It's becoming increasingly recognised in the arenas of bodybuilding, elite sport and fitness, that the menstrual cycle has an affect - in some athletes a very profound one - upon metabolism and the ways in which macronutrients and used and stored by the body. During the follicular phase (the first half of the cycle), insulin sensitivity is higher, and carbohydrates are more readily employed to fuel muscle gains. During the luteal phase, the body relys more heavily upon fat as a fuel source. It has also been noted that there is a 3-11% increase in energy expenditure during the week prior to menstruation.
But, did you know that hormones also affect your tan?
The pH and moisture level of the skin are both very important variables in terms of the quality and longevity of a fake tan. Applying a tan onto dry skin can result in an uneven resulting tan, and patchy fade-off. The skin is more prone to dryness during menstruation, and also for women in the perimenopausal and menopausal phases of life, where oestrogen levels drop. In addition, the lower levels of oestrogen can (somewhat paradoxically) result in the dominance of other hormones which can result in oily skin, and a loss of the skin's natural 'barrier function,' resulting in greater moisture loss and skin dryness (WilliamSkinGene, 2009).
Skin pH also varies throughout the cycle, which can also have a profound affect upon your tan. The author of 'Pale Skin Fighters,' who runs a salon in California, recently posted this personal account of how much the menstrual cycle can alter the skin's pH and affect the quality of a tan:
"I, personally, experienced this when on my period. I noticed that when not using a pH balancing prep product, the upper area of both my thighs, as well as my arms, both didn't hold a tan and started to fade roughly. When going through my cycle but using a pH balancing prep product, my tan came out perfect. I also experimented with this on a friend. She was having her period and didn't use a pH prep spray. Her arms came out with white spots on them and her tan started fading very roughly. We tanned her on her cycle with a pH prep, and she came out just fine. I can really only draw one thing from this-the pH is affected by your hormones, which in turn leads to uneven spray tans. The only way to combat this is to first balance the pH on the skin's surface, and then spray with the tanning solution."
Whether a pre-tan prep spray can balance the pH of the skin for long enough to truly counter the affects of hormonal changes remains hotly debated, however, there is little doubt that it can help during the application phase, and allow the product to correctly penetrate the skin. Thus, it is certainly an important step in ensuring a smooth, even application every single time.
As well as during menstruation itself, on 'ovulation day' (halfway through the cycle), a woman's skin becomes very sensitive and will be prone to allergic reactions, e.g. from pollen.
As well as hormonal changes (and another obvious omission from this article is spray tanning during pregnancy), other factors which can affect the skin's pH are stress, diabetes or lupus, and the type of products being used (harsh or irritating cleansers or creams).
References & further reading:
Jonge, J. (2003). Effects of the menstrual cycle on exercise performance. Sports Medicine, 33(11).
Oosthuyse, T., Bosch A. (2010). The effect of the menstrual cycle on exercise metabolism: implications for exercise performance in eumenorrhoeic women. Sports Medicine, 40(3).