Methionine
| Evidence Level: L4 | Predicted Indications: 10 |
Table of Contents
Methionine: From an Amino Acid Supplement (No Listed Indication) to Acne
One-Sentence Summary
Methionine is an essential sulfur-containing amino acid, marketed in the US as liquid supplement products, and the regulatory data lists no approved indication. The TxGNN model predicts it may be effective for Acne, but there are 0 clinical trials and only 4 publications, none of which tests methionine as an acne treatment.
Quick Overview
| Item | Content |
|---|---|
| Original Indication | Not listed in the regulatory data |
| Predicted New Indication | Acne (disease) |
| TxGNN Prediction Score | 99.9996% |
| Evidence Level | L4 |
| US Market Status | ✓ Marketed |
| Number of NDAs | 2 |
| Recommended Decision | Hold |
Why is This Prediction Reasonable?
Currently, detailed mechanism of action data is not available. Methionine is a building block for proteins and a precursor in one-carbon metabolism (homocysteine, cysteine and glutathione). No approved original indication is recorded, so there is no established efficacy to extend to acne.
The only link to acne is indirect. One cohort study found elevated plasma homocysteine in patients taking isotretinoin for cystic acne. That observation concerns a drug side effect and does not test methionine as a treatment. The other three papers cover an MTHFR mutation case, neutrophil chemotaxis in inflammatory skin disease, and Sweet’s syndrome. They are not relevant to acne therapy.
The TxGNN score is near 1.0 for many candidates and does not discriminate between them. It should not be read as clinical support. Because methionine can raise homocysteine, this direction also carries a possible safety concern.
For context, the other top predictions are mostly cataract subtypes plus severe nonproliferative diabetic retinopathy. Diabetic cataract has the most plausible mechanism (methionine sulfoxide reductase and homocysteine biology), but that evidence is preclinical or review-level.
Clinical Trial Evidence
Currently no related clinical trials registered.
Literature Evidence
| PMID | Year | Type | Journal | Key Findings |
|---|---|---|---|---|
| 11277950 | 2001 | Cohort | Int J Dermatol | Plasma homocysteine was elevated in patients on isotretinoin for cystic acne. Methionine was not tested as a treatment. |
| 39357918 | 2024 | Case report | BMJ Case Reports | Neonate with a novel MTHFR mutation, encephalopathy, hair loss and neonatal acne. Not relevant to acne therapy. |
| 3161955 | 1985 | Lab/observational | J Invest Dermatol | Neutrophil C5a-specific function was transiently absent in inflammatory skin disorders, including acne conglobata. Not related to methionine. |
| 3859500 | 1985 | Case report/lab | J Am Acad Dermatol | Increased plasma chemoattractant in a patient with Sweet’s syndrome and cystonodular acne. Not related to methionine. |
US Market Information
| Authorization Number | Product Name | Dosage Form | Approved Indication |
|---|---|---|---|
| Not available | L-Methionine High | Liquid | Not listed |
| Not available | L-Methionine | Liquid | Not listed |
Both products are made by Professional Complementary Health Formulas.
Safety Considerations
Please refer to the package insert for safety information.
Conclusion and Next Steps
Decision: Hold
Rationale: The prediction rests on the model score alone. There are no trials, and the only acne-related human data is an observation of raised homocysteine on isotretinoin, which does not support methionine as a treatment. Safety data is also missing, and methionine’s effect on homocysteine adds a possible concern.
To proceed, the following is needed:
- Package insert warnings and contraindications, which block any safety screening
- Mechanism of action data (for example from DrugBank)
- Evidence that links methionine or one-carbon metabolism to acne, such as preclinical or observational studies
- A homocysteine safety assessment before any clinical test
- A comparison with the diabetic cataract direction, which has a more plausible mechanistic thread, when deciding where to focus
This report is for research reference only and does not constitute medical advice. Repurposing candidates require clinical validation before any clinical use.
Disclaimer
This content is for research purposes only and does not constitute medical advice. Clinical validation is required before any clinical application.