Can I use this alongside muscle rubs, magnesium sprays, or pain-relief gels?

This is a cosmetic cooling balm, not a medicated analgesic, so it doesn't contain NSAIDs, lidocaine, or capsaicin. That means it generally won't interact chemically with magnesium sprays, arnica gels, or OTC pain-relief creams. However, many of those products also contain menthol or camphor for sensory effect. Layering several mentholated products at once can amplify the cooling sensation to the point of irritation — especially on thinner skin (inner arms, neck, behind knees). A practical approach: if you use a magnesium spray, apply it first on clean skin and let it dry (5–10 minutes). Then apply the balm for massage and the cooling feel. If you use a medicated gel (ibuprofen, diclofenac, etc.), follow the gel's own label — usually it wants clean, product-free skin and a wait time before covering. Don't apply the balm over a fresh medicated layer unless your pharmacist or doctor says it's fine. And always wash hands between different products to avoid cross-contamination of active ingredients.