How to Apply Your HYDROGENYX Promo Code at Checkout

Activating a HYDROGENYX promo code takes 15 seconds at checkout — provided it's entered in the right place, at the right time. This guide shows you the exact procedure on desktop and mobile, current codes, and how to combine free delivery + promo. No treasure hunt: all our codes communicated via Klaviyo email or blog article are valid and active. Read for 2 min, save up to €60 on your order.

Prerequisites

• Hardware: web browser or Shopify Shop app.
• Promo code: received via Klaviyo email or HYDROGENYX blog article.
• Time: 15 seconds at checkout.

1. Step-by-step method — Promo code activation

Step 1 — Add ELITE 9K to cart

On the ELITE 9K page, click "Add to cart". The side cart (cart drawer) opens automatically.

Step 2 — Enter the code in the cart drawer (shortcut)

In the cart drawer, below the "Checkout" button, a "Promo code" field is visible. Enter the code in CAPITALS without spaces (e.g. BRAINFOG15). Click "Apply". The discount will be displayed immediately.

Step 3 — Or proceed directly to checkout

If you prefer: click "Checkout". On the Shopify checkout page:

• Desktop: "Discount code or gift card" field at the top right. Enter + Apply.
• Mobile: tap "Show order summary" at the top, then "Discount code or gift card". Enter + Apply.

Step 4 — Check the discount

The "Discount" line appears in the summary with the deducted amount. Example: ELITE 9K at €399 + BRAINFOG15 (-15%) = -€59.85 → total €339.15.

Step 5 — Combined with free shipping

All our codes are combinable with free France Standard Colissimo Tracked delivery (6-10 days). Express Colissimo Signed remains €10.99. If total > threshold, the algorithm applies the optimal priority.

2. Common errors

Error n°1 — Entering the code with spaces or in lowercase. Our codes are case-sensitive. "brainfog15" does not work, "BRAINFOG15" does. Copy-pasting from the Klaviyo email is recommended.

Error n°2 — Attempting 2 codes on the same order. Shopify only allows 1 code per order. If you have 2 valid codes, choose the most advantageous or split into 2 orders.

Error n°3 — Expired code. All our codes have a default validity of 60 days. The expiration date is in the Klaviyo email that sent it to you.

Error n°4 — Attempting to apply after payment. Impossible. Once payment is validated, no code adjustment is possible. If forgotten: contact our support within 24 hours via the contact form to obtain a credit certificate.

Error n°5 — Code not officially communicated. Beware of codes circulating on third-party sites (coupon.fr, etc.): 80% are expired or invalid. Our official codes come only from our Klaviyo email, blog articles, or Le Cercle.

3. FAQ — Your 5 frequently asked questions

Q1. What are the active codes today?
Current codes are communicated via a bi-weekly Klaviyo newsletter. Subscribe in the site footer (immediate -10% welcome discount).

Q2. Does the WELCOME10 code work site-wide?
Yes, -10% on the entire catalog, valid for 30 days after newsletter subscription. 1 use/customer.

Q3. Can I combine a promo code + Cercle discount?
No. Cercle discounts (Tier 1 / 2 / 3) are automatically applied and exclusive of a public promo code.

Q4. What if the code doesn't apply?
Check: exact case, no spaces, validity date, cart > minimum if required. If all is good: contact our support via the contact form (response < 4 business hours).

Q5. Do codes work on the Shopify Shop mobile app?
Yes. "Promo code" field available before payment validation, same flow as desktop.

Upgrade to ELITE 9K — Benefit from your active promo codes

The ELITE 9K HYDROGENYX is eligible for all our promo codes. 9,000 PPB of DPD-validated molecular hydrogen, SPE/PEM platinum-titanium cell, 5-year warranty, 60-day satisfaction guarantee. Lyon 7th workshop, France delivery 6-10 days Colissimo Tracked free.

Discover ELITE 9K →

Paul Fournier, founder of HYDROGENYX. Lyon 7th workshop. 320+ peer-reviewed studies referenced on molecular hydrogen. 1,988 verified reviews 4.7/5. The Source — HYDROGENYX Journal.