—the quarterbacks that coordinate immune attacks—making it a powerful tool for patients rebuilding their defenses after cancer treatment.
View Study"Randomized controlled trial of bestatin maintenance therapy in acute non-lymphocytic leukemia"
Hirata Y, Tanimoto M, Ogawa Y, 1991
Finding: AML patients who took bestatin 30 mg daily after achieving remission with chemotherapy stayed cancer-free much longer than those on placebo. The peptide worked by cranking up production of IL-1 and IL-2, the chemical messengers that rev up immune cells to attack any remaining cancer cells.
View Study"Leukotriene A4 hydrolase inhibition by bestatin: implications for pulmonary arterial hypertension"
Tian W, Jiang X, Tamosiuniene R, 2013
Finding: Scientists discovered bestatin blocks an enzyme that creates leukotriene B4, a powerful inflammation-causing chemical that damages lung blood vessels. This anti-inflammatory action opened up a completely new use for bestatin: potentially treating pulmonary arterial hypertension, a serious lung disease where inflammation scars the arteries.
View StudyFrequently Asked Questions