@ohdarlingitsbiology
Fibromyalgia · PMOS · IBS · Depression · Cluster 2

Gut-Brain & Hormones
Supplement Stack

Evidence-based picks for Fibromyalgia, PMOS (formerly PCOS), IBS, Depression, Anxiety and OCD. Phased for safe introduction.

~£70–90
Full stack / month
10
Supplements · 4 phases
May 2026
Last updated
10/10
Links confirmed ✅
Affiliate disclosure: This page contains Amazon Associates affiliate links. @ohdarlingitsbiology earns from qualifying purchases at no extra cost to you.
Phase 1 · Foundation
One new supplement per week
Weeks 1–4
1
Magnesium Glycinate 3-in-1
DepressionAnxietyFibromyalgiaOCD
Nutrition Geeks Magnesium Glycinate 3-in-1 · 1800mg · 90 vegan caps · UK Made
Cofactor for serotonin and GABA synthesis — essential for depression and anxiety. Reduces cortisol reactivity, calms central sensitisation in fibromyalgia. Glycinate is gentle on digestion and supports sleep. Start here — most important single supplement for this cluster.
2 caps/day · Evening~£10 · 3 months~11p/day
Amazon
2
Vitamin D3 + K2 MK-7
DepressionFibromyalgiaPMOS
Unicorn Brands D3 4000iu + K2 MK7 · 365 tablets · 1-year supply · UK Made · 14,000+ reviews
Deficiency confirmed in depression, fibromyalgia and PMOS. D3 supports serotonin synthesis genes, reduces central sensitisation and improves insulin sensitivity. K2 directs calcium to bones, not soft tissue.
1 tablet/day · With fat~£12 · 12 months~3p/day
Amazon
3
Omega-3 High EPA
DepressionFibromyalgiaIBSPMOS
Nutravita Omega-3 2000mg · 660mg EPA + 440mg DHA · 240 softgels · 4-month supply · 27,000+ reviews
Meta-analyses confirm EPA reduces depression severity. Resolves neuroinflammation, restores gut barrier integrity and reduces central sensitisation driving fibromyalgia pain. High EPA:DHA ratio is the evidence-based target for mood.
2 caps/day · With meal~£14 · 4 months~12p/day
Amazon
Phase 2 · Gut & Hormones
Allow 6–8 weeks for PMOS and IBS effect
Weeks 4–8
4
Multi-Strain Probiotic
IBSOCDDepressionPMOS
Optibac or Bio-Kult · 50B CFU · L. rhamnosus + L. acidophilus + Bifidobacterium
L. rhamnosus reduces OCD-like behaviours and anxiety in RCTs. Restores SCFA production, repairs gut barrier and reduces LPS-driven systemic inflammation. Optibac is the UK clinical standard.
1 cap/day · Morning fasted~£15–20/month~50–65p/day
Amazon
5
Myo-Inositol + D-Chiro (40:1)
PMOSOCDAnxiety
Horbaach Myo-Inositol & D-Chiro Inositol · 90 vegan tablets · 40:1 ratio · 2000mg Myo + 50mg DCI
The single most evidence-backed supplement for PMOS — improves insulin sensitivity, restores ovarian function and reduces androgen excess. RCT evidence also shows reduction in OCD severity. Allow 3–6 months for full hormonal benefit.
2–4 tabs/day · Split with food~£14 · 1–3 months~15–30p/day
Amazon
Phase 3 · Brain & Pain
Targets OCD glutamate & central sensitisation
Weeks 8–12
6
NAC 600mg
OCDFibromyalgiaDepression
Solgar NAC N-Acetyl-L-Cysteine 600mg · 60 vegan vegicaps · Soy-free
RCTs show NAC reduces OCD severity by normalising glutamate levels in the striatum. Also a glutathione precursor — reduces oxidative stress in fibromyalgia and supports gut barrier repair.
1–2 caps/day · With food~£22 · 1–2 months~37p/day
Amazon
7
Ashwagandha KSM-66
AnxietyPMOSFibromyalgia
Nutrition Geeks Ashwagandha KSM-66 3000mg + L-Tryptophan + B6 · 60 vegan caps · 2-month supply · 5,400+ reviews
KSM-66 is the most clinically studied ashwagandha extract. RCTs show significant reduction in cortisol, anxiety scores and perceived stress — directly targeting HPA axis hyperactivation, the upstream driver of insulin resistance and androgen excess.
1 cap/day · Evening~£12 · 2 months~20p/day
Amazon
Phase 4 · Methylation & Insulin
GP check before Berberine
Week 12+
8
Methylated B-Complex
DepressionOCDPMOS
BioCare Methyl B Complex · Quatrefolic 5-MTHF + Adenosyl/Methyl B12 + P-5-P B6 · 60 vegan caps
MTHFR variants impair folate methylation, reducing serotonin and dopamine synthesis. Methylfolate is the most well-evidenced adjunct to antidepressants. Quatrefolic is the gold-standard methylfolate form.
1 cap/day · Morning~£22 · 2 months~37p/day
Amazon
⚠ Start at ¼ dose and build — some people are sensitive to methyl donors.
9
Berberine 500mg
PMOSIBSFibromyalgia
Berberine HCl 500mg · 60–120 vegan capsules · GMP certified · UK or EU made preferred
Activates AMPK — the same pathway as metformin — to reduce insulin resistance, lower androgens and restore cycle regularity in PMOS. Also modulates gut microbiome directly.
500mg x2/day · Before meals~£15–20 · 1–2 months
Amazon
⚠ Must check with GP first — significant drug interactions with statins, diabetes medication, antibiotics and more.
10
Zinc + Selenium + Biotin
PMOSDepressionFibromyalgia
Nutrition Geeks Biotin 10,000mcg + Zinc + Selenium · 180 vegan tablets · 6-month supply · 8,000+ reviews
Zinc inhibits 5-alpha reductase — the enzyme converting testosterone to DHT — the primary androgen driver in PMOS. Selenium is essential for thyroid function. Both commonly depleted in PMOS and depression.
1 tablet/day · With food~£10 · 6 months~6p/day
Amazon
Phase 1 (Weeks 1–4)~£12/mo
+ Phase 2 (Weeks 4–8)+£20/mo
+ Phase 3 (Weeks 8–12)+£18/mo
+ Phase 4 (Week 12+)+£20/mo
Full Stack (10 supplements)~£70–90/mo
⚠ Important: This information is for educational purposes only and does not constitute medical advice. It is not a substitute for professional medical consultation, diagnosis or treatment. Always consult your GP or a qualified healthcare professional before making any changes to your supplement or medication regimen — particularly Berberine (significant drug interactions) and Inositol (if on blood sugar medication). Introduce one supplement per week. Prices approximate as of May 2026.

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