Amazon's beauty department is a treasure trove of haircare products, especially those designed to keep your tresses thick and long. And as someone who has a history of trichotillomania, I'm constantly on the hunt for hair growth products. But I'm not just looking for any standard hair treatments; I'm in the market for ones with ingredients that are scientifically proven to help.

Given Amazon's expansive selection of products, it's a great place to start. You'll find thousands of options with reviews from verified customers, or you can search for products by ingredient. And here's the best part: Those with Prime accounts (FYI, Amazon offers a free trial) can get hair growth products delivered to their doorsteps in just two days.

Since I'm not versed on the science of skin and hair growth, I turned to three board-certified dermatologists: Dr. Hayley Goldbach, a dermatologic skin cancer surgeon at Brown University, Dr. Audrey Kunin, the founder of Dermadoctor, and Dr. Jeannette Graf, an assistant clinical professor of dermatology at Mount Sinai School of Medicine. And while these dermatologists agree that hair growth products with ingredients like biotin, collagen, and even onion oil can help, it's important to visit a doctor to determine the root cause of hair thinning.

If you want to get your hair in tip-top shape for summer, keep reading to find 10 products from Amazon that might just do the trick — starting at $8:

• Luseta Biotin Hair Growth Serum, $17 (Originally $25)
• Tricho Labs Folliboost Hair Growth Serum, $40
• Mamaearth Onion Oil for Hair Growth, $11 with coupon (Originally $15)
• EarthShine Biotin Hair Growth Oil Revitalizing Serum, $20 with coupon (Originally $22)
• Ultrax Labs Hair Surge Shampoo, $80
• Wild Growth Hair Oil, $9
• Elevate Hair-Growth Oil, $18 (Originally $35)
• CB Smoothe Wild Jamaican Black Castor Oil, $8
• Rogaine 5% Minoxidil Foam, $43
• Kate Blanc Cosmetics Castor Oil, $10

Luseta Biotin Hair-Growth Serum

This Amazon's Choice hair regrowth serum is made with nourishing ingredients like biotin, collagen, argan oil, and sunflower seed oil. "Biotin works to keep the hair moisturized and keeps it from becoming brittle," Dr. Graf said, adding, "Argan oil and sunflower oil help to rebuild damaged hair, which, in turn, aids in the production of new strands." The formula is safe for color-treated hair, and it's free of parabens and sulfates. To use, apply a quarter-sized amount from the roots to the tips of either damp or dry hair, and leave it in for a few minutes so your scalp can soak up all the nutrients.

Shop now: $17 (Originally $25); amazon.com

Tricho Labs Folliboost Hair-Growth Serum

With key ingredients like biotin, pea sprout extract, and peppermint oil, this hair serum "works wonders" for thin hair in a matter of weeks, according to one reviewer. Dr. Goldbach explained there's "promising evidence" that peppermint oil "might help with hair thickness and hair follicle count." Plus, pea sprout extract has been clinically shown to safely promote hair growth. For best results, massage one to three drops of the serum into your scalp twice a day.

Shop now: $40; amazon.com

Mamaearth Onion Oil for Hair Growth

This may come as a surprise, but onion oil is actually a popular ingredient for hair growth. In a clinical study that compared the hair-growth effects of onion juice to tap water in people with alopecia areata (patchy hair loss), the onion oil resulted in significantly more new strands. This specific formula is free of sulfates, parabens, and synthetic fragrances, and it's meant to be left in your hair for two to four hours before washing it out. One reviewer said it leaves their hair feeling "silky soft."

Shop now: $11 with coupon (Originally $15); amazon.com

EarthShine Biotin Hair-Growth Oil Revitalizing Serum

Similar to the products mentioned above, this serum's star ingredient is biotin, which may help stimulate growth by rejuvenating hair follicles. Plus, it's formulated with all hair types in mind, so you can use it whether you have thick, thin, curly, or fine hair. The brand recommends applying the serum to damp hair and massaging it into your scalp for two to three minutes before rinsing out any excess product.

Shop now: $20 with coupon (Originally $22); amazon.com

Ultrax Labs Hair Surge Shampoo

Next time you hop in the shower, you may want to opt for this Amazon's Choice caffeine shampoo. "There is some evidence that caffeine shampoo and lotion can decrease hair shedding," Dr. Goldbach tells InStyle. "This particular product contains saw palmetto, and there have been a few small studies that showed that saw palmetto lotion and serum might help thicken hair." Plus, it will clean your hair without removing the natural oils designed to keep it soft, shiny, and healthy. One happy reviewer called this shampoo a "hair loss miracle."

Shop now: $80; amazon.com

Wild Growth Hair Oil

A key ingredient in this hair oil product is pumpkin seed extract, which contains an ingredient that blocks the hormone DHT and is believed to help support healthy hair growth, according to Dr. Kunin. One reviewer, who massaged the serum into their scalp every night, saw results in just 10 days. And apart from thickening your hair, this serum can also help detangle strands and reduce blow-drying time.

Shop now: $9; amazon.com

Elevate Hair-Growth Oil

This popular hair-growth oil has a high concentration of Minoxidil, which is a "clinically proven over-the-counter medication to help reduce the rate and volume of hair loss," Dr. Kunin said. To use the serum, apply it to damp hair after washing it, or mix it in with your shampoo for a quick, two-in-one experience.

Shop now: $18 (Originally $35); amazon.com

CB Smoothe Wild Jamaican Black Castor Oil

Made without mineral oils, sulfates, and parabens, this castor oil serum is one you can feel comfortable about putting on your strands. It's made with black castor oil, which Dr. Graf said "increases the blood circulation in the scalp, which, in turn, promotes hair growth." According to the brand, it's gentle enough to use every day on your scalp and hair.

Shop now: $8; amazon.com

Rogaine 5% Minoxidil Foam

This topical treatment is made to help reverse hair thinning thanks to its key ingredient, Minoxidil, which "boosts hair follicle activity and hair protein production of the hair," Dr. Graf said. The bottle comes with enough product to last for four months, and it's recommended that you use it once a day for clinically proven results. As one reviewer put it, Rogaine foam is a "miracle in a bottle."

Shop now: $43; amazon.com

Kate Blanc Cosmetics Castor Oil

With over 45,000 five-star ratings from shoppers who say it "works like magic," this $10 hair oil has clearly amassed a major following. The main ingredient in the product is castor oil, which can strengthen locks by "protecting and promoting healthy hair follicles," Dr. Graf said. In addition to applying the oil to your scalp, you can use it on your eyelashes and eyebrows, too, thanks to the handy application tools that come in the package.

Shop now: $10; amazon.com