# Meet your hormones > Oestrogen, progesterone, LH, FSH and testosterone, minus the jargon. Category: Cycle basics · 5 min read · Written by the Splash team · Sources checked October 2026 URL: https://splash.care/learn/cycle-basics/hormones-explained ## Quick answer - The brain sends GnRH, FSH and LH to direct the ovaries. - Oestrogen builds; progesterone steadies things after ovulation. - The LH surge triggers ovulation and is what LH tests measure. - Everyone with ovaries makes some testosterone. - One hormone test is only a snapshot, so timing and symptoms matter. Hormones are chemical messengers. In your cycle, a handful pass notes back and forth between your brain and your ovaries. Here is who does what. ## The brain bosses: GnRH, FSH and LH The hypothalamus releases [GnRH](https://splash.care/learn/glossary/gnrh) in pulses, which tells the pituitary gland to release two hormones: - **FSH** ([FSH](https://splash.care/learn/glossary/fsh)): rises at the start of the cycle and tells follicles in the ovary to grow. - **LH** ([LH](https://splash.care/learn/glossary/lh)): stays fairly low, then surges just before [ovulation](https://splash.care/learn/glossary/ovulation) and triggers the egg's release. This surge is what [ovulation test](https://splash.care/learn/fertility-ttc/lh-tests-how-to) strips pick up. ## Oestrogen: the builder [Oestrogen](https://splash.care/learn/glossary/oestrogen) (spelled estrogen in the US) is made mainly by growing follicles. It thickens the womb lining and makes [cervical mucus](https://splash.care/learn/glossary/cervical-mucus) slippery. It also supports bones, skin, and the heart and blood vessels. It peaks just before [ovulation](https://splash.care/learn/phases/ovulation), dips, then has a smaller second rise in the [luteal phase](https://splash.care/learn/glossary/luteal-phase). ## Progesterone: the steadier [Progesterone](https://splash.care/learn/glossary/progesterone) is made by the [corpus luteum](https://splash.care/learn/glossary/corpus-luteum) after ovulation. It keeps the womb lining stable, thickens [cervical mucus](https://splash.care/learn/body-literacy/mucus-and-cervix), and raises your resting temperature a little. When it falls at the end of the cycle, your period starts. Its rise is why temperature [tracking](https://splash.care/learn/cycle-basics/tracking-101) can confirm ovulation has already happened. ## Testosterone: yes, you have some too Ovaries and adrenal glands make small amounts of testosterone. It plays a part in [libido](https://splash.care/learn/glossary/libido), muscle and bone, and your body also converts it into oestrogen. Higher-than-usual levels, such as in [PCOS](https://splash.care/learn/glossary/pcos) (which the NHS now also calls [PMOS](https://splash.care/learn/glossary/pmos)), can show up as acne, extra hair growth or [irregular periods](https://splash.care/learn/cycle-basics/irregular-cycles). - **Period:** Oestrogen and progesterone at their lowest; FSH starting to rise. - **Follicular:** Oestrogen climbing steadily. - **Ovulation:** Oestrogen peaks and LH surges. - **Luteal:** Progesterone high, oestrogen moderate, then both fall before your period. ## Can a test tell me my hormone levels? It can, but one result is a snapshot of a moving target. Your levels change through the cycle and even through the day, so the timing of a blood test matters and results are only meaningful alongside your symptoms and cycle dates. NICE advises against routine hormone testing for heavy periods, for example. Home hormone kits and "hormone panels" sold online are not a shortcut to a diagnosis. **Myth:** Oestrogen is "good" and progesterone is "bad", or the other way round. **Fact:** Each hormone has its own jobs and you need both. Problems tend to come from hormones being out of step with each other or with what the body needs, not from one hormone being the villain. > **Splash says:** hormonal contraception changes this pattern on purpose. Some methods stop ovulation, so on those your "phases" may look different. That is expected. ### When to see a doctor Talk to a GP if you notice new thick, dark hair on your face or body, severe acne, periods stopping for 3 months in a row, or very irregular cycles. They may do blood tests and decide when in your cycle to take them. Ask for an urgent appointment if thick, dark hair appears suddenly together with a deepening voice or growing muscles. **Quick quiz:** Which hormone do ovulation (LH) tests detect? 1. Progesterone 2. Luteinising hormone 3. Testosterone Answer: Luteinising hormone. LH surges before ovulation (a positive result usually means ovulation within about 36 hours), and the strips detect it in your wee. ## Sources 1. [Cleveland Clinic: Estrogen](https://my.clevelandclinic.org/health/articles/22353-estrogen) 2. [Cleveland Clinic: Progesterone](https://my.clevelandclinic.org/health/body/24562-progesterone) 3. [Cleveland Clinic: Ovulation](https://my.clevelandclinic.org/health/articles/23439-ovulation) 4. [Cleveland Clinic: Follicular phase](https://my.clevelandclinic.org/health/body/23953-follicular-phase) 5. [NHS: Polyendocrine metabolic ovarian syndrome (PMOS, formerly PCOS)](https://www.nhs.uk/conditions/polyendocrine-metabolic-ovarian-syndrome-pmos/) 6. [NICE NG88: Heavy menstrual bleeding: assessment and management](https://www.nice.org.uk/guidance/ng88/chapter/Recommendations) This is general information, not medical advice. Splash can’t diagnose. If you’re worried, talk to a GP, pharmacist or sexual health clinic. In an emergency call 999 (UK) or 911 (US).