Using oils for hair growth and thickness is a practice that has been passed down from generation to generation.
In ancient India, oils were religiously used before taking a shower or before bed to harness the restorative properties of natural oils. This helped reduce dryness and strengthen the hair.
Here are some of the best oils that were used for hair growth and thickness.
1. Onion Oil
Onions contain nutrients and bioactive compounds such as Vitamin C, folate, vitamin B6, and potassium that nourish the hair follicles increasing hair volume, and strength.
Onion oil is enriched with dietary sulfur which prevents thinning and breakage of hair and is essential for hair follicles regeneration.
It can strengthen the hair roots thus promoting fast and healthy hair growth.
Here is a more comprehensive article on onion oil and the benefits it has on hair.
2. Argan Oil
Argan oil, commonly known as liquid gold is a natural sunscreen that protects your hair from any sun damage enhancing growth and thickness.
If you are prone to frizzy hair, then argan oil is your best bet as it repairs dry brittle hair stimulating hair growth.
It has been known to work wonders for thinning hair and moisturizes the hair follicles as it easily penetrates the scalp.
3. Bhringraj Oil
Bhringraj oil is well known in Ayurveda, an Indian tradition that seeks to balance and heal the body through nutrition.
Also known as bhangra, this oil has been used for centuries in the treatment of hair loss and alopecia by stimulating the hair follicles. 
It promotes hair growth and prevents premature aging when you massage it on your scalp regularly.
4. Sweet Almond Oil
It is enriched with Vitamins B, A, E, and Omega 9, and 3 fatty acids that keep the hair healthy and strong.
Sweet almond oil is an emollient meaning it will restore the moisture balance of your scalp and hair.
If you have any scalp irritation and dryness, then almond oil will definitely get rid of that enhancing hair growth.
5. Jojoba Oil
Jojoba oil stimulates hair growth by improving blood circulation to the scalp and moisturizing the hair strands.
By repairing dry and damaged hair, it increases hair thickness.
Did you know that jojoba oil mimics the sebum that our scalp produces? Yes it does!
This is because it contains triglycerides which are compatible with natural sebum. This compatibility is an advantage as it balances your scalp’s PH ensuring it is not too dry or greasy. 
Jojoba also contains liquid wax making it a good humectant that creates a protective film on hair preventing moisture loss.
6. Olive Oil
Olive oil contains powerful antioxidants that rid the body of free radicals that poison our cells. The oil also protects the hair follicles encouraging growth and thickness.
It prevents hair loss and stimulates the growth of new hair.
Regular use of olive oil prevents the formation of DTH hormone facilitating hair growth. By inhibiting the absorption of excess moisture it prevents any frizz and hair breakage.
7. Peppermint Oil
We all love the cooling soothing feeling that peppermint oil gives our scalp, don’t we?
Peppermint oil is a stimulant that greatly improves dry hair giving it life.
It cleans and removes any dirt from the hair improving blood circulation to the scalp and enhancing the growth of hair. For those with an oily scalp, peppermint oil will balance the oily effects.
8. Lavender Oil
Lavender oil is considered one of the most effective treatments for hair growth.  It has also been used to treat Alopecia, a condition that causes excessive hair loss.
In addition, Lavender oil also anti-microbial properties that fight viruses, micro-organisms, and fungi on your scalp thus promoting a healthy scalp.
9. Black Castor Oil
Tired of split ends and hair breakage? Black castor oil works well on any hair loss issues encouraging the growth of voluminous, healthy hair.
It also helps eradicate any dandruff and toxins on the scalp stimulating growth and hair thickness.
10. Coconut Oil
Coconut oil promotes hair growth and thickness as it is enriched with lauric acid, and Vitamin E and K. It is easily absorbed into the hair cuticles.
This oil helps in retaining moisture in the scalp to prevent hair breakage. Coconut oil protects hair from environmental factors like wind, sun, smoke, and dust.
Enriched with anti-fungal and anti-microbial properties, it helps get rid of any scalp buildup and bacteria, strengthening the hair follicles in the process. You can add coconut oil to your pre-wash regimen for maximum results.
11. Amla Oil
Amla is enriched with Vitamin C and antioxidants that promote healthy hair growth.
It is known to improve hair pigmentation. It has been used for years by Indian women for hair growth treatments.
This oil improves blood circulation to the scalp promoting the growth and thickness of hair. It also dissolves any grease and dirt on the hair strands improving the scalp’s overall health.
12. Avocado Oil
The fats and Vitamin E in avocado oil promote healthy hair which translates to hair growth. Avocado oil prevents hair loss and works well with other carrier oils such as lavender and tea tree oils.
If your hair has any sun damage avocado oil is excellent for restoring moisture to your strands. The Vitamin D in avocado oil helps in the generation of new hair follicles.
13. Palm Kernel Oil
Palm Kernel oil has palmitic acid, lauric acid, oleic acid, and Vitamins A, K, and E which help hair grow faster and thicker.
It also antioxidants that maintain collagen in the hair preventing hair loss. Being light and non-greasy it is perfect for those with curly hair as it easily penetrates the hair roots stimulating growth.
You can use it as a hot-oil treatment where it provides a soothing effect nourishing the hair follicles. Being saturated with fatty acids palm kernel oil strengthens any weak or damaged hair.
14. Grapeseed Oil
Commonly known as grape oil it is made by pressing the seeds used for winemaking. It is a light, thin, colorless and odorless oil enriched with essential fatty acids and antioxidants such as Omega 6 and Vitamin E.
Grapeseed oil is easily absorbed into the scalp deeply moisturizing the scalp to enhance the growth and thickness of hair. This makes it one of the best oils for low porosity hair.
You can use it as a hot-oil treatment to strengthen your hair cuticles. Grape seed oil works magic on any dead skin build-up on the scalp giving way for new hair growth.
Looking to buy any of these oils? Here are our top picks. (Please note these are affiliate links)