Testosterone Support + Anti Estrogen! Powerful Multi-Phase Test Booster For Muscle, Libido, Strength And Performance! Testosterone Support + Anti Estrogen. Muscle. Libido. Strength. Performance. Powerful Multi-Phase Test Booster for Muscle, Libido, Strength and Performance! ISA-TEST GF is high performance testosterone booster comprised of a precise combination of natural ingredients clinically shown to cause increases in testosterone and a reduction in the 'female-hormone' estrogen. ISA-TEST GF is designed to promote noticeable gains in strength, increased muscle mass, and improved sexual drive and performance. Note: Manufacturers continually change product specifications. While we try our best to keep product descriptions up to date, they do not necessarily reflect the latest information available from the manufacturer. We are not responsible for incorrect or outdated product descriptions and/or images.