Methionine
| Evidence Level: L5 | Predicted Indications: 10 |
Table of Contents
Methionine: From Essential Amino Acid Supplementation to Acne
One-Sentence Summary
Methionine is an essential sulfur-containing amino acid with no recorded UK marketing authorisation and no confirmed original therapeutic indication in this evidence pack. The TxGNN model predicts it may be relevant to Acne, but this is supported only by 4 mechanistic/observational publications and no clinical trials, and the underlying rationale points in a potentially contradictory direction.
Quick Overview
| Item | Content |
|---|---|
| Original Indication | Not available — no approved indication or licence data on file; methionine is generically known as an essential amino acid used in metabolic/nutritional contexts |
| Predicted New Indication | Acne (disease) |
| TxGNN Prediction Score | 99.9996% |
| Evidence Level | L4 (preclinical/mechanistic studies only, no RCTs) |
| UK Market Status | Not marketed |
| Number of Marketing Authorisations | 0 |
| Recommended Decision | Hold |
Why is This Prediction Reasonable?
Currently, detailed mechanism of action data is not available for methionine in this evidence pack. Based on known pharmacology, methionine is an essential amino acid and precursor in the homocysteine/S-adenosylmethionine (SAM) and transsulfuration pathway, which also feeds into glutathione (GSH) biosynthesis. No confirmed original indication or UK licence exists for this compound, which limits the extent to which mechanistic continuity with the predicted new use can be assessed.
For the top-ranked prediction, acne, the supporting literature does not describe methionine as a treatment. Instead, it shows that isotretinoin therapy for cystic acne is associated with a rise in plasma homocysteine as a side effect, and two older papers describe neutrophil function in inflammatory skin conditions without any direct link to methionine supplementation. This means the mechanistic direction is unclear and may even run counter to a therapeutic rationale — elevated homocysteine is generally regarded as an adverse metabolic effect, not a marker of efficacy.
Overall, the link between methionine’s known biology and acne is mechanistically plausible only in the loosest sense (shared metabolic pathway), but the available evidence does not demonstrate — and in one instance arguably contradicts — a therapeutic effect. This should be treated as a hypothesis-generating signal only.
Clinical Trial Evidence
Currently no related clinical trials registered.
Literature Evidence
| PMID | Year | Type | Journal | Key Findings |
|---|---|---|---|---|
| 11277950 | 2001 | Cohort | International Journal of Dermatology | Isotretinoin therapy for cystic acne was associated with elevated plasma homocysteine, a downstream metabolite of methionine — a side-effect observation, not a treatment finding |
| 39357918 | 2024 | Case Report | BMJ Case Reports | Neonate with MTHFR mutation presented with neonatal acne among other dysmorphic features; illustrates a metabolic disease association, not a treatment link |
| 3859500 | 1985 | Case Series | Journal of the American Academy of Dermatology | Neutrophil chemotaxis findings in a patient with Sweet’s syndrome and cystic acne; no methionine intervention studied |
| 3161955 | 1985 | Case Series | Journal of Investigative Dermatology | Neutrophil function studied across various inflammatory skin diseases including acne; no methionine intervention studied |
UK Market Information
Methionine currently holds no UK marketing authorisation on file (market status: Not marketed; 0 licences recorded). No product-level dosage form or approved indication text is available for this compound.
Safety Considerations
Please refer to the SmPC and BNF for safety information. Report suspected adverse reactions via the Yellow Card Scheme.
Note: regulatory safety documentation (warnings, contraindications) for this compound is currently missing from source data and is flagged as a blocking data gap — this must be resolved before any further evaluation (see Next Steps).
Conclusion and Next Steps
Decision: Hold
Rationale: The evidence for methionine in acne consists solely of preclinical/observational and case-level literature (L4) with no clinical trials, and part of the available evidence points toward homocysteine elevation as an adverse effect rather than a therapeutic mechanism. Combined with the absence of any UK marketing authorisation and missing regulatory safety documentation, the evidence base does not currently support progression.
To proceed, the following is needed:
- TFDA/MHRA-equivalent product labelling (warnings and contraindications) — currently a blocking data gap
- Confirmed mechanism of action and an established original indication for methionine, to properly assess mechanistic continuity
- Targeted, controlled studies testing methionine (not homocysteine as a biomarker of another drug’s toxicity) as an intervention in acne
- Clarification of the direction of the homocysteine/methionine relationship in dermatological conditions before further mechanistic claims are made
Note: this evidence pack also contains several lower-ranked cataract-related predictions (ranks 3, 5, 6, 10) built on a shared glutathione-precursor rationale, each similarly limited to preclinical evidence (L4/L5) with no clinical trials. These may warrant separate evaluation but do not change the Hold recommendation for the primary candidate above.
Disclaimer
This content is for research purposes only and does not constitute medical advice. Clinical validation is required before any clinical application.