Science
Mechanism of Action
On the skin, methotrexate primarily acts by slowing the rapid proliferation of skin cells, a characteristic of conditions like psoriasis. It exerts anti-inflammatory effects by increasing intracellular adenosine and modulates immune responses by reducing T-cell migration to the skin, decreasing oxidative inflammation in immune cells, and inhibiting the release of pro-inflammatory cytokines such as TNF-α, IL-10, and IL-12. At higher therapeutic doses, it also functions as an antimetabolite, interfering with DNA synthesis by antagonizing folic acid.
Research
Clinical Evidence
High confidenceN/A
Key findings
- 01 Topical applications of methotrexate have demonstrated efficacy in treating localized psoriasis. A 1% methotrexate gel led to a 29.16% reduction in Erythema, Scaling, and Induration (ESI) scores over 6 weeks, particularly for lesions on palms and soles.
- 02 An azone gel vehicle containing 0.1% to 1% methotrexate proved superior to placebo for plaque-type psoriasis.
- 03 Methotrexate at 0.05% delivered via liposomes significantly reduced psoriasis severity.
- 04 However, a 0.25% methotrexate cream was noted to have no clinical or histological effect on psoriatic skin, despite being absorbed, highlighting the critical importance of formulation in its efficacy.
Transparency
Dusting Analysis
Methotrexate is a highly potent pharmaceutical ingredient used exclusively in prescription medications, not a cosmetic ingredient. The concept of 'dusting' for superficial cosmetic claims is entirely inapplicable and inappropriate for this substance.
The Formula
Formulation
Stability
Methotrexate displays optimal chemical stability at pH 7.00. However, it can show instability under physiological pH and temperature conditions over prolonged periods (48 hours). For optimal preservation, it must be protected from light and stored within a temperature range of 15°C to 30°C. While methotrexate free acid is practically insoluble in water, its sodium salt is soluble in water.
Conflicts
- Alcohol (potential for increased liver problems)
- Non-steroidal anti-inflammatory drugs (NSAIDs), including salicylates (may increase toxicity)
- Ultraviolet (UV) radiation (can aggravate psoriasis and induce photodermatitis/sunburn reactivation)
Safety
Safety Profile
Methotrexate is an FDA-approved prescription medication for serious medical conditions and is not evaluated by cosmetic regulatory bodies like CIR or SCCS. Its usage necessitates careful medical supervision due to a significant risk of severe side effects. These can include severe dermatologic reactions such as photosensitivity, widespread skin rash, itching, hives, redness, blistering, peeling, or loosening of the skin. Pregnancy safety requires strict medical consultation due to its classification as a potent drug.
Your Skin
Skin Compatibility
Our Assessment
Verdict
Methotrexate is a potent, FDA-approved prescription drug with significant side effects and strict usage requirements, rendering it wholly unsuitable and unsafe for inclusion in cosmetic skincare formulations.
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References
Sources