Nipple tenderness does not necessarily indicate ovulation. While nipple tenderness is a symptom some people may experience during ovulation, it doesn't always mean it's ovulation. In fact, nipple tenderness can have a variety of causes, including breast massage, tight underwear, changes in hormonal levels, infection, and more.

Therefore, nipple tenderness is not the only criterion for judging ovulation. If you want to determine your ovulation period, it is recommended to measure your basal body temperature or observe your menstrual cycle to determine it. In addition, you can also consult a doctor, who will determine the ovulation period based on personal circumstances.

If you suspect that you have nipple tenderness, it is recommended to seek medical advice promptly and seek professional help.