Challenges › Seed Cycling Sync
28-day challenge
Seed Cycling Sync
Four seeds, two phases, 28 days. Glowcast works out which seeds are up and checks your meals for them.
On iPhone: $4.99 a week, $14.99 a month or $69.99 a year, with a 7-day trial on the yearly plan.
the rule:
Flax and pumpkin seeds for days 1 to 14, then sesame and sunflower seeds for days 15 to 28.
Glowcast counts from the day you start and tells you which seeds are up.
- flax seeds
- pumpkin seeds
- sesame seeds
- sunflower seeds
- Length
- 28 days
- Level
- Advanced
- You count
- Seeds for the phase
What counts in each phase?
Any of these, in any meal, on the right days. Here's what Glowcast looks for.
Days 1 to 14
flaxseed, ground flax, pumpkin seeds, pepitas
Days 15 to 28
sesame seeds, tahini, sunflower seeds
What's good about seed cycling?
The seeds are the good part: flax, pumpkin, sesame and sunflower all bring real nutrition. Timing them to your cycle hasn't been proven, so treat these four weeks as a fun experiment.
the nerdy bit
The seeds bring real nutrition. Flaxseed is a rich source of fibre and of alpha-linolenic acid (ALA), an omega-3 fat (Parikh et al., 2019). Pumpkin seeds provide minerals such as magnesium and zinc (Kassa and Teferi, 2026). Sunflower seeds are a rich source of vitamin E, with 7.4 mg in an ounce of dry-roasted kernels (Linus Pauling Institute). Flax also has its own skin research: in one trial, flax oil supplements, not whole seeds, cut water loss through the skin by about 10% in 6 weeks (De Spirt et al., 2009).
The cycling itself is unproven: a PubMed search for "seed cycling" turned up 8 records and none set out to test skin (PubMed search, Sep 2026), and a 2025 review of 10 small studies in women with premenstrual syndrome (PMS) or polycystic ovary syndrome (PCOS) said the results so far rest on "small sample sizes and moderate-quality evidence" (Nagarajan et al., 2025).
steal this
Day 1 ideas
Breakfast
Overnight oats with ground flax stirred in
Lunch
Salad with pumpkin seeds
Snack
Seed bliss balls
flax or pumpkin, any meal ✓
the other 3 weeks?
Weeks 2 to 4 unlock in the app
- Week 1done ✓
- Week 2
- Week 3
- Week 4
- badge at the end
- Glowcast counts your days and checks your seeds
- Your streak and progress ring, day by day
- 115 glow recipes for when you're stuck
Quick questions
Do I need to know my cycle?
No. Glowcast counts from the day you start the challenge.
What if my cycle isn't 28 days?
The challenge runs on a 28-day estimate from your start date, so it may not line up with your real cycle.
What if I miss a day?
Your streak resets and the challenge keeps going, but the badge needs every day, so a missed day means no badge this time.
Is this medical advice?
No. If your cycle or hormones worry you, talk to a doctor.
Food inspo, not medical advice.
Sources
- Parikh M, Maddaford TG, Austria JA, et al. Dietary flaxseed as a strategy for improving human health. Nutrients. 2019. pubmed.ncbi.nlm.nih.gov
- Kassa MG, Teferi DA. Phytochemical composition, health benefits, functional properties, and food applications of pumpkin seeds. Food Sci Nutr. 2026. pubmed.ncbi.nlm.nih.gov
- Linus Pauling Institute, Oregon State University. Vitamin E. Micronutrient Information Center. lpi.oregonstate.edu
- De Spirt S et al. Intervention with flaxseed and borage oil supplements modulates skin condition in women. Br J Nutr. 2009. pubmed.ncbi.nlm.nih.gov
- PubMed. Search results for “seed cycling”, 8 records. Searched 15 Sep 2026. pubmed.ncbi.nlm.nih.gov
- Nagarajan DR, Mani Jacob D, Munir Mufti M, et al. Efficacy of seed cycling as an integrative therapy for premenstrual syndrome and polycystic ovary syndrome in reproductive-aged women: a systematic review. Cureus. 2025. pubmed.ncbi.nlm.nih.gov
