Some interesting cases/scenario where testosterone level in the body can be increased::

No 1:

Experts recommend one of the safest ones and most importantly legal ones is to increase zinc mineral intake.Also brewers yeast, whole grains and wheat have high levels of zinc in them and they are totally natural.The minimal dose of zinc for men is 15 mg per day, but up to 50 mg daily can be taken, anything more than that can cause unwanted side effects and can be hazardous for your health.

No 2:

In a 2003 study, it show that serum testosterone levels reach a peak seven days after abstaining from ejaculation.

No. 3:

Recent research has suggested that alcohol consumption in women can temporarily raise testosterone levels. A 2006 BBC article states : “ According to medical research, testosterone- the homone connected to male characteristics such as aggression and sex drives –rises in women by up to 50% when they drunk. In men, it falls”