Oily hair and skin before your period: what your hormones are telling you

Some days, your hair is (very) much worth it. Other days, it has clearly decided to sabotage your morning: flat, greasy, frizzy, unwilling to cooperate. Spoiler alert: it's neither your shampoo's fault nor the moon's. The real culprit is hiding on the side of your ovaries. Estrogen, progesterone, testosterone: this trio performs a well-orchestrated hormonal dance throughout the month, and your scalp follows the choreography, whether it agrees or not. We explain the mechanism, hormone by hormone, to stop blaming your hair (it's not them, it's your ovaries).

Key takeaways (for those short on time)

Your sebaceous glands have hormone receptors, just like your skin. As a result, estrogen calms sebum production, while testosterone steps on the gas. Progesterone's role, however, remains debated by dermatologists. This hormonal shift explains why your hair is sublime around ovulation... and why it completely ignores you just before your period. To know exactly where you stand, head to our guide on how to calculate your menstrual cycle.

Why is my hair greasy before my period? The fault of the progesterone + testosterone duo

If your hair becomes greasy again the day after shampooing in the days leading up to your period, the most common explanation points to a hormonal duo: progesterone (still well established since ovulation) and a second small peak of testosterone.

The idea that progesterone stimulates sebum production is widely held, including by several healthcare professionals. However, it deserves to be nuanced: Indian dermatologist Dr. Sangita Ghosh, in a benchmark review published in theIndian Journal of Dermatology, reminds us that this link has never been formally demonstrated experimentally in humans, and that progesterone even acts, biochemically, as a competitive inhibitor of the enzyme responsible for sebum activation by testosterone, a mechanism that should rather slow it down [1].

This is what American dermatologists John S. Strauss and Albert M. Kligman had already observed in the 1960s: the effects of progesterone on sebaceous glands vary according to studies and do not follow as simple a pattern as is often thought [2].

What is, however, firmly established, is the small pre-menstrual testosterone peak: a large-scale study by Prof. Christos Zouboulis involving over 17,000 women confirms the role of testosterone (via its conversion to DHT by 5α-reductase) in stimulating sebum [3].

💡 Smart tip: during this period, forget ultra-nourishing masks (your scalp doesn't need extra help to get greasy) and opt for a lighter, purifying shampoo.

Why is my hair at its best during ovulation? The secret to a "Good Hair Day"

Conversely, around ovulation, estrogen levels peak, and for once, they work in your favor. Unlike other hormones, estrogen has a rather calming effect on sebum: a recent study shows significantly lower sebaceous production during the ovulatory phase than at the beginning of the luteal phase [4]. At the same time, a slight testosterone peak counteracts what is happening. The result: an almost perfect balance between a hormone that slows down sebum and another that activates it just enough to give volume and shine. The winning combination.

The personality profile of the 3 hormones that dictate your good or bad hair day

This same hormonal trio also explains variations in female libido throughout the cycle.

And what about the skin?

Your skin follows the exact same hormonal logic as your hair, phase by phase, which is logical, since the same hormones control the sebaceous glands. Estrogens also play a broader protective role on the skin: beyond their effect on sebum, they contribute to maintaining skin thickness and collagen production, a mechanism documented in estrogen deficiency during menopause, and which can reasonably be extrapolated to the finer variations of the cycle [5]. Other body signals also evolve by phase, such as the evolution of cervical mucus throughout the cycle.

💡 The right reflex: schedule active treatments (retinol, exfoliants, peels) during the follicular phase and ovulation, when the skin is most tolerant, and lighten your routine (for both skin and hair) from the second half of the cycle.

How to adjust your hair care routine according to the cycle phase

The same principle applies far beyond hair care routines: your energy and physical performance follow the same logic, as we explain in our article on organizing your sports practice according to your cycle.

When it's more than just "a cycle thing"

Some hormonal imbalances go far beyond a simple bad hair day, and then, we stop joking:

• PCOS (Polycystic Ovary Syndrome): The excess of androgens it causes is associated with alopecia affecting the top of the head. A benchmark meta-analysis conducted by Prof. Enrico Carmina, an endocrinologist, for the Androgen Excess and PCOS Society, estimates the prevalence of this alopecia at 28% in women with PCOS (confidence interval: 22 to 34%) [6]. The link between excess androgens and hair loss is also widely documented in the literature on the mechanisms of androgenetic alopecia [7].
• Hypothyroidism: can make hair softer, more brittle, with more noticeable shedding.
• Puberty, postpartum, perimenopause: these major hormonal shifts can also affect hair density and texture, sometimes more permanently — we detail what happens in our article on our hormones in perimenopause.

⚠️ The real alarm signal: a real loss of density (not just a bad day), especially on the top of the head, or hair loss that lasts several weeks. Consult a doctor and, if necessary, get a blood test.

What we remember

Your hair doesn't have a personal vendetta against you, even if everything seems to suggest otherwise on a bad morning. It faithfully follows the hormonal logic of your cycle: estrogen in regulator mode, testosterone in activator mode, progesterone with a still debated role, without ever giving you advance warning. Once you've identified this logic, you can adjust your routine.

Frequently asked questions

Why does my hair get greasier faster after ovulation?
The most common explanation points to progesterone, which takes over after ovulation. Its exact role on the sebaceous glands is still debated by dermatologists; the small testosterone peak that accompanies it, however, has a well-established stimulating effect on sebum.

Does the pill change things?
Yes: by pausing the natural hormonal cycle, the pill tends to smooth out these variations. What we describe here mainly concerns cycles not treated with hormonal contraception.

When should you worry about hair loss?
If the loss of density is real (not just a different texture on a given day) and persists for several weeks, it's best to talk to a healthcare professional.