Hair Thickening Serum and Scalp Tonic for Thinning Hair: Dr. Groot Leave-In Guide
Want a leave-in step for thinning, fragile hair? Compare Dr. Groot Hair Thickening Roll On Serum, Hair Thickening Tonic and Scalp Barrier Boost Oil in Serum by format, results and scalp type.
Quick answer: Add a leave-in scalp product to your routine when hair looks thinner because strands break easily.
- Hair Thickening Roll On Serum: a roll-on serum for precise spot care. Used in the full Scalp Revitalizing Solution routine, it reduced hair loss due to breakage by 82.2% in 2 weeks.¹
- Hair Thickening Tonic: a spray that covers the whole scalp. Used alone, it reduced hair loss due to breakage by 47.4% in 2 weeks and 69.8% in 4 weeks.²
- Scalp Barrier Boost Oil in Serum: a lightweight antioxidant oil serum for a scalp that needs moisture and protection.
Shampoo and conditioner rinse off within minutes. A leave-in serum or tonic stays on the scalp, so it can keep working between washes. Korean hair care brand Dr. Groot makes three leave-in products for its Scalp Revitalizing Solution line. Each one cares for the scalp and helps hair look thicker and healthier, and each comes in a different format.
Start with the reason your hair looks thinner
If strands snap during brushing or styling, or your scalp feels dry, oily or congested, a scalp serum or tonic can help. Hair loss that starts suddenly, shows up in patches, or comes with pain or sores is different. In those cases, see a dermatologist. Dr. Groot serums and tonics are cosmetic scalp care, so a dermatologist can help you decide whether you need a treatment plan as well.
Dr. Groot Hair Thickening Roll On Serum
This serum treats your scalp with the same care you give your face. A metal roller tip lets you target specific areas, and the watery serum feels refreshing, light and non-sticky.
- Reduces hair loss due to breakage and nourishes the scalp for healthy-looking hair.
- Suits all scalp types and is safe for color-treated hair.
- Works well for thin, damaged or dry hair.
- Formulated without parabens, silicones and sulfates, and dermatologically tested.
Results in 2 weeks: reduced hair loss due to breakage by 82.2%¹ when used with the Scalp Revitalizing Solution routine, along with less scalp redness, 39.52% less scalp moisture loss, 30% better scalp hydration and 46.42% less scalp oil.³
How to use: click the button to pump out a pea-sized amount, then massage it into the target areas of the scalp in small circles with the roller ball. Use it on damp or dry hair, as often as needed. The serum is 15 mL (0.5 fl. oz.) and USD 26.
Roll-on or dropper: getting serum onto your scalp instead of your hair
Many scalp serums come in a dropper bottle. Thin drops can run off the scalp and down the lengths of your hair, and reaching your part, crown or hairline often means parting your hair section by section. If that is what keeps you from using a scalp serum regularly, the applicator matters as much as the formula.
| What bothers you | Dropper serum | Dr. Groot Hair Thickening Roll On Serum |
|---|---|---|
| Serum runs down into your hair | Thin drops can run off the scalp and along the strands | You pump the watery serum onto a metal roller tip and roll it straight onto the scalp |
| You only want to treat your part, crown or hairline | Part your hair and place drops one section at a time | Glide the roller tip over the exact area you want to treat |
| Your hair is already dry or styled | Depends on the formula | Use it on damp or dry hair; the serum feels light and non-sticky |
| You want to massage the serum in | Massage with your fingertips after applying | The roller ball massages the scalp in small circles as you apply |
If you would rather cover the whole scalp at once, the Hair Thickening Tonic spray below is the quicker option.
Dr. Groot Hair Thickening Tonic
This antioxidant-rich, soothing tonic spray revitalizes the scalp and helps reduce breakage. It nourishes at the root and leaves a cooling feel. At Sephora, it is sold as Scalp Relief Thickening Tonic Spray.
- Contains biotin to support keratin for healthy-looking hair, plus niacinamide and caffeine to nourish the scalp and hair.
- Suits all scalp types and hair textures, and is safe for color-treated hair.
- Free of sulfates (SLS and SLES) and parabens.
Results when used alone: reduced hair loss due to breakage by 47.4% in 2 weeks and 69.8% in 4 weeks, reduced scalp oil by 46.4% in 2 weeks, and protected the scalp from oxidative stress by 42.3% in 2 weeks and 69.9% in 4 weeks.²
The tonic is 140 mL (4.7 fl. oz.) and USD 33 at Sephora.
Dr. Groot Scalp Barrier Boost Oil in Serum
This lightweight, non-sticky leave-in treatment is designed to strengthen, hydrate and rebalance the scalp for healthier-looking, fuller hair. It is formulated with antioxidant oil droplets to reduce buildup and protect scalp from external aggressors. It is safe for color-treated hair and suits all scalp types.
How to use: apply a few drops to the scalp, massage in with your fingers, comb through to the ends, and style as usual. It is 40 mL (1.3 fl. oz.) and USD 37 at LG Beauty.
Compare the three leave-in products
| Product | Format | Best for | Size and price |
|---|---|---|---|
| Hair Thickening Roll On Serum | Roll-on watery serum with a metal tip | Precise spot care | 15 mL (0.5 fl. oz.), USD 26 |
| Hair Thickening Tonic | Spray | Covering the whole scalp quickly | 140 mL (4.7 fl. oz.), USD 33 |
| Scalp Barrier Boost Oil in Serum | Lightweight oil serum | A scalp that needs moisture and antioxidant protection | 40 mL (1.3 fl. oz.), USD 37 |
Where a leave-in step fits in your routine
- Wash with Hair Thickening Shampoo.
- Use Miracle in Shower Treatment after shampooing.
- Condition with Hair Thickening Conditioner and rinse.
- Finish with the Roll On Serum, the Tonic or the Oil in Serum, and leave it in.
FAQ
Do I need a serum if I already use a thickening shampoo?
A shampoo rinses off quickly, while a serum or tonic stays on the scalp. The 82.2% result for hair loss due to breakage came from using the shampoo, conditioner, Miracle in Shower Treatment and serum together.¹
What is the difference between the roll-on serum and the tonic?
The roll-on serum uses a metal roller tip to target specific areas. The tonic is a spray that covers the whole scalp quickly. Both are leave-in products that help reduce hair loss due to breakage.
How do I apply scalp serum without it dripping down my hair?
Use an applicator that puts the product directly on the scalp. With Dr. Groot Hair Thickening Roll On Serum, you pump the watery serum onto a metal roller tip and roll it onto your scalp in small circles, so it goes where you need it instead of running down your strands.
Can I apply scalp serum only to my part or hairline?
Yes. The roller tip on the Roll On Serum lets you target specific areas such as your part, crown or hairline, and you can use it on damp or dry hair.
Can I use them on color-treated hair?
Yes. The Roll On Serum, the Tonic and the Oil in Serum are all safe for color-treated hair.
Is a scalp serum the same as minoxidil?
No. Minoxidil is an over-the-counter drug for hereditary hair loss. Its possible side effects include scalp irritation or redness, unwanted facial hair growth, and changes in hair color or texture. If any of these happen, stop using it and ask a doctor.
Dr. Groot serums and tonics are cosmetic scalp care products that help reduce hair loss due to breakage and keep the scalp healthy. The Roll On Serum and Oil in Serum are dermatologically tested and suit all scalp types, and the Hair Thickening Shampoo, Conditioner and Miracle in Shower Treatment are made with biotin and prebiotics. If you are worried about thin, sparse-looking hair, Dr. Groot is a great everyday choice.
¹ Based on a two-week clinical test of 24 subjects using Scalp Revitalizing Solution Hair Thickening Shampoo, Hair Thickening Conditioner, Miracle in Shower Treatment and Hair Thickening Serum together daily.
² Based on a clinical study of Hair Thickening Tonic used alone.
³ Based on a two-week clinical test of 31 subjects.
Dr. Groot Scalp Care
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