Try following way: <pre> public function __construct( \Magento\Catalog\Api\ProductRepositoryInterface $productRepository, \Magento\Catalog\Model\Product $product, \Magento\Framework\Registry $registry ) { $this->productRepository = $productRepository; $this->product = $product; $this->registry = $registry; } </pre> Now <pre> $this->registry->register('isSecureArea', true); $product = $this->product->load(1); $existingMediaGalleryEntries = $product->getMediaGalleryEntries(); foreach ($existingMediaGalleryEntries as $key => $entry) { $entry->setLabel('BlahBlah'); } $product->setMediaGalleryEntries($existingMediaGalleryEntries); $this->productRepository->save($product); </pre>