Acne is one of the most common skin problems in teenagers and young adults and many also notice their skin gets worse in the days before their period. Both have the same root cause, which is the way hormones affect the oil in your skin.
Why it happens
Your skin has tiny oil glands that make an oily substance called sebum. Hormones called androgens, such as testosterone, make these glands produce more oil. Everyone has some androgens, and levels rise during puberty. When extra oil mixes with dead skin cells, it can block a pore. Bacteria that normally live on your skin can then grow inside the blocked pore, which causes red, swollen spots.
The hormone changes before your period can make your skin oilier, which is why spots often flare at that time.
Treatments with good evidence
These treatments have the best evidence behind them and your doctor may bring them up:
benzoyl peroxide, a cream or wash you can buy at a pharmacy
topical retinoids, creams such as adapalene that help keep pores clear
antibiotic creams, used together with benzoyl peroxide
an antibiotic tablet called doxycycline, for more widespread acne
For acne linked to hormones, a doctor may also suggest the combined pill, or in some cases a tablet called spironolactone. Severe acne or acne that scars may need a stronger tablet called isotretinoin, which is prescribed and monitored by a skin specialist.
Most treatments take 8 to 12 weeks to work, so give one a fair try before deciding it isn't working.
What about food and skincare?
We still don't know much about how food affects acne. High-sugar foods and dairy may play a part for some people, but there isn't enough evidence to tell everyone to cut foods out. Cutting out whole food groups can also leave you short of nutrients. A balanced diet with lots of colourful fruits and vegetables, wholefoods, protein and slow digesting carbohydrates are still foundational from a nutrition perspective.
When acne is part of something else
Acne together with irregular periods or extra hair on your face or body can be a sign of PMOS (fomerly known as polycystic ovary syndrome). It's worth mentioning all of these to a doctor at the same time.
When to see a doctor
pharmacy treatments haven't helped after about three months
you have deep, painful lumps
your acne is leaving scars or dark marks
it's affecting your mood or confidence
you also have irregular periods or extra hair growth
For skincare, keep it simple. Wash with a gentle cleanser, use a moisturiser and sunscreen labelled non-comedogenic (which means it won't block pores), and try not to pick or squeeze. Be wary of complicated routines you see online, as using too many active products at once can irritate your skin.