Syphilis can cause a painless sore (chancre) on the lip in its primary stage, but this appears as an ulceration, not a brown or black spot
Symptoms like hair loss, fatigue, flaky skin, or bruising, muscle weakness, poor wound healing may indicate insufficiency (Mozafariun et al 2025)
Sharma, A., Parachuri, N., Kumar, N., Saboo, B., Tripathi, H.N., Kuppermann, B.D
Results Validation Success: Method validated per ICH M10 guidelines for 1500 ng/mL range Stability: Demonstrated 64-day stability at both 20C and 80C Selectivity: Chromatograms free of interferences across all plasma types Matrix Effects: Assay free of matrix effects across all plasma types
J Nutr Intermed Metab
Research indicates unwanted effects such as facial flushing, nausea, vomiting, and possible changes in mole pigmentation in research models