According to one aspect of the present disclosure, an ultra-low voltage current reused voltage-controlled oscillator and transconductance-capacitor filter is provided. The circuit includes a voltage-controlled oscillator stacked atop a transconductance-capacitor filter. The voltage-controlled oscillator includes a node one, a node two, a node three, a node four, an inductance, a variable capacitor, a first switched element, a second switched element, a third switched element, and a fourth switched element. The transconductance-capacitor filter includes a first resistor, a second resistor, a fifth switched element, a sixth switched element, a seventh switched element, and an eighth switched element.