The best essential oil that works best for me to tighten skin is Frankincense Essential Oil.
I take Frankincense Essential Oil and dilute it in some Olive Oil and then massage the Frankincense Essential Oil into my skin.
It almost immediately reduces the appearance of my saggy skin and tightens the loose saggy skin.
I dilute the Frankincense Essential Oil first because if you don't it can irritate your skin or cause a rash on your skin so diluting the Frankincense Essential Oil is a must.
Other good essential oils that work good for tightening saggy and wrinkly skin are Grapeseed Essential Oil, Lavender Essential Oil, Neroli Essential Oil, Almond Oil and Pomegranate Essential Oils.
Just be sure to always use a carrier oil to dilute those essential oils before applying them to your skin.