Letter of Authorization (LoA) for Thailand Medical Device Registration

1. Key takeaways

A Letter of Authorization (LoA) is a mandatory document for medical device registration in Thailand, and it applies to every risk class without exception, from Class 1 through Class 4. The overseas manufacturer, acting in the role of the Product Owner, must use the LoA to authorise a locally licensed Thai entity to file the application on its behalf, to hold the registration certificate, and to carry the obligations that continue after the product reaches the market. Because the LoA is the instrument that connects the foreign Product Owner to the Thai licence holder, the way it is drafted determines how much control the manufacturer retains over its own product line in Thailand.

• The LoA appears in the document list of every class, so no product, however low its risk classification, can be registered without one.
• The authorised scope should cover filing, licence holding, import, and post-market obligations, including vigilance, recalls, change notifications, renewals, and advertising applications. A scope that mentions only the registration application will cause every later step to stall one by one.
• The product list inside the LoA must be stated model by model, and each model must match the CSDT dossier, the labelling, and the commercial invoices exactly, because the LPI stage checks the models one by one.
• The authorisation term must be long enough to cover the review cycle with room to spare, and it should connect smoothly with the renewal cycle.
• The Product Owner and manufacturer information in the LoA must be fully consistent with the name and address shown in the ISO 13485 certificate and in the CSDT dossier.
• Thailand requires that the licence holder, the importer, and the authorised representative be the same entity, and the LoA is the document that locks in this structure.

2. Legal basis

Two authorisation documents appear in Thai dossiers and they must not be confused. The LoA, or Letter of Authorization, is the instrument by which the Product Owner authorises the Thai licensed entity to file the application and to hold the registration certificate; it is a compliance document that faces the Thai FDA. The PoA, or Power of Attorney, is typically used to authorise the handling of specific administrative acts, such as submitting papers, paying official fees, and collecting the certificate; it is an authorisation document that serves administrative procedures and commercial arrangements. In practice, the mandatory item in the product registration dossier is the LoA, while the PoA is issued separately depending on the licence-holding arrangement and internal processes.

The statutory frame sits in the Medical Device Act B.E. 2551 (2008), which contains the provisions governing the Product Owner and the holding of the licence. The Thai FDA website publishes the Class 1 document list and the Class 2-4 document list, and both lists include the LoA as a mandatory item for every class. The Thai FDA website FAQ, at question 2, confirms that a foreign entity must appoint a Thai local authorised representative. The transfer announcement issued by the Thai FDA on 2024-09-19 requires a consent letter from the original licence holder for any transfer, and the NSW and LPI stages apply model-by-model checking rules to the declared product list.

Because the licence holder, the importer, and the authorised representative must be the same entity, the choice of who holds the licence is also a commercial decision expressed through the LoA. If the licence is held by the distributor, the LoA is issued directly to that distributor, and changing distributors later requires a formal Transfer, which must be supported by a consent letter from the original licence holder. If the licence is held by an Independent Licence Holder (ILH), the LoA is issued to the ILH, and the ILH then supplies the downstream distributors; changing a distributor in this model only requires changing the supply relationship, and the registration certificate is not touched.

3. Expert insights

The single most important drafting decision for Thailand is not the clinical evidence or the quality system certificate, but the breadth of the LoA. Teams that treat the LoA as a mere submission paper, and let the local agent draft it for immediate signature, routinely discover the cost of that shortcut later. When the scope of authorisation is written narrowly, every subsequent distributor change, every variation, and every recall response forces the manufacturer to go back to the original document, obtain new corporate signatures, and re-execute paperwork before anything can move. Experienced regulatory professionals describe the LoA as a commercial control document rather than a registration attachment, because it defines who may act for the Product Owner in the Thai market and to what extent. The recommended discipline is to have the manufacturer’s regulatory function and legal function finalise the text together, and to resist any pressure to sign an agent-drafted version without review. This one file determines how much initiative the manufacturer keeps in the Thai market over the following three years, which is the practical horizon that matters for licence renewals and market changes. Distributor disputes, product-line transfers, and post-market incidents all run through this document, and none of them can wait for a slow re-signing cycle once an urgent situation has already begun.

4. Practical recommendations

• Define the authorised scope so that it expressly covers filing, licence holding, import, and post-market duties, namely vigilance, recall, change notifications, renewal, and advertising applications, instead of limiting it to the registration application.
• List every model individually, and reconcile the model list line by line against the CSDT dossier, the labelling, and the commercial invoices before signing, since the LPI stage checks each model.
• Set the authorisation term so it covers the full review cycle with margin, and align its expiry with the renewal cycle so the two do not fall out of step.
• Check that the Product Owner and manufacturer names and addresses match the ISO 13485 certificate and the CSDT dossier character for character, including legal-entity suffixes.
• Decide the licence-holding model before the LoA is signed: a distributor-held licence makes future distributor changes depend on a Transfer with the original holder’s consent letter, while an ILH keeps distributor changes free of any change to the certificate.
• Have the manufacturer’s regulatory and legal teams finalise the LoA text, and do not hand the drafting to the agent and sign without review.

5. Verification checklist

• □ Verification basis date: 26 October 2026.
• □ Class 1 and Class 2-4 document lists on the Thai FDA website, confirming that the LoA is a mandatory item for every class.
• □ Thai FDA website FAQ, question 2, confirming that a foreign entity must appoint a Thai local authorised representative.
• □ Thai FDA transfer announcement dated 2024-09-19, requiring a consent letter from the original licence holder.
• □ Thai FDA NSW/LPI stage rules on model-by-model checking.
• □ Medical Device Act B.E. 2551 (2008), the provisions relating to the Product Owner and licence holding.

How GRZAN can help. GRZAN provides medical device and IVD registration, quality system, authorised representative and local testing support across Southeast Asia, including Thailand. Our team prepares dossiers to ASEAN CSDT structure, manages submissions and deficiency responses with the Thai FDA, and supports post-market vigilance obligations. Business enquiries: info@grzanglobal.com