Aloe vera contains a compound named aloenin that promotes hair growth and can help thicken eyebrows.
Just peel off the outer leaf of the aloe and scoop the gel out. Massage the gel into your eyebrows until it gets absorbed. Keep it on for at least 30/40 minutes.
Vitamin E oil promotes hair growth and strengthens damaged hair. It contains several antioxidants and helps solve many of the issues that may be restricting hair growth. To use, just open the vitamin E capsule and apply the oil on your eyebrows. Massage for a few minutes and leave it on overnight.
For decades, curry leaves have been used in Ayurveda to promote hair growth. All you need to do is soak a couple of curry leaves in warm water for a few hours, strain and apply the liquid to your eyebrows.
Studies have shown that hibiscus extract promotes hair growth. Both the flower and the leaves will work well. Just crush the flowers of leaves and apply directly to your eyebrows. Leave on for 30 minutes and rinse with warm water.
You may also like this article about 3 natural oils to increase the thickness of your eyebrows!