• Sea Theory ST¹

    Stronger, healthier hair starts within.

    Daily hair growth supplements formulated with Irish seaweed bioactives, biotin, zinc, selenium and vitamins C + D.

    Choose your routine

    30-day money back guarantee

Hair Growth Supplements

Three advanced components in one daily capsule.

ST¹ combines Maragen™ seaweed bioactives with targeted micronutrients and L-Cystine to support healthy hair from within.

  • 01 Maragen™
    Irish seaweed bioactive
  • 02 Micronutrients
    Biotin, Zinc, Selenium, Vitamins C + D
  • 03 L-Cystine
    Amino acid
Inside-Out Hair Health

One capsule a day, delivering marine bioactives and essential nutrients to support healthy hair from within.

Inside-Out Hair Health

ST¹ combines Maragen™ with targeted micronutrients to support the biological processes involved in healthy hair formation, strength and quality.

Learn More
Cellular Research & Evidence

What is ST¹?

ST¹ is formulated with Maragen™ our proprietary marine bioactive complex derived from Irish seaweed. In dermal papilla cell studies, it influenced key markers associated with the hair growth cycles. 

Maragen™ is Sea Theory’s proprietary marine complex of fucoidan-rich seaweed bioactives.

ST¹ Hair Growth Supplements

Growth

Cell proliferation

Associated with the hair follicle’s active growth phase

Strength

GAG production

Molecules involved in hair follicle structure & signaling

Health

Alkaline phosphatase activity

Associated with anagen, the active growth phase of the hair cycle.

The science behind ST¹
Your Hair

What’s changing in your hair?

Thinning

Hair looking or feeling less full.

Shorter growth phases and changes in follicle structure can gradually reduce hair thickness and density.

Shedding

Seeing more hair in your brush or shower?

Shedding increases when more follicles move out of the active growth phase and into the resting and shedding phases.

Hairline + Density

Noticing changes to your hairline?

Changes in follicle activity, anchorage and hair thickness can make the hairline, parting or crown look less dense over time.

ST¹ Hair Growth Supplements

Choose your routine.

Recommended routine

90-day routine

3 jars · 90 capsules · €1.10 /day

€99

€117

Three months of ST¹. No subscription.

Save €18

Best on-going value

Monthly auto-refill

1 jar · 30 capsules · € 0.97 /day

€29 /month

€39/month

Free delivery. Pause or cancel anytime.

Save €10 every month

One-off purchase

30-day supply

1 jar – 30 capsules – €1.30 /day

€39

A simple way to start ST¹

Choose 90 days

Free delivery – no subscription

Start Auto refill

Free delivery – pause or cancel anytime

Choose 30 days

Shipping calculated at checkout

30-day money-back guarantee

Consistency over time

Your 90-day hair routine

Hair changes gradually. ST¹ hair growth supplements are designed for daily use, with one capsule a day as part of a consistent routine.

Month 1

Build the habit

Take ST¹ daily and establish your baseline. Take videos & photos

Month 2

Stay consistent

Hair follows a natural growth cycle, so consistency matters.

Month 3+

Review your progress

Compare how your hair looks and feels with where you started. Take more photos.

Beyond Hair

Daily support from within

ST¹ hair growth supplements are paired with micronutrients that also support your normal immune function, protect cells from oxidative stress and help maintain normal hair.

Questions before you start?

Everything you need to know about taking ST¹ hair growth supplements, the 90-day routine and who it’s for.

30-day money-back guarantee

Hair changes gradually and everyone is different. ST¹ is designed for consistent daily use, so we recommend tracking your experience over 90 days rather than expecting a change at a fixed week.

ST¹ is for adults looking to support normal hair health, strength and quality from within. It is not suitable for anyone under 18. Please consult your dermatologist or doctor if you have more questions.

Hair follows a natural growth cycle, so consistency matters. Ninety days gives you a meaningful period to build a daily routine and review how your hair looks and feels over time.

If you take medication, use other supplements, have a medical condition, or are pregnant or breastfeeding, speak to your doctor before taking ST¹. 

Take one capsule daily with water, with or without food. Do not exceed the recommended daily dose. 

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