IN & OUT Duo
IN & OUT Duo
IN & OUT Duo

IN & OUT Duo

Your customised IN & OUT duo for healthy nails all year round!

Our IN & OUT routine is tailored to each nail type: two kinds of nail care working in harmony for visible, long-lasting results.

What type of nails do you have? Complete our analysis by clicking here and find out!

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Only 954 items in stock!

IN & OUT Duo

Only 954 items in stock!
Free delivery when you spend €39 or more
Payment in 3 interest free installments
Click & Collect Free collection in 2 hours

Brand highlights

  • Up to 84% bio-sourced ingredients
    Plant-based ingredients extracted from natural, renewable sources
  • Made in France
    Products made in France
  • Vegan
    Our aim is to develop products without using ingredients that come from animals or the farming of animals
  • 12-free
    Green Flash

  • Eco-friendly packaging
    Recyclable packaging, FSC cardboard and biodegradable packing peanuts
  • No toxic ingredients
    Products formulated based on a strict blacklist

Kit content

  • Nail Boost

    Nail Boost

    29 €
  • The treatment base coat of your choice

    The treatment base coat of your choice




IN: Nail Boost food supplements work from the inside to provide your body with everything it needs to synthesise keratin, the main component of nails and hair. A complete formula for strong nails and optimal growth.

OUT: Our treatment base coat works locally to address a particular problem and enhance your nails. Choose the base coat that meets your needs.

May contain traces of gluten.


  • A food supplement developed to meet your need
  • Bio-sourced formulas
  • Recyclable eco-designed packaging
  • This routine can be customised to address any nail issues

How to use Nail Boost food supplements?

As a treatment, take 4 capsules a day (for no more than 3 months).
For maintenance, take 2 capsules a day (for no more than 6 months).
To find out the right dose for you, complete our analysis!

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Procedure We tell you everything!

  1. File your nails into your desired shape
  2. Gently buff each nail for 5 seconds in the direction of growth
  3. Use the cuticle remover and cuticle pusher to push back the cuticles
  1. Apply Green Oil to the surface of the nail
  2. Remove the oil from the surface of the nail with a gentle nail polish remover
  3. Use the treatment base coat to care for and protect your nails

The word of the teaM

"The perfect duo to boost growth and keep your nails healthy"


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FAQ Your questions

Find out the most frequently asked questions for this product

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Yes, we recommend you always apply a base coat under your polish to help the colour adhere and protect the nail from the pigments.

You can apply a layer of treatment base coat before your full Green Flash manicure. However, the treatment base coat does not replace the Green Flash Base Coat.

Yes, the base coat can be removed with Green Nail Polish Remover.

Take a capsule with a glass of water or break it in half and empty the powder into a cold liquid (fruit puree, yoghurt, etc.) as heat will damage the vitamins and minerals.

These food supplements can be taken as a treatment (4 capsules a day) when your nails seem duller and weaker than usual. Take for 3 months for optimal results.
They can also be taken to give your nails an occasional boost when they seem otherwise healthy. In this case, you only need to take 2 capsules a day.

Until the expiry date shown on the product.

We are committed to offering you a complete formula guaranteed to meet 100% of your daily vitamin, mineral and amino acid requirements, recommended for healthy nail growth. Our formula is not chemically concentrated. So you need a specific amount of plant extracts to fully meet your body's needs.

These food supplements are not recommended for pregnant or breastfeeding women, anyone with hyperthyroidism or anyone taking anticoagulants. Long-term use is not recommended; nor is exceeding the recommended dose.

Our supplements contain brewer's yeast from beer wort. Beer wort is obtained from malt and hops. Our supplements may therefore contain traces of gluten. If you are allergic, we recommend you consult your doctor.

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Nail care products


Designed for each step of your manicure, our nail care range includes a cuticle remover to make it easier to work on your cuticles, 4 treatment base coats (one for each type of nail) and a green oil chosen for its nourishing properties.
The result? Long-lasting colour combined with a unique sensory experience!

Our Philosophy

Spotlight on the ingredients

Brewer's yeast

Brewer's yeast is rich in vitamins and minerals to strengthen and regenerate weakened nails.

Bamboo extract

Natural horsetail extract (equisetum arvense extract) is rich in silica to reinforce and enhance nails.

Horsetail extract

Bamboo extract (bambusa vulgaris extract) helps make nails strong and healthy.

Reviews Our customers talk about us!

Our reviews are collected 2 weeks after any purchase and these are the reviews of verified buyers only