How hormones change our breath

A PTR-MS (Proton Transfer Reaction Mass Spectrometer)

What do hormones and breath have to do with each other?

Apparently nothing, in reality A LOT!

In two previous posts (1 and 2) I talked about mass spectrometry and in particular about PTR-MS.

PTR-MS is a particular mass spectrometer which is able to measure volatile molecules (called VOCs). I use it for food analysis, but it has applications also in environmental and medical sciences.

In this post I want to talk about a paper published in 2018 by Sukul and collaborators.

They analyzed the breath of 24 healthy women using PTR-MS. Half of this women used oral contraception, the other half had a natural menstrual cycle.

Hormones involved in the menstrual cycle are estrogen and progesterone. Women with a natural menstrual cycle have increasing level of estrogen from day 1 (first day of bleeding) to day 14 (ovulation day), afterwards the concentration of estrogen lowers and the one of progesterone raises till day 28 (last day of cycle).

Breath analysis via PTR-MS shows differences in VOCs concentration during the 28 days of menstrual cycle. These changes overlap the estrogen and progesterone regulation.

Breath exhalation of women with oral contraception differs greatly from the one of women without it. The main changes happen with the following VOCs:

  • Ammonia, which is the result of protein metabolism and its exhalation depends on changes of blood pH. Women with oral contraception show similar level of ammonia during the whole menstrual cycle, while women without oral contraception have a decrease of ammonia during ovulation.
  • Acetone, which is the result of glucose metabolism. Women without oral contraception have a rise in acetone exhalation during estrogen rise. On the contrary, the level of acetone in women with oral contraception is more or less the same during the whole cycle.
  • DMS, which is due to gut bacterial colony. Women with oral contraception exhale almost zero DMS, due to the fact that synthetic progesterone can have an antibacterial effect on gut bacteria.

PTR-MS could be use as noninvasive technique to monitor the health of women.


Sukul et al., “Natural menstrual rhythm and oral contraception diversely affect exhaled breath compositions”, (2018),


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