The honest answer no one selling supplements wants to give: it depends what symptom you're tracking and which ingredient you're taking.
The fast wins (week 1 to 2)
Some symptoms respond quickly because they're driven by short-term biochemistry.
- Cramps and tension. Magnesium can ease both within the first cycle. You feel the change in week one or two if you're consistent.
- Daytime energy. B vitamins, especially B12 and B6, lift fatigue inside a fortnight if you were deficient.
- Sleep. L-theanine and magnesium together calm the nervous system enough to notice in the first week.
The slower wins (week 4 to 12)
Hormonal balance takes longer because your cycle is long. You need 2 to 3 full cycles for any supplement to show its full effect.
- PMS mood symptoms. Often need 2 full cycles before women notice the worst week feels less worst.
- Skin and breakouts. Cycle-driven acne shifts as oestrogen metabolism catches up. Give it 12 weeks.
- Cycle regularity. This is the slowest. Three to six months of consistent intake before you can judge.
Why two weeks isn't enough
Your cycle has four phases. You haven't been through them all yet. Half the symptoms you're tracking only show up in two of the four phases. The maths doesn't work in 14 days.
The honest expectation
Take it daily. Track three full cycles. Then decide. Anyone promising you a transformation in two weeks is selling you a story, not a supplement.