Does this product firm sagging skin on the neck
It is unlikely to have a truly noticeable effect, but it could help somewhat improve elasticity. Something with a retinoid (if you could tolerate it) would be a more effective choice - e.g. https://whatsinmyjar.com/product/dr-different-vitalift-a-eye-neck, https://whatsinmyjar.com/product/glowbiotics-md-neck-cessity-anti-ageing-neck-and-decolletage-treatment or https://whatsinmyjar.com/product/cerave-skin-renewing-retinol-face-cream-serum-for-fine-lines-and-wrinkles
It is unlikely to have a truly noticeable effect, but it could help somewhat improve elasticity. Something with a retinoid (if you could tolerate it) would be a more effective choice - e.g. https://whatsinmyjar.com/product/dr-different-vitalift-a-eye-neck, https://whatsinmyjar.com/product/glowbiotics-md-neck-cessity-anti-ageing-neck-and-decolletage-treatment or https://whatsinmyjar.com/product/cerave-skin-renewing-retinol-face-cream-serum-for-fine-lines-and-wrinkles