Early signs of male puberty are increased testicle and penis sizes followed by noticeable pubic and armpit hair. Next signs are a deeper voice, muscle enlargement and appearance of facial hair, per MedicineNet. Other signs include a growth spurt, more sweat and acne, states MedlinePlus.
Beginning around age 11, the first observation of puberty in boys is testicle growth followed after about six months by penis enlargement. Appearance of armpit and pubic hair is the next sign, according to MedicineNet.
As the voice box, larynx and vocal cords grow, a boy's voice cracks and squeaks. This leads to a deeper voice. Muscle growth follows. Often facial hair is the final puberty stage, says MedicineNet.
A growth spurt happens about two years after puberty. Hormone changes during puberty increase acne indicates MedlinePlus. Hormones also intensify sweat and sweat smell.