Your Cyclopedia: The Ultimate Glossary of all Things Hormonal Health

Acne: A common skin condition that occurs when your hair follicles become blocked by oil and dead skin cells.

Amenorrhea: The absence of a natural menstrual bleed (or missing a period).

Androgens: A group of steroid hormones - (the most well known being testosterone). You may often hear of androgens being referred to as ‘male sex hormones' but they’re important for both male and female sexual reproduction and development.

Anovulation: When the ovaries stop releasing eggs. Anovulation could signify an underlying hormonal imbalance or be related to a specific condition, such as polycystic ovary syndrome (PCOS). It may also occur in response to stress, extreme exercise or a sudden change in body weight. Importantly, it is perfectly normal to experience anovulation if you have just started your periods, or are perimenopausal (approaching menopause).

Cervical cap: Reusable, soft silicone cups that are inserted into the vagina before you have sex. They cover the cervix to prevent sperm from entering the uterus and need to be used with a spermicide - a chemical that further reduces the risk of pregnancy by killing sperm.

Combined Hormonal Contraception (CHC): Contraceptives that contain both estrogen and progestogen. There are lots of different types of CHC. The most widely used are combined oral contraceptive (COC) pills. There is also the combined contraceptive ring and the combined contraceptive patch.

Combined Oral Contraception (COC): Also known as the combined pill. COC pills contain both estrogen and progestogen. They prevent ovulation by decreasing your production of FSH and LH. This thickens your cervical mucus (making it difficult for sperm to swim through) and thins the lining of your uterus to reduce the likelihood that an egg (if it has already been released) will attach to your uterus wall.

Contraceptive Patch: A combined hormonal contraceptive (CHC). It’s applied to the skin where it releases a dose of progestogen and estrogen into the blood, every 24 hours. It has to be replaced every week, for 3 weeks and is then followed by a patch-free week.

Contraceptive ring: A combined hormonal contraceptive (CHC). It’s inserted into the vagina where it continually releases a dose of progestogen and estrogen into the blood, every 24 hours. It is kept in place for 3 weeks and is then removed for 1 week. Following the ring-free week, you then have a new ring inserted. This is kept in place for another 3 weeks.

Copper IUD (Non-hormonal IUD): Also known as ‘the copper coil’. It is a small T-shaped device that is inserted into your uterus by a healthcare professional. The copper IUD provides continuous contraception for a period of up to 5 or 10 years (depending on the type of IUD you have inserted).

Diaphragm: Reusable, soft silicone domes that are inserted into the vagina before sex. They cover the cervix to prevent sperm from entering the uterus and need to be used with a spermicide—a chemical that further reduces the risk of pregnancy by killing sperm.

Dopamine: A hormone associated with pleasure and reward - basically dopamine makes us feel good. Many hormones can affect your dopamine levels (estrogen is a key example!)

Dysmenorrhea: When you experience pain and/or cramping during or around the time of your menstrual bleed (or period).

Emergency contraception: Oral contraceptive pills that are taken after unprotected sex or contraceptive failure (like a split condom or missing 2 or more hormonal contraceptive pills). Depending on the type of emergency contraceptive you take, it will contain either levonorgestrel (Levonelle 1500, Levonelle One-Step, Generic Levonorgestrel 1.5mg tablets) or ulipristal acetate (ellaOne). 

Endocrine system: All the parts of the body responsible for hormone production and secretion.

Endocrinology: The study of hormones! Scientists who study hormones are termed ‘endocrinologists’.

Endometriosis: A condition when the lining of the uterus (endometrium) starts to grow outside of the uterus. It can cause symptoms of severe cramping (which is usually worse during your period), pain during and after sex, nausea, constipation, very heavy menstrual bleeding and problems with fertility.

Estrogen: A group of steroid hormones. Three main types of estrogen are naturally produced in the body. These are estradiol, estriol, and estrone. Estrogens are produced in the ovaries and adrenal glands. They have many important roles, including kicking off puberty, regulating the menstrual cycle, supporting pregnancy, maintaining bone strength and development, and regulating libido (sexual desire).

Follicle Stimulating Hormone (FSH): A hormone responsible for sexual reproduction and development. It is produced in the pituitary gland (a small gland in the brain). In women, it helps to regulate the menstrual cycle and causes follicles (small fluid sacs that hold eggs in our ovaries) to develop into mature eggs.

Hirsutism: A specific pattern of ‘unwanted hair growth’ on either the face, back, or chest. It may signify an underlying hormonal imbalance due to an excess of androgen hormones, like testosterone.

Hormonal acne: Certain hormone fluctuations (like lower levels of estrogen or higher levels of testosterone) can cause the glands in the skin to produce oil. This triggers acne to ‘flare up’ around your period. You can tell if your acne is linked to your hormones as it often mirrors the oil production patterns of the skin.

Hormone disorder: A condition caused by too little, or too much, of certain hormones. Some examples are polycystic ovary syndrome (PCOS) and hirsutism (unwanted hair growth). Even though our hormone levels change all the time; sometimes these levels lie outside of their normal range and this can have serious effects on the body.

Hormone Imbalance: When an individual has too little, or too much, of a certain hormone. Even though our hormone levels change all the time; sometimes these levels lie outside of their normal range and this can have serious effects on the body.

Hormone: Little chemical messengers which are made in the endocrine system (a collection of glands) and are then released into the blood to be transported to another part of the body. They control cells, tissues, and organs by telling them what to do.

Libido: You may hear this term a lot—essentially a fancy way of saying ‘sex drive’. Your desire to have sex is affected by many hormones including estrogen and testosterone.

Luteinizing Hormone (LH): A hormone responsible for sexual reproduction and development. It is produced in the pituitary gland (a small gland in the brain). In women, it helps to regulate the menstrual cycle and triggers the release of a mature egg from the ovary (ovulation).

Male Condom: A barrier method of contraception consisting of a sheath, or lining, which is worn over the penis during sex.

Menopause: A point in life when your ovaries stop releasing eggs and you no longer experience menstrual bleeds (periods). This usually happens between the ages of 45 and 55 and is caused by a gradual reduction in the production of estrogen from the ovaries. Menopause is reached when you have not had a period for 12 consecutive months.

Menorrhagia: Excessive menstrual bleeding (80mL or more) which lasts for 7 days or more, every 24 to 35 days. Experiencing heavy menstrual bleeding regularly may interfere with your physical and social quality of life as well as your emotional wellbeing.

Menstrual Cycle: This is the monthly hormonal cycle that prepares a woman for a potential pregnancy. It is split into 4 phases: menstruation (your period), the follicular phase, ovulation, and the luteal phase. Transitions into these different phases are controlled by the hormones estrogen, progesterone, Follicle Stimulating Hormone (FSH), and Luteinizing Hormone (LH).

Menstruation: The phase of the menstrual cycle when you have your monthly bleed (period). If you’re not pregnant, you’ll have a period. This is when the lining of your uterus shreds after thickening and building up to prepare for the implantation of a fertilized egg (and a potential pregnancy).

Natural Family Planning: Natural family planning, also known as ‘Fertility Awareness Methods (FAM)’, involves planning sex around your natural fertility cycles. Your natural fertility chart can be created by tracking the length of your menstrual cycle, collecting daily body temperature readings and monitoring changes in your cervical secretions.

Perimenopause: This term means ‘around menopause’. Perimenopause is when a woman’s estrogen levels begin to fluctuate unevenly triggering the transition into menopause (when ovulation will eventually stop completely).

Period: You’ll have your period, or monthly bleed, in the phase of the menstrual cycle known as ‘menstruation.’ You enter the ‘menstruation’ phase if you’re not pregnant. This is when the lining of your uterus shreds after thickening and building up to prepare for a potential pregnancy.

Polycystic Ovary Syndrome (PCOS): A hormonal imbalance condition usually caused by excess androgen production (i.e. too much testosterone). Excess androgens cause some of the main PCOS symptoms, such as unwanted hair growth (hirsutism), male-pattern baldness (adrenal hyperplasia), and acne. Other symptoms include irregular, or no periods (amenorrhea), and difficulty getting pregnant (often due to anovulation).

Premenstrual Dysphoric Disorder (PMDD): Like a more severe form of PMS that is also linked to cyclical hormone level changes (just before your period). The difference between PMS and PMDD is that the emotional symptoms of PMDD are much more extreme. Feelings of anxiety, sadness, or irritability are intensified and may interfere with an individual’s personal, social and professional life.

Premenstrual Syndrome (PMS): A group of cyclical symptoms you may experience before your period due to changes in your hormone levels. Common PMS symptoms include headaches, nausea, tiredness, breast tenderness, mood changes (e.g. feeling low, irritable), abdominal pain, and bloating.

Primary amenorrhea: When a woman hasn’t started her period by the time she is 15 years old.  Even though most young women start their period by the age of 15, it is important to recognise that each individual is different. Some people may start their period later than others.

Primary dysmenorrhea: When you experience pain and/or cramping during or around the time of your menstrual bleed (or period). Primary dysmenorrhea is usually caused by molecules called prostaglandins which are produced in the uterus causing muscular contractions and pain.

Progestogens: The umbrella term used to describe all 'progestational agents - fancy term, we know. These include progesterone, which is the natural progestogen produced in the body, and progestins, the synthetic progestogens found in hormonal contraceptives.

Progesterone-Only Pill (POP): Birth control pills that contain progestogen but not estrogen. They thicken your cervical mucus (making it difficult for sperm to swim through) and decrease the production of LH in the middle of your cycle (which can prevent ovulation). You may be prescribed POPs if you cannot take estrogen-containing contraceptives (if you are over the age of 35, you smoke, or if you have certain medical conditions like migraines with aura, or blood circulation problems). Also, certain medicines such as drugs for treating epilepsy, or antibiotics used to treat tuberculosis and meningitis, may reduce the effectiveness of estrogen-containing contraceptives.

Progesterone: The natural progestogen produced in your ovaries. In women, progesterone has many important roles, including regulating the menstrual cycle, maintaining the early stages of pregnancy, and regulating libido (sexual desire).

Progestin: A synthetic version of your natural progestogen hormone, progesterone. Progestins are used in hormonal contraceptives to replicate the effects of naturally occurring progesterone.

Progestogen-only Implant: A small, flexible rod that is placed just under your skin in your upper arm. The implant continually releases a dose of progestogen into your blood, every 24 hours, for up to 3 years.

Progestogen-only Injection: The injection contains a dose of progestogen, which is injected into the blood every 8-12 weeks (the frequency of injections you need for the injection to be an effective contraceptive depends on the type you are given).

Progestogen-only IUD: Also known as the ‘hormonal IUD’. It’s inserted into your uterus by a healthcare professional where it continually releases a dose of progestogen, every 24 hours, for up to 3 or 5 years (depending on the type of IUD you have inserted).

Regimen: Hormonal contraceptive leaflets often provide instructions on how to follow a particular ‘cycle’ or regimen. Essentially this is just a repeated method of how you should take the contraception provided. For example, some combined oral contraceptives (COC) have a 21/7 (or standard) regimen. This means you take 21 hormone pills and 7 hormone-free (or no pills) in every cycle. Another example is the progestogen-only injection (e.g. Depo-Provera), where each shot lasts for 13 weeks, meaning the cycle length is 13 weeks.

Secondary amenorrhea: When you do not have a natural period for 3 consecutive months (or more), after previously having regular periods, or when you do not have a natural period for 6 consecutive months (or more), after previously having irregular periods. Secondary amenorrhea can be caused by a combination of different factors such as stress, extreme exercise, low or high body weight and genetic disorders, like Turner syndrome.

Secondary dysmenorrhea: When you experience pain and/or cramping during or around the time of your menstrual bleed (or period). Secondary dysmenorrhea is usually caused by an underlying condition such as endometriosis or pelvic inflammatory disease (PID). Insertion of an intrauterine device (IUD) may also cause secondary dysmenorrhea.

Serotonin: You may be more familiar with the term ‘the happy hormone’. Well, this is serotonin. Serotonin regulates your mood and is associated with feelings of happiness and contentment. It also has an important role in the sleep cycle and aids digestion.

Spermicide: A contraceptive gel containing a chemical called nonoxynol-9. Nonoxynol-9 kills sperm and prevents it from entering the uterus. It is commonly used with barrier methods of contraception such as diaphragms and cervical caps.

Testosterone: A hormone responsible for sexual function and development, produced in the ovaries and the adrenal glands. In women, it enhances libido (sexual desire), maintains muscle & bone strength, improves metabolic function, and enhances mood.

The female condom (Femidom): A barrier method of contraception consisting of a thin plastic lining that is worn inside the vagina during sex.

Written by

Hannah Durrant (she/her)

Hannah is a Biomedical Content Writer at Tuune, with a BSc in Biomedical Sciences from University College London. She is passionate about bringing together the scientific community and the general public by disseminating modern science via digestible, engaging and thought-provoking content.

Medically reviewed by

Dr. Arushee Prasad, GP, MBBS (she/her)

Dr Arushee Prasad is a GP for NHS England with an MBBS in Medicine and Surgery, and an MRCGP from the Royal College of General Practitioners. Passionate about digital health and algorithmic medicine, Arushee was previously an Algorithmic Medical Doctor for Docly.