# Do supplements interact with hormonal contraceptives?

Source: https://www.healthnews24.co.za/answers/do-supplements-interact-with-the-pill/
Publisher: Healthnews24 (South Africa's supplement answer desk)
Updated: 2026-10-27

> Most common sports supplements, such as whey, creatine, collagen and vitamin D, are not known to interfere with hormonal contraceptives, but St John's wort can make them less effective. Combined pills also slow caffeine clearance, so pre-workouts can feel stronger. Ask a pharmacist before combining any herbal or multi-ingredient product with contraception, and use condoms if advised.

Key facts:
- St John's wort is the best-known supplement that can make hormonal contraceptives less effective.
- UK NHS pharmacy guidance: with a short course of an enzyme inducer such as St John's wort, condoms during use and for at least 28 days after stopping are one option.
- Whey, creatine, collagen, vitamin D and omega-3 have no established interaction with hormonal contraception.
- Combined oral contraceptives slow caffeine clearance, so pre-workouts can feel stronger and last longer.
- Unregistered Category D products in South Africa carry a SAHPRA disclaimer; it is not a safety clearance.

## Do supplements interact with hormonal contraceptives?

A few do, and the important one is **St John's wort**. It speeds up liver enzymes that break down contraceptive hormones, which can lower hormone levels and reduce protection. For short courses of an enzyme inducer, UK NHS pharmacy guidance gives condoms during use and for at least 28 days after stopping as one option; longer use needs a different contraceptive plan. Because the product is sold as a herbal remedy, people forget it counts.

## Which supplements are not a concern?

For the products most South African gym-goers use, there is no established interaction with the pill, patch, ring, injection or implant:

- whey, casein and plant proteins
- creatine monohydrate
- collagen
- vitamin D, vitamin C at normal doses, omega-3, zinc
- electrolytes and carbohydrate gels

Evidence on hormonal contraceptives slightly lowering blood levels of some nutrients (such as B vitamins or magnesium) exists, but its practical importance is unclear and is not a reason to avoid contraception.

## What about caffeine and pre-workouts?

Combined oral contraceptives slow caffeine clearance noticeably, so the same coffee or pre-workout dose lasts longer and feels stronger, which can add to jitters or disturb sleep. If you use stimulant products, start with half a scoop. See [how much caffeine is in pre-workout](/answers/how-much-caffeine-in-pre-workout-south-africa/).

## Which products need a pharmacist's check?

- **Herbal and adaptogen products:** St John's wort, and others with limited interaction data. Check [is ashwagandha safe](/answers/is-ashwagandha-safe-south-africa/) before adding it.
- **Multi-ingredient fat burners and "testosterone boosters":** poorly defined contents and high stimulant loads.
- **High-dose magnesium or any product causing persistent severe diarrhoea or vomiting:** if illness stops tablets being absorbed, follow your contraceptive leaflet and use backup protection as it advises.
- **Anything with an unclear ingredient list.** In South Africa, complementary medicines in the health-supplement category are licensed at business level, and unregistered ones must carry a disclaimer that SAHPRA has not evaluated them. That is not a safety clearance.

## How can you check safely?

1. Take a photo of every supplement label with your contraceptive packaging when you visit a Dis-Chem or Clicks pharmacist or your clinic.
2. Ask specifically about "enzyme induction" and "contraceptive effectiveness".
3. Report any breakthrough bleeding after starting a new product to your clinician.
4. If you must take an interacting product for a short period, agree a backup method and how long to continue it afterwards.

## When should you speak to a doctor?

Speak to your doctor or pharmacist before combining contraception with prescription medicines such as some antiepileptics or antiretrovirals, which can interact far more strongly than supplements. If you are using a supplement for PCOS or period symptoms, see [which supplements have evidence for PCOS](/answers/pcos-supplements-what-has-evidence/). This is general information, not personal medical advice.

If you might be pregnant, are under 18 or have kidney or liver disease, raise that with the pharmacist too.

## Sources

- [NHS Specialist Pharmacy Service: Using contraception with enzyme-inducing medicines](https://sps.nhs.uk/articles/using-contraception-with-enzyme-inducing-medicines)
- [SAHPRA Guideline 7.04: Complementary Medicines, Health Supplements safety and efficacy (Mar 2022)](https://www.sahpra.org.za/wp-content/uploads/2022/03/7.04_CM_SE_Health_Supplements_Mar22_v4_3.pdf)