

HSA/FSA Payments Simplified with FLEX
At checkout, select Flex | Pay with HSA/FSA as your payment option. You will be prompted to complete a brief telehealth consult to confirm your eligibility to pay with HSA/FSA. From there, enter your HSA or FSA debit card details and complete your checkout as usual. If you don’t have your HSA or FSA debit card handy, you can also complete the checkout with a regular credit or debit card.
Step-by-Step Checkout Process

1. Add HSA/FSA Eligible Products to Cart

2. Select Flex | Pay with HSA/FSA at Checkout

3. Confirm Eligibility

4. Enter your HSA/FSA Card Details
*HSA/FSA card transactions will not work on Subscription orders at this time. It must be used on a one-time purchase.
Within 24 hours of your purchase, Flex will email you both a Letter of Medical Necessity as well as an itemized receipt.
Keep these documents for your records should your HSA/FSA provider or the IRS require additional documentation.
That’s it! For more information, check out our FAQs below or reach out to customerservice@cellutrex.com.
FAQ
What is an FSA or HSA and what are the benefits?
An FSA (Flexible Spending Account) and an HSA (Health Savings Account) are tax-advantaged accounts for medical expenses but differ in key aspects. FSAs, employer-sponsored, allow employees to use pre-tax dollars for medical expenses such as prescriptions and copays, but typically feature a "use-it-or-lose-it" policy where funds must be used within the plan year. HSAs are available to those with a high-deductible health plan and offer more flexibility, allowing funds to roll over annually.
How can I spend my FSA or HSA funds at Cellutrex®?
Select “Flex | Pay with HSA/FSA'' at checkout. Input your card details and checkout as usual.
Purchase requires verification of eligibility, follow the steps to complete a brief telehealth consult via chat.
I’m not seeing HSA or FSA options show up at checkout. Why not?
In this case, none of the items in your cart may be HSA or FSA eligible. The other reason could be an item in the cart is on a subscription. Unfortunately the HSA/FSA program can only support one-time transactions and not subscription orders. Please reach out to customerservice@cellutrex.com if you think there is an error or if you have any additional questions.
I keep being pushed into Shop Pay. How do I use my HSA/FSA card?
If you continue to be pushed into the ShopPay checkout, we recommend completing your purchase in an incognito window or logging out of Shop Pay.
Why was my HSA or FSA card rejected?
Like any credit or debit card, HSA/FSAs can be declined if any of the data from the card is incorrect (number, expiration date, zip code etc). Flex will alert you in checkout if any of these fields is missing or incorrect so you can update them.
The most common reason for rejection of the card is insufficient funds. Reach out to your HSA or FSA provider to verify the amount of money in your account before attempting to complete your purchase again.
I don’t have an HSA or FSA card. Can I still use my HSA/FSA funds?
Yes, you can still be reimbursed for the expense.
Select “Flex | Pay with HSA/FSA” at checkout. Instead of entering your HSA or FSA card, input your regular credit card.
Flex will email you an itemized receipt following your purchase. Submit the itemized receipt to your HSA or FSA provider for reimbursement.
What is a Letter of Medical Necessity?
ALetter of Medical Necessity(opens in a new tab)(LOMN) is a document written by a healthcare provider that explains why a specific medical service, treatment, or equipment is necessary for a patient's health. In relation to an HSA (Health Savings Account) or FSA (Flexible Spending Account), an LOMN is often required for reimbursement of expenses that are not clearly defined as eligible under the standard IRS guidelines.
Help! I didn't receive an email from Flex with my itemized receipt and/or letter of medical necessity. What should I do?
Please check your spam folder, as sometimes emails from notifications@withflex.com may be automatically filtered as spam by some email service providers. If you still can’t find it, please email support@withflex.com and let them know the email address associated with your order.
Who is Flex and what is their relationship with Cellutrex®?
Flex has partnered with Cellutrex® to enable consumers to use their HSA/FSA funds. You can think of Flex as an alternative to payment method, similar to Affirm, Klarna etc.
I still have more questions on HSA/FSA. Who should I reach out to?
customerservice@cellutrex.com