Sacha inchi is a perennial plant with somewhat hairy leaves. The plant reaches a height of 2 m (6′ 6″), with alternate, heart shaped, serrated leaves, 10 to 12 cm long (4″-4.7″) and 8 to 10 cm (3.1-3.9″) wide, that have petioles 2–6 cm (0.8-2.3″) long. It flowers five months after being planted, and bears seeds around the eighth month. The male flowers are small, white, and arranged in clusters. Two female flowers are located at the base of the inflorescence.
The fruits are capsules of 3 to 5 cm in diameter with 4 to 7 points, are green and ripen blackish brown. On ripening, the fruits contain a soft black wet pulp that is messy and inedible, so are normally left to dry on the plant before harvest. Fruit capsules usually consist of four to five lobes, but some may have up to seven. Inside are the seeds, oval, dark-brown, 1.5 to 2 cm in diameter and 45 to 100 grams of weight.